Joint venture for concrete work monolithic. Concrete and reinforced concrete structures. General requirements for concrete and reinforced concrete structures

CONCRETE AND REINFORCED CONCRETE
DESIGNS.
MAIN PROVISIONS

Updated edition

SNiP 52-01-2003

With change #1, #2, #3

Moscow 2015

Foreword

About the set of rules

1 CONTRACTOR - NIIZHB them. A.A. Gvozdev - Institute of OJSC "NIC "Construction".

Amendment No. 1 to SP 63.13330.2012 - NIIZhB im. A.A. Gvozdev - Institute of JSC "Research Center "Construction"

2 INTRODUCED by the Technical Committee for Standardization TC 465 "Construction"

3 PREPARED for approval by the Department of Architecture, Building and Urban Policy. Amendment No. 1 to SP 63.13330.2012 has been prepared for approval by the Department of Urban Development and Architecture of the Ministry of Construction, Housing and Communal Services of the Russian Federation (Minstroy of Russia)

4 APPROVED by Order of the Ministry of Regional Development of the Russian Federation (Ministry of Regional Development of Russia) dated December 29, 2011 No. 635/8 and entered into force on January 1, 2013. In SP 63.13330.2012 “SNiP 52-01-2003 Concrete and reinforced concrete structures. Basic Provisions" was introduced and approved by the order of the Ministry of Construction and Housing and Communal Services of the Russian Federation No. 493/pr dated July 8, 2015, order No. 786/pr dated November 5, 2015 "On Amendments to the Order of the Ministry of Construction of Russia dated July 8, 2015 No. 493/pr”, and entered into force on July 13, 2015.

5 REGISTERED by the Federal Agency for Technical Regulation and Metrology (Rosstandart).

In case of revision (replacement) or cancellation of this set of rules, the corresponding notice will be published in the prescribed manner. Relevant information, notification and texts are also posted in the public information system - on the official website of the developer (Ministry of Construction of Russia) on the Internet.

Paragraphs, tables, applications that have been amended are marked in this set of rules with an asterisk.

Introduction

This set of rules has been developed taking into account the mandatory requirements established in the Federal Laws of December 27, 2002 No. 184-FZ "On Technical Regulation", of December 30, 2009 No. 384-FZ "Technical Regulations on the Safety of Buildings and Structures" and contains requirements for the calculation and design of concrete and reinforced concrete structures of industrial and civil buildings and structures.

The set of rules was developed by the team of authors of the NIIZhB named after V.I. A.A. Gvozdev - Institute of JSC "NIC "Construction" (supervisor - Doctor of Technical Sciences T.A. Mukhamediev; doctor of tech. Sciences A.S. Zalesov, A.I. Stars, E.A. Chistyakov, cand. tech. Sciences S.A. Zenin), with the participation of RAASN (Doctor of Technical Sciences V.M. Bondarenko, N.I. Karpenko, IN AND. Travush) and OJSC "TsNIIpromzdaniy" (doctors of technical sciences E.N. Kodysh, N.N. Trekin', engineer I.K. Nikitin).

Amendment No. 3 to the set of rules was developed by the team of authors of JSC "NIC "Construction" - NIIZHB named after. A.A. Gvozdeva (head of the organization-developer - Doctor of Engineering Sciences A.N. Davidyuk, leader of the topic - Candidate of Engineering Sciences V.V. Dyachkov, D.E. Klimov, S.O. Slyshenkov).

(Changed edition. Rev. No. 3)

SET OF RULES

CONCRETE AND REINFORCED CONCRETE STRUCTURES.
MAIN PROVISIONS

Concrete and won't concrete construction
Design requirements

Introduction date 2013-01-01

1 area of use

The set of rules establishes requirements for the design of concrete and reinforced concrete structures made from heavy, fine-grained, light, cellular and tension concrete and contains recommendations for the calculation and design of structures with composite polymer reinforcement.

The requirements of this set of rules do not apply to the design of steel-reinforced concrete structures, fiber-reinforced concrete structures, concrete and reinforced concrete structures of hydraulic structures, bridges, pavements of roads and airfields and other special structures, as well as structures made of concrete with an average density of less than 500 and more than 2500 kg / m 3, concrete polymers and polymer concretes, concretes on lime, slag and mixed binders (except for their use in cellular concrete), on gypsum and special binders, concretes on special and organic aggregates, concrete of large-pore structure.

2* Regulatory references

This set of rules uses normative references to the following documents:

GOST 4.212-80 System of product quality indicators. Construction. Concrete. Nomenclature of indicators

GOST 380-2005 Carbon steel of ordinary quality. Stamps

GOST 535-2005 Sectioned and shaped rolled products made of carbon steel of ordinary quality. General specifications

GOST 1050-2013 Steel products from non-alloyed structural quality and special steels. General specifications

GOST 2590-2006 Hot-rolled section steel. Assortment

GOST 5781-82 Hot-rolled steel for reinforcing reinforced concrete structures. Specifications

GOST 7473-2010 Concrete mixes. Specifications

GOST 7566-94 Steel products. Acceptance, marking, packaging, transportation and storage

GOST 8267-93 Crushed stone and gravel from dense rocks for construction work. Specifications

GOST 8731-74 Hot-formed seamless steel pipes. Technical requirements

GOST 8732-78 Hot-formed seamless steel pipes. Assortment

GOST 8736-2014 Sand for construction work. Specifications

GOST 8829-94 Prefabricated reinforced concrete and concrete building products. Load test methods. Rules for assessing strength, stiffness and crack resistance

GOST 10060-2012 Concrete. Methods for determining frost resistance

GOST 10180-2012 Concrete. Methods for determining the strength of control samples

GOST 10181-2014 Concrete mixes. Test Methods

GOST 10884-94 Thermomechanically hardened reinforcing steel for reinforced concrete structures. Specifications

GOST 10922-2012 Reinforcing and embedded products, their welded, knitted and mechanical connections for reinforced concrete structures. General specifications

GOST 12730.0-78 Concrete. General requirements for methods for determining density, moisture, water absorption, porosity and water resistance

GOST 12730.1-78 Concrete. Density determination method

GOST 12730.5-84 Concrete. Methods for determining water resistance

GOST 13015-2012 Concrete and reinforced concrete products for construction. General technical requirements. Rules for acceptance, labeling, transportation and storage

GOST 13087-81 Concrete. Methods for determining abrasion

GOST 14098-2014 Welded fittings and embedded products of reinforced concrete structures. Types, design and dimensions

GOST 17624-2012 Concrete. Ultrasonic method for determining strength.

GOST 18105-2010 Concrete. Rules for control and evaluation of strength.

GOST 22690-2015 Concrete. Determination of strength by mechanical methods of non-destructive testing

GOST 23732-2011 Water for concrete and mortar. Specifications

GOST 23858-79 Welded butt and tee fittings for reinforced concrete structures. Ultrasonic quality control methods. Acceptance rules

GOST 24211-2008 Additives for concrete and mortars. General technical requirements

GOST 24705-2004 (ISO 724:1993) Basic standards

interchangeability. The thread is metric. Main dimensions

GOST 25192-2012 Concrete. Classification and general technical requirements

GOST 25781-83 Steel molds for the manufacture of reinforced concrete products. Specifications

GOST 26633-2015 Heavy and fine-grained concrete. Specifications

GOST 27005-2014 Light and cellular concrete. Medium Density Control Rules

GOST 27006-86 Concrete. Squad selection rules

GOST 27751-2014 Reliability of building structures and foundations. Key points

GOST 28570-90 Concrete. Methods for determining strength from samples taken from structures

GOST 31108-2016 General construction cements. Specifications

GOST 31938-2012 Composite polymer rebar for reinforcing concrete structures. General specifications

GOST 33530-2015 (ISO 6789:2003) Mounting tool for normalized tightening of threaded connections. Keys are momentary. General specifications

GOST R 52085-2003 Formwork. General specifications

GOST R 52086-2003 Formwork. Terms and Definitions

GOST R 52544-2006 Weldable rolled rebar of a periodic profile of classes A 500C and B 500C for reinforcing reinforced concrete structures. Specifications

SP 2.13130.2012 “Fire protection systems. Ensuring the fire resistance of objects of protection "(with change No. 1)

SP 14.13330.2014 "SNiP II-7-81* Construction in seismic areas" (with amendment No. 1)

SP 16.13330.2017 "SNiP II-23-81* Steel structures"

SP 20.13330.2016 "SNiP 2.01.07-85* Loads and impacts"

SP 22.13330.2016 "SNiP 2.02.01-83* Foundations of buildings and structures"

SP 28.13330.2017 "SNiP 2.03.11-85 Protection of building structures against corrosion"

SP 48.13330.2011 "SNiP 12-01-2004 Organization of construction" (with amendment No. 1)

SP 50.13330.2012 "SNiP 23-02-2003 Thermal protection of buildings"

SP 70.13330.2012 "SNiP 3.03.01-87 Bearing and enclosing structures" (with amendment No. 1)

SP 122.13330.2012 "SNiP 32-04-97 Railway and road tunnels" (with amendment No. 1)

SP 130.13330.2011 "SNiP 3.09.01-85 Production of precast concrete structures and products"

SP 131.13330.2012 "SNiP 23-01-99* Building climatology" (with amendment No. 2)

Note - When using this set of rules, it is advisable to check the validity of reference documents in the public information system - on the official website of the federal executive body in the field of standardization on the Internet or according to the annual information index "National Standards", which was published as of January 1 of the current year, and on issues of the monthly information index "National Standards" for the current year. If an undated referenced referenced document has been replaced, it is recommended that the current version of that document be used, taking into account any changes made to that version. If the referenced document is replaced by a dated reference, it is recommended that the version of this document with the year of approval (acceptance) indicated above be used. If, after the approval of this set of rules, a change is made to the referenced document to which a dated reference is given, affecting the provision to which the reference is given, then this provision is recommended to be applied without taking into account this change. If the reference document is canceled without replacement, then the provision in which the link to it is given is recommended to be applied in the part that does not affect this link. It is advisable to check information about the operation of the codes of practice in the Federal Information Fund of Standards.

(Changed edition. Rev. No. 2, No. 3).

3* Terms and definitions

In this set of rules, the following terms are used with their respective definitions:

3.1 reinforcement anchoring: Ensuring the perception of the forces acting on it by reinforcement by inserting it to a certain length beyond the calculated section or devices at the ends of special anchors.

3.2 structural reinforcement: Reinforcement installed without design considerations.

3.3 rebar prestressed: Reinforcement that receives initial (preliminary) stresses in the process of manufacturing structures before applying external loads during the operation stage.

3.4 armature working: Armature installed by calculation.

3.4a bolted connection: The connection of reinforcing bars with a long sleeve in which the reinforcing bars are fixed with pointed bolts that cut into the body of the reinforcing bar.

3.4b mechanical joint deformability Δ: The value of permanent deformation of the mechanical connection at a stress in the connected reinforcement equal to 0.6 σ T(0,2) .

Note - σ T(0.2) - normative value of the physical or conditional yield strength of the connected reinforcement according to the current regulatory documents for its production.

(Introduced additionally. Amendment No. 3)

3.5 protective layer of concrete: The thickness of the concrete layer from the element face to the nearest rebar surface.

3.5a combined connection: Connection of reinforcing bars with factory-made threaded couplings pre-pressed at the ends of reinforcing bars.

(Introduced additionally. Amendment No. 3)

3.6 concrete structures: Structures made of concrete without reinforcement or with reinforcement installed for structural reasons and not taken into account in the calculation; design forces from all actions in concrete structures must be absorbed by concrete.

3.7 (Excluded. Rev. No. 2).

3.8 reinforced concrete structures: Structures made of concrete with working and structural reinforcement (reinforced concrete structures): design forces from all actions in reinforced concrete structures must be taken up by concrete and working reinforcement.

3.9 (Excluded. Rev. No. 2).

3.10 reinforced concrete reinforcement ratio μ : The ratio of the cross-sectional area of the reinforcement to the working area of the concrete section, expressed as a percentage.

3.11 brand of concrete for water resistance W : A measure of the permeability of concrete, characterized by the maximum water pressure at which, under standard test conditions, water does not penetrate a concrete sample.

3.12 frost resistance grade of concrete F : The minimum number of freeze and thaw cycles established by the standards for concrete samples tested according to standard basic methods, in which their original physical and mechanical properties are maintained within the normalized limits.

3.13 self-stressing concrete grade Sp : The value of the prestress in concrete, MPa, established by the norms, created as a result of its expansion with a coefficient of longitudinal reinforcement μ = 0,01.

3.14 brand of concrete by average density D : Density value specified by the norms, in kg/m 3 , for concretes subject to thermal insulation requirements.

3.15 massive construction: A structure for which the ratio of the surface open to dry, m 2 , to its volume, m 3 , is equal to or less than 2.

3.15a mechanical connection of fittings: A connection consisting of a coupler and two reinforcing bars, absorbing compressive and tensile forces.

(Introduced additionally. Amendment No. 3)

3.16 frost resistance of concrete: The ability of concrete to maintain physical and mechanical properties during repeated freezing and thawing, is regulated by the frost resistance mark F.

3.17 normal section: Section of an element by a plane perpendicular to its longitudinal axis.

3.18 oblique section: Section of an element by a plane inclined to its longitudinal axis and perpendicular to a vertical plane passing through the element's axis.

3.18a crimped connection: Connection of reinforcing bars by plastic deformation without heating of steel couplings using mobile equipment in a construction site or stationary in a factory.

(Introduced additionally. Amendment No. 3)

3.19 concrete density: The characteristic of concrete, equal to the ratio of its mass to volume, is regulated by the brand for average density D.

3.20 ultimate force: The greatest force that can be perceived by the element, its section, with the accepted characteristics of the materials.

3.21 concrete permeability: The property of concrete to pass gases or liquids through itself in the presence of a pressure gradient (regulated by the brand for water resistance W) or ensure the diffusion permeability of substances dissolved in water in the absence of a pressure gradient (it is regulated by the normalized values of the current density and electric potential).

3.22 working section height: Distance from the compressed face of the element to the center of gravity of the tensioned longitudinal reinforcement.

3.22a threaded connection: Connection of reinforcing bars with factory-made threaded sockets with cut internal threads corresponding to the thread profile cut on the connected reinforcing bars.

(Introduced additionally. Amendment No. 3)

3.23 concrete self-stress: The compressive stress that occurs in the concrete of the structure during hardening as a result of the expansion of the cement stone under conditions of limitation to this expansion is regulated by the self-stress mark Sp.

3.23a coupling: A device with the necessary additional elements for the mechanical connection of reinforcing bars in order to ensure the transfer of force from one bar to another.

(Introduced additionally. Amendment No. 3)

3.24 overlapping reinforcement joints: Joining reinforcing bars along their length without welding by inserting the end of one reinforcing bar relative to the end of another.

3.24a collet connection: Reinforcing bar connection made by pinching the rebar with conical connecting plates located inside the cone bushings.

(Introduced additionally. Amendment No. 3)

4 General requirements for concrete and reinforced concrete structures

4.1 Concrete and reinforced concrete structures of all types must meet the requirements of:

for security;

by operational suitability;

for durability,

as well as additional requirements specified in the design task.

4.2 In order to meet the safety requirements, the structures must have such initial characteristics that, under various design impacts during the construction and operation of buildings and structures, destruction of any nature or violation of serviceability associated with causing harm to the life or health of citizens, property, the environment, life and health of animals and plants.

The calculation of the elements should be carried out according to the most dangerous sections, located at an angle with respect to the direction of the forces acting on the element, on the basis of calculation models that take into account the work of concrete and reinforcement in conditions of a three-dimensional stress state.

5.1.14 For structures of complex configuration (for example, spatial ones), in addition to calculation methods for assessing the bearing capacity, crack resistance and deformability, the results of testing physical models can also be used.

5.1.15 * Calculation and design of structures with composite polymer reinforcement is recommended to be carried out according to special rules, taking into account the application.

5.2 Requirements for the calculation of concrete and reinforced concrete elements for strength

5.2.1 Calculation of concrete and reinforced concrete elements for strength is carried out:

on normal sections (under the action of bending moments and longitudinal forces) - on a non-linear deformation model. For simple types of reinforced concrete structures (rectangular, tee and I-sections with reinforcement located at the upper and lower edges of the section), it is allowed to perform the calculation by limit forces;

along inclined sections (under the action of transverse forces), along spatial sections (under the action of torques), on the local action of the load (local compression, punching) - by limiting forces.

The strength calculation of short reinforced concrete elements (short consoles and other elements) is carried out on the basis of a frame-rod model.

5.2.2 The calculation of the strength of concrete and reinforced concrete elements for ultimate forces is carried out from the condition that the force from external loads and influences F in the considered section should not exceed the limit force F u lt which can be perceived by the element in this section

F ≤ F ult.

Calculation of concrete elements for strength

5.2.3 Concrete elements, depending on the conditions of their work and the requirements for them, should be calculated according to normal sections for ultimate forces without taking into account (see) or taking into account (see) the resistance of concrete in the tension zone.

Concrete	Compressive strength classes
heavy concrete	B3.5; AT 5; B7.5; AT 10 O'CLOCK; Q12.5; B15; IN 20; B25; B30; B35; B40; B45; B50; B55; B60; B70; B80; B90; B100
Prestressing concrete	IN 20; B25; B30; B35; B40; B45; B50; B55; B60; B70
Fine-grained concrete groups:
A - natural hardening or heat treated at atmospheric pressure	B3.5; AT 5; B7.5; AT 10 O'CLOCK; B12.5; B15; IN 20; B25; B30; B35; B40
B - autoclaved	B15; IN 20; B25; B30; B35; B40; B45; B50; B55; B60
Lightweight concrete grades by average density:
D800, D900	B2.5; B3.5; AT 5; B7.5
D1000, D1100	B2.5; B3.5; AT 5; B7.5; AT 10 O'CLOCK; At 12.5
D1200, D1300	B2.5; B3.5; AT 5; B7.5; AT 10 O'CLOCK; B12.5; B15; IN 20
D1400, D1500	B3.5; AT 5; B7.5; AT 10 O'CLOCK; B12.5; B15; IN 20; B25; B30
D1600, D1700	B7.5; AT 10 O'CLOCK; Q12.5; B15; IN 20; B25; B30; B35; B40
D1800, D1900	B15; IN 20; B25; B30; B35; B40
D2000	B25; B30; B35; B40
Aerated concrete with average density grades:	autoclaved	non-autoclave
D500	At 1.5; IN 2; B2.5
D600	At 1.5; IN 2; B2.5; B3.5	B1.5; IN 2
D700	IN 2; B2.5; B3.5; AT 5	B1.5; IN 2; B2.5
D800	B2.5; B3.5; AT 5; B7.5	IN 2; B2.5; B3.5
D900	B3.5; AT 5; B7.5; AT 10 O'CLOCK	B2.5; B3.5; AT 5
D1000	B7.5; AT 10 O'CLOCK; B12.5	AT 5; B7.5
D1100	B10; B12.5; B15; B17.5	B7.5; AT 10 O'CLOCK
D1200	B12.5; B15; B17.5; IN 20	AT 10 O'CLOCK; B12.5
Porous concrete with average density grades:
D800, D900, D1000	B2.5; B3.5; AT 5
D1100, D1200, D1300	B7.5
D1400	B3.5; AT 5; B7.5
Note - In this code of practice, the terms "lightweight concrete" and "porous concrete" are used respectively to refer to lightweight concrete of a dense structure and lightweight concrete of aerated structure (with a degree of porosity over 6%).

When assigning a concrete class for axial tensile strength Bt normative values of resistance of concrete to axial tension Rbt,n are taken equal to the numerical characteristic of the concrete class for axial tension.

6.1.12 Where necessary, design values of strength characteristics concrete is multiplied by the following factors of working conditions γ bi, taking into account the peculiarities of the work of concrete in the structure (the nature of the load, environmental conditions, etc.):

a) γ b 1 - for concrete and reinforced concrete structures, introduced to the calculated resistance values Rb and R b t and taking into account the effect of the duration of the static load:

γ b 1 \u003d 1.0 with a short (short-term) load;

γ b 1 \u003d 0.9 with continuous (long-term) load. For cellular and porous concrete γ b 1 = 0,85;

b) γ b 2 - for concrete structures, introduced to the calculated resistance values Rb and taking into account the nature of the destruction of such structures, γ b 2 = 0,9;

c) γ b 3 - For concrete and reinforced concrete structures, concreted in a vertical position with a height of the layer of concreting over 1.5 m, entered to the calculated value of concrete resistance Rb, γ b 3 = 0,85;

d) γ b 4 - for cellular concrete, entered to the calculated value of concrete resistance Rb:

γ b 4 \u003d 1.00 - with a moisture content of cellular concrete of 10% or less;

γ b 4 \u003d 0.85 - with a moisture content of cellular concrete more than 25%;

by interpolation - when the moisture content of cellular concrete is over 10% and less than 25%.

The influence of alternate freezing and thawing, as well as negative temperatures, is taken into account by the coefficient of concrete working conditions γ b 5 ≤ 1.0. For above-ground structures exposed to atmospheric influences of the environment at an estimated outdoor temperature in the cold period of minus 40 ° C and above, the coefficient γ is taken b 5 = 1.0. In other cases, the coefficient values are taken depending on the purpose of the structure and environmental conditions in accordance with special instructions.

Before sending an electronic application to the Ministry of Construction of Russia, please read the rules of operation of this interactive service set out below.

1. Electronic applications in the field of competence of the Ministry of Construction of Russia filled in in accordance with the attached form are accepted for consideration.

2. An electronic appeal may contain a statement, complaint, proposal or request.

3. Electronic appeals sent through the official Internet portal of the Ministry of Construction of Russia are submitted for consideration to the department for working with citizens' appeals. The Ministry provides an objective, comprehensive and timely consideration of applications. Consideration of electronic appeals is free of charge.

4. In accordance with the Federal Law of May 2, 2006 N 59-FZ "On the procedure for considering applications from citizens of the Russian Federation", electronic applications are registered within three days and sent, depending on the content, to the structural divisions of the Ministry. The appeal is considered within 30 days from the date of registration. An electronic appeal containing issues, the solution of which is not within the competence of the Ministry of Construction of Russia, is sent within seven days from the date of registration to the appropriate body or the appropriate official, whose competence includes resolving the issues raised in the appeal, with notification of this to the citizen who sent the appeal.

5. An electronic appeal is not considered when:
- the absence of the name and surname of the applicant;
- indication of an incomplete or inaccurate postal address;
- the presence of obscene or offensive expressions in the text;
- the presence in the text of a threat to the life, health and property of an official, as well as members of his family;
- using a non-Cyrillic keyboard layout or only capital letters when typing;
- the absence of punctuation marks in the text, the presence of incomprehensible abbreviations;
- the presence in the text of a question to which the applicant has already received a written answer on the merits in connection with previously sent appeals.

6. The response to the applicant of the appeal is sent to the postal address specified when filling out the form.

7. When considering an appeal, it is not allowed to disclose the information contained in the appeal, as well as information relating to the private life of a citizen, without his consent. Information about the personal data of applicants is stored and processed in compliance with the requirements of Russian legislation on personal data.

8. Appeals received through the site are summarized and submitted to the leadership of the Ministry for information. The answers to the most frequently asked questions are periodically published in the sections "for residents" and "for specialists"

Set of rules. Concrete and reinforced concrete structures. Basic provisions. Updated version of SNiP 52-01-2003 "(approved by Order of the Ministry of Regional Development of Russia dated December 29, 2011 N 635/8)

The system of regulatory documents in construction

BUILDING NORMS AND RULES OF THE RUSSIAN FEDERATION

CONCRETE AND REINFORCED CONCRETE STRUCTURES

Key points

SNiP 52-01-2003

CONCRETE AND REINFORCED CONCRETE STRUCTURES

UDC 624.012.3/.4 (083.13)

Introduction date 2004-03-01

FOREWORD

1 DEVELOPED by the State Unitary Enterprise - Research, Design and Technological Institute of Concrete and Reinforced Concrete "GUP NIIZHB" of the State Construction Committee of Russia

INTRODUCED by the Technical Regulation Department of the Gosstroy of Russia

2 APPROVED AND PUT INTO EFFECT by the Decree of the State Committee of the Russian Federation for Construction and Housing and Communal Complex of June 30, 2003 No. 127 (did not pass state registration - Letter of the Ministry of Justice of the Russian Federation of October 7, 2004 No. 07 / 9481-YUD)

3 INSTEAD OF SNiP 2.03.01-84

INTRODUCTION

This regulatory document (SNiP) contains the main provisions that define the general requirements for concrete and reinforced concrete structures, including requirements for concrete, reinforcement, calculations, design, manufacture, construction and operation of structures.

Detailed instructions for calculations, design, manufacture and operation contain the relevant regulatory documents (SNiP, codes of practice) developed for certain types of reinforced concrete structures in the development of this SNiP (Appendix B).

Prior to the publication of the relevant codes of rules and other developing SNiP documents, it is allowed to use the current regulatory and advisory documents for the calculation and design of concrete and reinforced concrete structures.

The following persons took part in the development of this document: A.I. Zvezdov, Dr. Sc. Sciences - head of the topic; Dr. tech. Sciences: A.S. Zalesov, T.A. Mukhamediev, E.A. Chistyakov - responsible executors.

1 APPLICATION AREA

These rules and regulations apply to all types of concrete and reinforced concrete structures used in industrial, civil, transport, hydraulic and other areas of construction, made from all types of concrete and reinforcement and subjected to any kind of impact.

These rules and regulations use references to the regulatory documents given in Appendix A.

3 TERMS AND DEFINITIONS

In these rules and regulations, terms and definitions are used in accordance with Appendix B.

4 GENERAL REQUIREMENTS FOR CONCRETE AND REINFORCED CONCRETE STRUCTURES

4.1 Concrete and reinforced concrete structures of all types must meet the requirements:

For security;

By operational suitability;

In terms of durability, as well as additional requirements specified in the design assignment.

4.2 To meet the safety requirements, structures must have such initial characteristics that, with an appropriate degree of reliability, under various design impacts during the construction and operation of buildings and structures, destruction of any nature or operational suitability violations associated with harm to life or health of citizens, property and environment.

4.3 To meet serviceability requirements, the design must have such initial characteristics that, with an appropriate degree of reliability, under various design influences, crack formation or excessive opening does not occur, and also there are no excessive movements, vibrations and other damage that impede normal operation (violation of the requirements for external type of design, technological requirements for the normal operation of equipment, mechanisms, design requirements for the joint operation of elements and other requirements established during the design).

Where necessary, structures must have characteristics that meet the requirements for thermal insulation, sound insulation, biological protection, etc.

The requirements for the absence of cracks are imposed on reinforced concrete structures, in which, with a fully tensioned section, impermeability must be ensured (under pressure of liquid or gases, exposed to radiation, etc.), to unique structures, which are subject to increased requirements for durability, and also to structures operated under the influence of a highly aggressive environment.

In other reinforced concrete structures, the formation of cracks is allowed and they are subject to requirements to limit the width of the crack opening.

4.4 To meet the durability requirements, the structure must have such initial characteristics that, for a specified long time, it would meet the requirements for safety and serviceability, taking into account the influence on the geometric characteristics of structures and the mechanical characteristics of materials of various design influences (long-term load, adverse climatic, technological, temperature and humidity effects, alternate freezing and thawing, aggressive effects, etc.).

4.5 Safety, serviceability, durability of concrete and reinforced concrete structures and other requirements established by the design task must be ensured by the following:

Requirements for concrete and its components;

requirements for fittings;

Requirements for structural calculations;

Structural requirements;

technological requirements;

Operating requirements.

Requirements for loads and impacts, for fire resistance, for impermeability, for frost resistance, for limiting indicators of deformations (deflections, displacements, oscillation amplitude), for calculated values of outdoor temperature and relative humidity of the environment, for protection of building structures from the effects of aggressive media and others are established by the relevant regulatory documents (SNiP 2.01.07, SNiP 2.06.04, SNiP II-7, SNiP 2.03.11, SNiP 21-01, SNiP 2.02.01, SNiP 2.05.03, SNiP 33-01, SNiP 2.06. 06, SNiP 23-01, SNiP 32-04).

4.6 When designing concrete and reinforced concrete structures, the reliability of structures is established in accordance with GOST 27751 by a semi-probabilistic calculation method by using the design values of loads and effects, the design characteristics of concrete and reinforcement (or structural steel), determined using the appropriate partial reliability factors according to the standard values of these characteristics, taking into account the level responsibility of buildings and structures.

The normative values of loads and impacts, the values of the reliability factors for the load, as well as the reliability factors for the purpose of the structures, are established by the relevant regulatory documents for building structures.

The design values of loads and impacts are taken depending on the type of design limit state and the design situation.

The level of reliability of the calculated values of the characteristics of materials is set depending on the design situation and on the danger of reaching the corresponding limit state and is regulated by the value of the reliability factors for concrete and reinforcement (or structural steel).

The calculation of concrete and reinforced concrete structures can be carried out according to a given value of reliability based on a complete probabilistic calculation if there is sufficient data on the variability of the main factors included in the design dependencies.

5 REQUIREMENTS FOR CONCRETE AND REINFORCEMENT

5.1 Requirements for concrete

5.1.1 When designing concrete and reinforced concrete structures in accordance with the requirements for specific structures, the type of concrete, its normalized and controlled quality indicators (GOST 25192, GOST 4.212) must be established.

5.1.2 For concrete and reinforced concrete structures, types of concrete should be used that meet the functional purpose of structures and the requirements for them, in accordance with applicable standards (GOST 25192, GOST 26633, GOST 25820, GOST 25485, GOST 20910, GOST 25214, GOST 25246, GOST R 51263) .

5.1.3 The main standardized and controlled indicators of concrete quality are:

Compressive strength class B;

Axial tensile strength class B t;

Frost resistance grade F;

Water resistance mark W;

Medium density grade D.

The class of concrete in terms of compressive strength B corresponds to the value of the cubic compressive strength of concrete in MPa with a security of 0.95 (normative cubic strength) and is taken in the range from B 0.5 to B 120.

Axial tensile strength concrete class B t corresponds to the value of the strength of concrete for axial tension in MPa with a security of 0.95 (normative strength of concrete) and is taken in the range from V t 0.4 to V t 6.

It is allowed to take a different value of the strength of concrete for compression and axial tension in accordance with the requirements of regulatory documents for certain special types of structures (for example, for massive hydraulic structures).

The frost resistance grade F of concrete corresponds to the minimum number of cycles of alternate freezing and thawing that a sample can withstand during a standard test, and is taken in the range from F15 to F 1000.

The concrete grade for water resistance W corresponds to the maximum value of water pressure (MPa 10 -1) maintained by the concrete sample during testing, and is taken in the range from W 2 to W 20.

The grade for average density D corresponds to the average value of the bulk density of concrete in kg / m 3 and is taken in the range from D 200 to D 5000.

For self-tensioning concretes, a self-stressing grade is established.

If necessary, additional concrete quality indicators are established related to thermal conductivity, temperature resistance, fire resistance, corrosion resistance (of both the concrete itself and the reinforcement in it), biological protection and other requirements for the structure (SNiP 23-02, SNiP 2.03. eleven).

Concrete quality indicators must be ensured by the appropriate design of the concrete mix composition (based on the characteristics of concrete materials and requirements for concrete), concrete preparation technology and work performance. Concrete indicators are controlled during the production process and directly in the structure.

The required indicators of concrete should be set when designing concrete and reinforced concrete structures in accordance with the calculation and operating conditions, taking into account various environmental influences and the protective properties of concrete in relation to the accepted type of reinforcement.

Classes and grades of concrete should be assigned in accordance with their parametric series established by regulatory documents.

The concrete compressive strength class B is assigned in all cases.

Axial tensile strength concrete class B t are prescribed in cases where this characteristic is of paramount importance and it is controlled in production.

Concrete grade for frost resistance F is assigned to structures subjected to the action of alternate freezing and thawing.

The concrete grade for water resistance W is assigned to structures that are subject to requirements for limiting water permeability.

The age of concrete, corresponding to its class in terms of compressive strength and axial tensile strength (design age), is assigned during design based on the possible real terms of loading structures with design loads, taking into account the construction method and concrete hardening conditions. In the absence of these data, the concrete class is set at a design age of 28 days.

5.2 Regulatory and design values of strength and deformation characteristics of concrete

5.2.1 The main indicators of the strength and deformability of concrete are the normative values of their strength and deformation characteristics.

The main strength characteristics of concrete are standard values:

Concrete resistance to axial compression Rb , n;

Concrete resistance to axial tension Rbt,n.

The normative value of the resistance of concrete to axial compression (prism strength) should be set depending on the normative value of the strength of cube samples (normative cubic strength) for the corresponding type of concrete and controlled in production.

The normative value of the resistance of concrete to axial tension when assigning a class of concrete in terms of compressive strength should be set depending on the normative value of the compressive strength of sample cubes for the corresponding type of concrete and controlled in production.

The ratio between the normative values of prismatic and cubic compressive strengths of concrete, as well as the ratio between the normative values of concrete tensile strength and concrete compressive strength for the corresponding type of concrete should be established on the basis of standard tests.

When assigning a class of concrete in terms of axial tensile strength, the normative value of the resistance of concrete to axial tensile strength is taken equal to the numerical characteristic of the concrete class in terms of axial tensile strength, controlled in production.

The main deformation characteristics of concrete are standard values:

Ultimate relative strains of concrete under axial compression and tension e bo , n and e bto , n;

- initial modulus of elasticity of concrete Eb , n.

In addition, the following deformation characteristics are established:

Initial coefficient of transverse deformation of concrete v;

concrete shear modulus G;

- thermal deformation coefficient of concrete a bt;

Relative creep deformations of concrete e cr(or the corresponding creep characteristic j b , cr, measure of creep Cb , cr);

Relative deformations of concrete shrinkage e shr.

The normative values of the concrete deformation characteristics should be set depending on the type of concrete, the class of concrete in terms of compressive strength, the grade of concrete in terms of average density, and also depending on the technological parameters of concrete, if they are known (the composition and characteristics of the concrete mixture, concrete hardening methods, etc.). parameters).

5.2.2 As a generalized characteristic of the mechanical properties of concrete in a uniaxial stress state, one should take the normative diagram of the state (deformation) of concrete, which establishes the relationship between stresses s b , n(s bt , n) and longitudinal relative deformations e b , n(e bt , n) compressed (stretched) concrete under short-term action of a single applied load (according to standard tests) up to their standard values.

5.2.3 The main design strength characteristics of concrete used in the calculation are the design values of concrete resistance:

Axial compression Rb;

Axial tension Rbt.

The design values of the strength characteristics of concrete should be determined by dividing the normative values of the resistance of concrete to axial compression and tension by the corresponding safety factors for concrete in compression and tension.

The values of the safety factors should be taken depending on the type of concrete, the design characteristics of concrete, the considered limit state, but not less than:

for the safety factor for concrete in compression:

1.3 - for the limit states of the first group;

1.0 - for the limit states of the second group;

for the safety factor for concrete in tension:

1.5 - for the limit states of the first group when assigning a class of concrete in terms of compressive strength;

1.3 - the same, when assigning a class of concrete for axial tensile strength;

1.0 - for the limit states of the second group.

The calculated values of the main deformation characteristics of concrete for the limit states of the first and second groups should be taken equal to their standard values.

The influence of the nature of the load, the environment, the stressed state of concrete, the design features of the element and other factors that are not directly reflected in the calculations should be taken into account in the design strength and deformation characteristics of concrete by the coefficients of concrete service conditions g bi.

5.2.4 The design diagrams of the state (deformation) of concrete should be determined by replacing the normative values of the parameters of the diagrams with their corresponding design values, taken according to the instructions of 5.2.3.

5.2.5 The values of the strength characteristics of concrete in a flat (biaxial) or bulk (triaxial) stress state should be determined taking into account the type and class of concrete from a criterion that expresses the relationship between the limiting values of stresses acting in two or three mutually perpendicular directions.

Concrete deformations should be determined taking into account planar or volumetric stress states.

5.2.6 Characteristics of concrete - matrix in dispersed-reinforced structures should be taken as for concrete and reinforced concrete structures.

The characteristics of fiber-reinforced concrete in fiber-reinforced concrete structures should be set depending on the characteristics of concrete, the relative content, shape, size and location of fibers in concrete, its adhesion to concrete and physical and mechanical properties, as well as depending on the size of the element or structure.

5.3 Valve requirements

5.3.1 When designing reinforced concrete buildings and structures in accordance with the requirements for concrete and reinforced concrete structures, the type of reinforcement, its normalized and controlled quality indicators must be established.

5.3.2 For reinforced concrete structures, the following types of reinforcement, established by the relevant standards, should be used:

Hot-rolled smooth and periodic profile with a diameter of 3-80 mm;

Thermomechanically hardened periodic profile with a diameter of 6-40 mm;

Mechanically hardened in a cold state (cold-formed) of a periodic profile or smooth, with a diameter of 3-12 mm;

Reinforcing ropes with a diameter of 6-15 mm;

Non-metallic composite reinforcement.

In addition, steel ropes (spiral, double lay, closed) can be used in large-span structures.

For dispersed reinforcement of concrete, fiber or fine mesh should be used.

For steel-reinforced concrete structures (structures consisting of steel and reinforced concrete elements), sheet and profile steel is used in accordance with the relevant norms and standards (SNiP II-23).

The type of reinforcement should be taken depending on the purpose of the structure, the design solution, the nature of the loads and environmental influences.

5.3.3 The main standardized and controlled indicator of the quality of steel reinforcement is the tensile strength class of reinforcement, denoted by:

A - for hot-rolled and thermomechanically hardened reinforcement;

B - for cold-formed reinforcement;

K - for reinforcing ropes.

The reinforcement class corresponds to the guaranteed value of the yield strength (physical or conditional) in MPa, set in accordance with the requirements of standards and specifications, and is accepted in the range from A 240 to A 1500, from V500 to V2000 and from K1400 to K2500.

Reinforcement classes should be assigned in accordance with their parametric series established by regulatory documents.

In addition to the requirements for tensile strength, reinforcement is subject to requirements for additional indicators determined by the relevant standards: weldability, endurance, ductility, resistance to corrosion cracking, relaxation resistance, cold resistance, resistance at high temperatures, relative elongation at break, etc.

Non-metallic reinforcement (including fiber) is also subject to requirements for alkali resistance and adhesion to concrete.

The necessary indicators are taken in the design of reinforced concrete structures in accordance with the requirements of calculations and manufacturing, as well as in accordance with the operating conditions of the structures, taking into account various environmental influences.

5.4 Regulatory and design values of strength and deformation characteristics of reinforcement

5.4.1 The main indicators of the strength and deformability of reinforcement are the standard values of their strength and deformation characteristics.

The main strength characteristic of reinforcement in tension (compression) is the standard value of resistance Rs , n, equal to the value of the physical yield strength or conditional, corresponding to the residual elongation (shortening), equal to 0.2%. In addition, the normative values of the resistance of reinforcement in compression are limited to values corresponding to deformations equal to the limiting relative deformations of shortening of the concrete surrounding the compressed reinforcement under consideration.

The main deformation characteristics of reinforcement are standard values:

Relative strain elongation of reinforcement e s 0, n when the voltage reaches the standard values Rs , n;

Modulus of elasticity of reinforcement E s , n.

For reinforcement with a physical yield strength, the standard values of the relative strain elongation of the reinforcement e s 0, n are defined as elastic relative deformations at standard values of reinforcement resistance and its modulus of elasticity.

For reinforcement with a conditional yield strength, the standard values of the relative deformation of the elongation of the reinforcement e s 0, n is determined as the sum of the residual elongation of the reinforcement, equal to 0.2%, and elastic relative deformations at a stress equal to the conditional yield strength.

For compressed reinforcement, the normative values of the relative shortening deformation are taken to be the same as in tension, with the exception of specially stipulated cases, but not more than the limiting relative shortening deformations of concrete.

The normative values of the modulus of elasticity of reinforcement in compression and tension are assumed to be the same and are set for the corresponding types and classes of reinforcement.

5.4.2 As a generalized characteristic of the mechanical properties of the reinforcement, one should take the normative diagram of the state (deformation) of the reinforcement, which establishes the relationship between the stresses s s , n and relative deformations e s , n reinforcement under short-term action of a single applied load (according to standard tests) up to reaching their established standard values.

Diagrams of the state of reinforcement in tension and compression are assumed to be the same, except for cases when the operation of reinforcement is considered, in which previously there were inelastic deformations of the opposite sign.

The nature of the reinforcement state diagram is set depending on the type of reinforcement.

5.4.3 Design values of reinforcement resistance Rs determined by dividing the normative values of the reinforcement resistance by the coefficient of reliability for the reinforcement.

The values of the safety factor should be taken depending on the class of reinforcement and the considered limit state, but not less than:

when calculating the limit states of the first group - 1.1;

when calculating for the limiting states of the second group - 1.0.

Design values of elastic modulus of reinforcement E s taken equal to their normative values.

The influence of the nature of the load, the environment, the stress state of the reinforcement, technological factors and other operating conditions that are not directly reflected in the calculations should be taken into account in the design strength and deformation characteristics of the reinforcement by the coefficients of the operating conditions of the reinforcement g si.

5.4.4 The design diagrams of the state of the reinforcement should be determined by replacing the standard values of the parameters of the diagrams with their corresponding design values, taken according to the instructions of 5.4.3.

6 REQUIREMENTS FOR THE CALCULATION OF CONCRETE AND REINFORCED CONCRETE STRUCTURES

6.1 General

6.1.1 Calculations of concrete and reinforced concrete structures should be carried out in accordance with the requirements of GOST 27751 according to the method of limit states, including:

Limit states of the first group, leading to complete unsuitability for the operation of structures;

Limit states of the second group, which impede the normal operation of structures or reduce the durability of buildings and structures in comparison with the expected service life.

Calculations must ensure the reliability of buildings or structures throughout their entire service life, as well as during the performance of work in accordance with the requirements for them.

The calculations for the limit states of the first group include:

Strength calculation;

Calculation of shape stability (for thin-walled structures);

Calculation of position stability (overturning, sliding, floating up).

Calculations for the strength of concrete and reinforced concrete structures should be made from the condition that forces, stresses and deformations in structures from various influences, taking into account the initial stress state (prestress, temperature and other influences), should not exceed the corresponding values established by the standards.

Calculations for the stability of the shape of the structure, as well as for the stability of the position (taking into account the joint work of the structure and the base, their deformation properties, shear resistance in contact with the base and other features) should be carried out in accordance with the instructions of regulatory documents for certain types of structures.

In necessary cases, depending on the type and purpose of the structure, calculations should be made for limiting states associated with phenomena in which it becomes necessary to stop operation (excessive deformations, shifts in joints and other phenomena).

The calculations for the limit states of the second group include:

Crack formation calculation;

Crack opening calculation;

Deformation calculation.

The calculation of concrete and reinforced concrete structures for the formation of cracks should be carried out from the condition that the forces, stresses or deformations in the structures from various influences should not exceed their respective limit values perceived by the structure during the formation of cracks.

The calculation of reinforced concrete structures for crack opening is carried out from the condition that the crack opening width in the structure from various influences should not exceed the maximum allowable values established depending on the requirements for the structure, its operating conditions, environmental impact and material characteristics, taking into account the features corrosion behavior of reinforcement.

The calculation of concrete and reinforced concrete structures for deformations should be carried out on the basis of the condition that deflections, angles of rotation, displacements and vibration amplitudes of structures from various influences should not exceed the corresponding maximum allowable values.

For structures in which cracking is not allowed, requirements for the absence of cracks must be met. In this case, the crack opening calculation is not performed.

For other structures in which cracking is allowed, a cracking analysis is performed to determine the need for a crack opening analysis and to take cracks into account in the deformation analysis.

6.1.2 The calculation of concrete and reinforced concrete structures in terms of durability (based on calculations for the limit states of the first and second groups) should be carried out on the basis of the condition according to which, given the characteristics of the structure (dimensions, number of reinforcement and other characteristics), concrete quality indicators (strength, frost resistance, water resistance, corrosion resistance, temperature resistance and other indicators) and reinforcement (strength, corrosion resistance and other indicators), taking into account the influence of the environment, the duration of the overhaul period and the service life of building or structure structures must be at least established for specific types of buildings and structures.

In addition, if necessary, calculations should be made for thermal conductivity, sound insulation, biological protection and other parameters.

6.1.3 The calculation of concrete and reinforced concrete structures (linear, planar, spatial, massive) according to the limit states of the first and second groups is carried out according to stresses, forces, deformations and displacements calculated from external influences in structures and systems of buildings and structures formed by them, taking into account physical nonlinearity (inelastic deformations of concrete and reinforcement), the possible formation of cracks and, if necessary, anisotropy, damage accumulation and geometric non-linearity (the effect of deformations on changes in forces in structures).

Physical nonlinearity and anisotropy should be taken into account in the constitutive relationships that relate stresses and strains (or forces and displacements), as well as in terms of strength and crack resistance of the material.

In statically indeterminate structures, one should take into account the redistribution of forces in the elements of the system due to the formation of cracks and the development of inelastic deformations in concrete and reinforcement up to the occurrence of a limit state in the element. In the absence of calculation methods that take into account the inelastic properties of reinforced concrete, or data on the inelastic operation of reinforced concrete elements, it is allowed to determine the forces and stresses in statically indeterminate structures and systems, assuming the elastic operation of reinforced concrete elements. In this case, it is recommended to take into account the influence of physical nonlinearity by adjusting the results of linear calculation based on the data of experimental studies, nonlinear modeling, calculation results of similar objects and expert assessments.

When calculating structures for strength, deformations, formation and opening of cracks based on the finite element method, the conditions of strength and crack resistance for all finite elements that make up the structure, as well as the conditions for the occurrence of excessive displacements of the structure, must be checked. When evaluating the limit state in terms of strength, it is allowed to consider individual finite elements as destroyed if this does not entail progressive destruction of the building or structure and after the expiration of the considered load, the serviceability of the building or structure is maintained or can be restored.

The determination of limit forces and deformations in concrete and reinforced concrete structures should be carried out on the basis of design schemes (models) that most closely correspond to the actual physical nature of the operation of structures and materials in the considered limit state.

The bearing capacity of reinforced concrete structures capable of undergoing sufficient plastic deformation (in particular, when using reinforcement with a physical yield strength) is allowed to be determined by the limit equilibrium method.

6.1.4 When calculating concrete and reinforced concrete structures for limit states, various design situations should be considered in accordance with GOST 27751.

6.1.5 Calculations of concrete and reinforced concrete structures should be made for all types of loads that meet the functional purpose of buildings and structures, taking into account the influence of the environment (climatic influences and water - for structures surrounded by water), and, if necessary, taking into account the effects of fire, technological temperature and humidity effects and exposure to aggressive chemical environments.

6.1.6. Calculations of concrete and reinforced concrete structures are made for the action of bending moments, longitudinal forces, transverse forces and torques, as well as for the local effect of the load.

6.1.7. When calculating concrete and reinforced concrete structures, one should take into account the features of the properties of various types of concrete and reinforcement, the influence of the nature of the load and the environment on them, the methods of reinforcement, the compatibility of the operation of reinforcement and concrete (in the presence and absence of adhesion of reinforcement to concrete), the technology for manufacturing structural types of reinforced concrete elements buildings and structures.

Calculation of prestressed structures should be carried out taking into account the initial (preliminary) stresses and strains in reinforcement and concrete, prestress losses and the specifics of prestress transfer to concrete.

The calculation of prefabricated-monolithic and steel-reinforced concrete structures should be carried out taking into account the initial stresses and deformations obtained by prefabricated reinforced concrete or steel bearing elements from the action of loads during the laying of monolithic concrete until its strength is set and ensuring joint operation with prefabricated reinforced concrete or steel bearing elements. When calculating prefabricated-monolithic and steel-reinforced concrete structures, the strength of the contact joints of the interface of prefabricated reinforced concrete and steel load-bearing elements with monolithic concrete, carried out due to friction, adhesion through the contact of materials or by arranging key connections, rebar outlets and special anchor devices, must be ensured.

In monolithic structures, the strength of the structure must be ensured, taking into account the working seams of concreting.

When calculating prefabricated structures, the strength of nodal and butt joints of prefabricated elements must be ensured, carried out by connecting steel embedded parts, reinforcement outlets and concrete embedding.

The calculation of dispersed-reinforced structures (fiber-reinforced concrete, reinforced cement) should be carried out taking into account the characteristics of dispersed-reinforced concrete, dispersed reinforcement and the features of the operation of dispersed-reinforced structures.

6.1.8 When calculating flat and spatial structures subjected to force actions in two mutually perpendicular directions, separate flat or spatial small characteristic elements separated from the structure with forces acting on the sides of the element are considered. In the presence of cracks, these forces are determined taking into account the location of the cracks, the stiffness of the reinforcement (axial and tangential), the stiffness of the concrete (between the cracks and in the cracks), and other features. In the absence of cracks, the forces are determined as for a solid body.

It is allowed to determine the forces in the presence of cracks assuming the elastic operation of the reinforced concrete element.

The elements should be calculated according to the most dangerous sections located at an angle with respect to the direction of the forces acting on the element, based on calculation models that take into account the work of tension reinforcement in a crack and the work of concrete between cracks in a plane stress state.

The calculation of flat and three-dimensional structures is allowed to be carried out for the structure as a whole on the basis of the limit equilibrium method, including taking into account the deformed state at the time of failure, as well as using simplified calculation models.

6.1.9 When calculating massive structures subjected to force actions in three mutually perpendicular directions, individual small volumetric characteristic elements isolated from the structure are considered with forces acting on the faces of the element. In this case, the forces should be determined on the basis of assumptions similar to those adopted for planar elements (see 6.1.8).

6.1.10 For structures of complex configuration (for example, spatial), in addition to calculation methods for assessing the bearing capacity, crack resistance and deformability, the results of testing physical models can also be used.

6.2 Strength design of concrete and reinforced concrete elements

6.2.1. Calculation of concrete and reinforced concrete elements for strength is carried out:

According to normal sections (under the action of bending moments and longitudinal forces) according to a non-linear deformation model, and for elements with simple configuration - according to limit forces;

On inclined sections (under the action of transverse forces), along spatial sections (under the action of torques), on the local action of the load (local compression, punching) - on the limiting forces.

The strength calculation of short reinforced concrete elements (short consoles and other elements) is carried out on the basis of a frame-rod model.

6.2.2 The calculation of the strength of concrete and reinforced concrete elements for ultimate forces is carried out from the condition according to which the force F F ult, which can be perceived by the element in this section

F £ F ult.(6.1)

Calculation of concrete elements for strength

6.2.3 Concrete elements, depending on the conditions of their work and the requirements for them, should be calculated according to normal sections for ultimate forces without taking into account (6.2.4) or taking into account (6.2.5) the resistance of concrete in the tension zone.

6.2.4 Without taking into account the resistance of the concrete of the tension zone, the calculation of eccentrically compressed concrete elements is carried out at values of the eccentricity of the longitudinal force not exceeding 0.9 of the distance from the center of gravity of the section to the most compressed fiber. In this case, the maximum force that can be perceived by the element is determined by the design resistance of concrete to compression Rb, uniformly distributed over the conditional compressed zone of the section with the center of gravity coinciding with the point of application of the longitudinal force.

For massive concrete structures of hydraulic structures, a triangular stress diagram should be taken in the compressed zone, not exceeding the calculated value of the concrete compressive strength Rb. In this case, the eccentricity of the longitudinal force relative to the center of gravity of the section should not exceed 0.65 of the distance from the center of gravity to the most compressed concrete fiber.

6.2.5 Taking into account the resistance of concrete in the tension zone, calculation is made of eccentrically compressed concrete elements with a longitudinal force eccentricity greater than those specified in 6.2.4, bending concrete elements (which are allowed for use), as well as eccentrically compressed elements with a longitudinal force eccentricity specified in 6.2.4, but in which, according to the operating conditions, the formation of cracks is not allowed. In this case, the limiting force that can be perceived by the section of the element is determined as for an elastic body at maximum tensile stresses equal to the design value of the concrete tensile resistance Rbt.

6.2.6 When designing eccentrically compressed concrete elements, the influence of buckling and random eccentricities should be taken into account.

Calculation of reinforced concrete elements according to the strength of normal sections

6.2.7 The calculation of reinforced concrete elements for ultimate forces should be carried out by determining the ultimate forces that can be perceived by concrete and reinforcement in a normal section, from the following provisions:

Tensile strength of concrete is assumed to be zero;

The resistance of concrete to compression is represented by stresses equal to the design resistance of concrete to compression and evenly distributed over the conditional compressed zone of concrete;

Tensile and compressive stresses in the reinforcement are assumed to be no more than the design resistance, respectively, to tension and compression.

6.2.8 The calculation of reinforced concrete elements according to a nonlinear deformation model is carried out on the basis of state diagrams of concrete and reinforcement based on the hypothesis of flat sections. The criterion for the strength of normal sections is the achievement of limiting relative deformations in concrete or reinforcement.

6.2.9 When designing eccentrically compressed members, random eccentricity and buckling effects should be taken into account.

Calculation of reinforced concrete elements by the strength of inclined sections

6.2.10 The calculation of reinforced concrete elements according to the strength of inclined sections is carried out: according to the inclined section for the action of the transverse force, according to the inclined section for the action of the bending moment and along the strip between the inclined sections for the action of the transverse force.

6.2.11 When calculating a reinforced concrete element in terms of the strength of an inclined section to the action of a transverse force, the limiting transverse force that can be perceived by the element in an inclined section should be determined as the sum of the limiting transverse forces perceived by concrete in an inclined section and transverse reinforcement crossing the inclined section.

6.2.12 When calculating a reinforced concrete element in terms of the strength of an inclined section for the action of a bending moment, the limiting moment that can be perceived by the element in the inclined section should be determined as the sum of the limiting moments perceived by the longitudinal and transverse reinforcement crossing the inclined section, relative to the axis passing through the point of application of the resultant forces in compressed zone.

6.2.13 When calculating a reinforced concrete element along a strip between inclined sections for the action of a transverse force, the limiting transverse force that can be perceived by the element should be determined based on the strength of the inclined concrete strip, which is under the influence of compressive forces along the strip and tensile forces from transverse reinforcement crossing the inclined strip.

Calculation of reinforced concrete elements by the strength of spatial sections

6.2.14 When calculating reinforced concrete elements for the strength of spatial sections, the limiting torque that can be perceived by the element should be determined as the sum of the limiting torques perceived by the longitudinal and transverse reinforcement located at each face of the element and intersecting the spatial section. In addition, it is necessary to calculate the strength of a reinforced concrete element along a concrete strip located between the spatial sections and under the influence of compressive forces along the strip and tensile forces from transverse reinforcement crossing the strip.

Calculation of reinforced concrete elements for local load action

6.2.15 When designing reinforced concrete elements for local compression, the limiting compressive force that can be taken by the element should be determined based on the resistance of concrete under the volume stress state created by the surrounding concrete and indirect reinforcement, if installed.

6.2.16 The calculation for punching is carried out for flat reinforced concrete elements (slabs) under the action of concentrated forces and moments in the punching zone. The ultimate force that can be taken by a reinforced concrete element during punching should be determined as the sum of the ultimate forces perceived by concrete and transverse reinforcement located in the punching zone.

6.3 Design of reinforced concrete elements for cracking

6.3.1 The calculation of reinforced concrete elements for the formation of normal cracks is carried out according to limit forces or according to a nonlinear deformation model. The calculation for the formation of inclined cracks is carried out according to the limiting forces.

6.3.2 The calculation for the formation of cracks in reinforced concrete elements for ultimate forces is carried out from the condition according to which the force F from external loads and influences in the considered section should not exceed the limit force F crc, which can be perceived by a reinforced concrete element during the formation of cracks

F £ F crc,ult.(6.2)

6.3.3 The ultimate force perceived by a reinforced concrete element during the formation of normal cracks should be determined based on the calculation of a reinforced concrete element as a solid body, taking into account elastic deformations in reinforcement and inelastic deformations in tensioned and compressed concrete at maximum normal tensile stresses in concrete equal to the design values of concrete tensile resistance Rbr.

6.3.4 The calculation of reinforced concrete elements for the formation of normal cracks according to a non-linear deformation model is carried out on the basis of state diagrams of reinforcement, tensioned and compressed concrete and the hypothesis of flat sections. The criterion for the formation of cracks is the achievement of limiting relative deformations in tensile concrete.

6.3.5 The ultimate force that can be taken by a reinforced concrete element during the formation of inclined cracks should be determined based on the calculation of the reinforced concrete element as a solid elastic body and the criterion of concrete strength in a plane stress state "compression-tension".

6.4 Calculation of reinforced concrete elements for crack opening

6.4.1 The calculation of reinforced concrete elements is carried out according to the opening of various types of cracks in cases where the design check for the formation of cracks shows that cracks are formed.

6.4.2 The calculation for crack opening is made from the condition according to which the crack opening width from the external load acrc should not exceed the maximum allowable crack width a crc ult

a crc £ acrc,ult. (6.3)

6.4.3 The calculation of reinforced concrete elements should be made according to the long-term and short-term opening of normal and inclined cracks.

The width of the continuous crack opening is determined by the formula

a crc = a crc 1 , (6.4)

and short opening of cracks - according to the formula

a crc = a crc 1 + a crc 2 - a crc 3 , (6.5)

where a crc 1 - width of crack opening from long-term action of permanent and temporary long-term loads;

a crc 2 - crack opening width from a short action of permanent and temporary (long-term and short-term) loads;

a crc 3 - width of crack opening from a short action of permanent and temporary long-term loads.

6.4.4 The opening width of normal cracks is determined as the product of the average relative deformations of the reinforcement in the section between the cracks and the length of this section. The average relative deformations of reinforcement between cracks are determined taking into account the work of tensioned concrete between cracks. Relative deformations of reinforcement in a crack are determined from a conditionally elastic calculation of a reinforced concrete element with cracks using the reduced modulus of deformation of compressed concrete, established taking into account the influence of inelastic deformations of concrete in a compressed zone, or from a nonlinear deformation model. The distance between cracks is determined from the condition according to which the difference in forces in the longitudinal reinforcement in the section with a crack and between the cracks must be perceived by the forces of adhesion of the reinforcement to concrete along the length of this section.

The opening width of normal cracks should be determined taking into account the nature of the load action (repeatability, duration, etc.) and the type of reinforcement profile.

6.4.5 The maximum allowable crack opening width should be set on the basis of aesthetic considerations, the presence of requirements for the permeability of structures, and also depending on the duration of the load, the type of reinforcing steel and its tendency to develop corrosion in the crack.

In this case, the maximum allowable value of the crack opening width a crc , ult should be taken no more than:

a) from the condition of reinforcement safety:

0.3 mm - with prolonged opening of cracks;

0.4 mm - with a short opening of cracks;

b) from the condition of limiting the permeability of structures:

0.2 mm - with prolonged opening of cracks;

0.3 mm - with a short opening of cracks.

For massive hydraulic structures, the maximum allowable crack opening widths are set according to the relevant regulatory documents, depending on the operating conditions of the structures and other factors, but not more than 0.5 mm.

6.5 Deformation analysis of reinforced concrete elements

6.5.1 The calculation of reinforced concrete elements by deformations is carried out from the condition according to which deflections or displacements of structures f from the action of an external load should not exceed the maximum allowable values of deflections or displacements f ult

f £ f ult. (6.6)

6.5.2 Deflections or displacements of reinforced concrete structures are determined according to the general rules of structural mechanics, depending on the bending, shear and axial deformation (rigidity) characteristics of a reinforced concrete element in sections along its length (curvature, shear angles, etc.).

6.5.3 In those cases where the deflections of reinforced concrete elements mainly depend on bending deformations, the values of deflections are determined from the stiffnesses or from the curvatures of the elements.

The stiffness of the considered section of a reinforced concrete element is determined according to the general rules of material resistance: for a section without cracks - as for a conditionally elastic solid element, and for a section with cracks - as for a conditionally elastic element with cracks (assuming a linear relationship between stresses and strains). The influence of inelastic deformations of concrete is taken into account using the reduced modulus of concrete deformations, and the influence of the work of tensile concrete between cracks is taken into account using the reduced modulus of deformations of reinforcement.

The curvature of a reinforced concrete element is determined as the ratio of the bending moment to the bending stiffness of the reinforced concrete section.

The calculation of deformations of reinforced concrete structures, taking into account cracks, is carried out in cases where the design check for the formation of cracks shows that cracks are formed. Otherwise, the deformations are calculated as for a reinforced concrete element without cracks.

The curvature and longitudinal deformations of a reinforced concrete element are also determined by a nonlinear deformation model based on the equations of equilibrium of external and internal forces acting in the normal section of the element, the hypothesis of flat sections, state diagrams of concrete and reinforcement, and average deformations of reinforcement between cracks.

6.5.4 The calculation of deformations of reinforced concrete elements should be carried out taking into account the duration of the loads established by the relevant regulatory documents.

The curvature of the elements under the action of constant and long-term loads should be determined by the formula

and curvature under the action of constant, long-term and short-term loads - according to the formula

where - the curvature of the element from the long-term action of permanent and temporary long-term loads;

The curvature of the element from a short action of permanent and temporary (long-term and short-term) loads;

The curvature of the element from a short action of permanent and temporary long-term loads.

6.5.5 Maximum allowable deflections f ult determined according to the relevant regulatory documents (SNiP 2.01.07). Under the action of permanent and temporary long-term and short-term loads, the deflection of reinforced concrete elements in all cases should not exceed 1/150 of the span and 1/75 of the cantilever extension.

7 DESIGN REQUIREMENTS

7.1 General

7.1.1 To ensure the safety and serviceability of concrete and reinforced concrete structures, in addition to the requirements for calculation, design requirements for geometric dimensions and reinforcement should also be met.

Design requirements are set for those cases when:

by calculation it is not possible to accurately and definitely fully guarantee the resistance of the structure to external loads and influences;

design requirements determine the boundary conditions within which the accepted design positions can be used;

design requirements ensure the implementation of the technology for the manufacture of concrete and reinforced concrete structures.

7.2 Requirements for geometric dimensions

The geometric dimensions of concrete and reinforced concrete structures must be at least the values that provide:

Possibility of placement of reinforcement, its anchoring and joint work with concrete, taking into account the requirements of 7.3.3-7.3.11;

Restricting the flexibility of compressed elements;

Required indicators of the quality of concrete in the structure (GOST 4.250).

7.3 Reinforcement requirements

Protective layer of concrete

7.3.1 The protective layer of concrete should provide:

Anchoring of reinforcement in concrete and the possibility of arranging joints of reinforcing elements;

Safety of fittings from environmental influences (including in the presence of aggressive influences);

Fire resistance and fire safety of structures.

7.3.2 The thickness of the concrete protective layer should be taken based on the requirements of 7.3.1, taking into account the role of reinforcement in structures (working or structural), the type of structures (columns, slabs, beams, foundation elements, walls, etc.), diameter and type of reinforcement.

The thickness of the concrete protective layer for reinforcement is taken not less than the diameter of the reinforcement and not less than 10 mm.

Minimum spacing between rebars

7.3.3 The distance between the reinforcement bars should be taken not less than the value providing:

Joint work of reinforcement with concrete;

Possibility of anchoring and joining reinforcement;

The possibility of high-quality concreting of the structure.

7.3.4 The minimum distance between the reinforcement bars in the clear should be taken depending on the diameter of the reinforcement, the size of the large concrete aggregate, the location of the reinforcement in the element in relation to the direction of concreting, the method of laying and compacting the concrete.

The distance between the reinforcement bars should be taken not less than the diameter of the reinforcement and not less than 25 mm.

Under cramped conditions, it is allowed to arrange reinforcement bars in groups of bundles (without a gap between the bars). In this case, the clear distance between the beams should be taken not less than the reduced diameter of the conditional rod, the area of which is equal to the cross-sectional area of the reinforcement beam.

Longitudinal reinforcement

7.3.5 The relative content of design longitudinal reinforcement in a reinforced concrete element (the ratio of the cross-sectional area of the reinforcement to the effective cross-sectional area of the element) should be taken not less than the value at which the element can be considered and calculated as reinforced concrete.

The minimum relative content of the working longitudinal reinforcement in a reinforced concrete element is determined depending on the nature of the reinforcement (compressed, tensioned), the nature of the element (bending, eccentrically compressed, eccentrically tensioned) and the flexibility of the eccentrically compressed element, but not less than 0.1%. For massive hydraulic structures, lower values of the relative content of reinforcement are established according to special regulatory documents.

7.3.6 The distance between the rods of the longitudinal working reinforcement should be taken taking into account the type of reinforced concrete element (columns, beams, slabs, walls), the width and height of the element section and not more than a value that ensures effective involvement of concrete in the work, uniform distribution of stresses and deformations over the width of the element section, as well as limiting the width of the crack opening between the reinforcement bars. In this case, the distance between the rods of the longitudinal working reinforcement should be taken no more than twice the height of the element section and no more than 400 mm, and in linear eccentrically compressed elements in the direction of the bending plane - no more than 500 mm. For massive hydraulic structures, large values of the distance between the rods are established according to special regulatory documents.

Transverse reinforcement

7.3.7 In reinforced concrete elements, in which the transverse force, according to the calculation, cannot be perceived only by concrete, it is necessary to install transverse reinforcement with a step of no more than a value that ensures the inclusion of transverse reinforcement in the formation and development of inclined cracks. In this case, the step of transverse reinforcement should be taken no more than half of the working height of the section of the element and no more than 300 mm.

7.3.8 In reinforced concrete elements containing design compressed longitudinal reinforcement, transverse reinforcement should be installed with a step of no more than a value that ensures the fixation of longitudinal compression reinforcement from buckling. In this case, the step of the transverse reinforcement should be taken no more than fifteen diameters of the compressed longitudinal reinforcement and not more than 500 mm, and the design of the transverse reinforcement should ensure that there is no buckling of the longitudinal reinforcement in any direction.

Anchoring and rebar connections

7.3.9 Reinforcement anchoring should be provided in reinforced concrete structures to ensure the perception of design forces in the reinforcement in the section under consideration. The length of the anchorage is determined from the condition according to which the force acting in the reinforcement must be perceived by the forces of adhesion of the reinforcement to concrete, acting along the length of the anchorage, and the resistance forces of the anchoring devices, depending on the diameter and profile of the reinforcement, the tensile strength of concrete, the thickness of the protective layer of concrete , the type of anchoring devices (rod bending, welding of transverse rods), transverse reinforcement in the anchoring zone, the nature of the force in the reinforcement (compressive or tensile) and the stress state of concrete along the anchoring length.

7.3.10 Anchoring of transverse reinforcement should be carried out by bending it and covering the longitudinal reinforcement or by welding to the longitudinal reinforcement. In this case, the diameter of the longitudinal reinforcement must be at least half the diameter of the transverse reinforcement.

7.3.11 Reinforcement overlapping (without welding) must be carried out to a length that ensures the transfer of design forces from one joined rod to another. The length of the overlap is determined by the base length of the anchorage, with additional consideration of the relative number of rods joined in one place, transverse reinforcement in the overlap joint zone, the distance between the joined rods and between the butt joints.

7.3.12 Welded fittings should be made in accordance with the relevant regulatory documents (GOST 14098, GOST 10922).

7.4 Protection of structures from the adverse effects of environmental influences

7.4.1 In cases where the required durability of structures operating under adverse environmental conditions (aggressive effects) cannot be ensured by the corrosion resistance of the structure itself, additional protection of the structure surfaces should be provided, carried out according to the instructions of SNiP 2.03.11 (treatment of the surface layer of concrete with resistance to aggressive influences of materials, application of coatings resistant to aggressive influences on the surface of the structure, etc.).

8 REQUIREMENTS FOR THE MANUFACTURE, CONSTRUCTION AND OPERATION OF CONCRETE AND REINFORCED CONCRETE STRUCTURES

8.1 Concrete

8.1.1 The selection of the composition of the concrete mixture is carried out in order to obtain concrete in the structures that meets the technical parameters established in Section 5 and adopted in the project.

The basis for the selection of the composition of concrete should be taken as the indicator of concrete that determines the type of concrete and the purpose of the structure. At the same time, other indicators of concrete quality established by the project should be provided.

The design and selection of the composition of the concrete mixture according to the required strength of concrete should be carried out in accordance with the relevant regulatory documents (GOST 27006, GOST 26633, etc.).

When selecting the composition of the concrete mixture, the required quality indicators (workability, storage, non-separation, air content and other indicators) must be ensured.

The properties of the selected concrete mixture must comply with the concrete work production technology, including the terms and conditions for concrete hardening, methods, modes of preparation and transportation of the concrete mixture, and other features of the technological process (GOST 7473, GOST 10181).

The selection of the composition of the concrete mixture should be made on the basis of the characteristics of the materials used for its preparation, including binders, aggregates, water and effective additives (modifiers) (GOST 30515, GOST 23732, GOST 8267, GOST 8736, GOST 24211).

When selecting the composition of the concrete mixture, materials should be used taking into account their environmental friendliness (restriction on the content of radionuclides, radon, toxicity, etc.).

The calculation of the main parameters of the composition of the concrete mixture is carried out using the dependencies established experimentally.

The selection of the composition of fiber-reinforced concrete should be carried out in accordance with the above requirements, taking into account the type and properties of reinforcing fibers.

8.1.2 When preparing a concrete mixture, the necessary accuracy of the dosage of the materials included in the concrete mixture and the sequence of their loading (SNiP 3.03.01) must be ensured.

Mixing of the concrete mixture should be carried out in such a way as to ensure uniform distribution of the components throughout the volume of the mixture. The duration of mixing is taken in accordance with the instructions of the enterprises - manufacturers of concrete mixing plants (factories) or set empirically.

8.1.3 Transportation of the concrete mixture should be carried out by methods and means that ensure the safety of its properties and exclude its stratification, as well as contamination by foreign materials. It is allowed to restore individual indicators of the quality of the concrete mix at the place of laying due to the introduction of chemical additives or the use of technological methods, provided that all other required quality indicators are provided.

8.1.4 The laying and compaction of concrete should be carried out in such a way that it is possible to guarantee sufficient uniformity and density of concrete in the structures that meet the requirements provided for the building structure in question (SNiP 3.03.01).

The applied methods and modes of molding should provide a given density and uniformity and are set taking into account the quality indicators of the concrete mixture, the type of structure and product, and specific engineering-geological and production conditions.

The order of concreting should be established, providing for the location of the concreting joints, taking into account the construction technology of the structure and its design features. At the same time, the necessary strength of the contact of the concrete surfaces in the concreting joint, as well as the strength of the structure, taking into account the presence of concreting joints, must be ensured.

When laying a concrete mixture at low positive and negative or elevated positive temperatures, special measures must be taken to ensure the required quality of concrete.

8.1.5 The hardening of concrete should be ensured without the use or with the use of accelerating technological influences (using heat and moisture treatment at normal or elevated pressure).

In concrete during the hardening process, the design temperature and humidity conditions should be maintained. If necessary, to create conditions that ensure an increase in the strength of concrete and a decrease in shrinkage phenomena, special protective measures should be applied. In the technological process of heat treatment of products, measures should be taken to reduce temperature differences and mutual movements between the formwork and concrete.

In massive monolithic structures, measures should be taken to reduce the effect of temperature and humidity stress fields associated with exotherm during concrete hardening on the operation of structures.

8.2 Armature

8.2.1 Reinforcement used to reinforce structures must comply with the design and requirements of the relevant standards. The fittings must be marked and appropriate certificates certifying its quality.

The conditions for storage of reinforcement and its transportation should exclude mechanical damage or plastic deformation, contamination that worsens adhesion to concrete, and corrosion damage.

8.2.2 Installation of knitted reinforcement in formwork forms should be carried out in accordance with the project. At the same time, reliable fixation of the position of the reinforcing bars with the help of special measures should be provided, ensuring the impossibility of displacement of the reinforcement during its installation and concreting of the structure.

Deviations from the design position of the reinforcement during its installation should not exceed the allowable values established by SNiP 3.03.01.

8.2.3. Welded reinforcing products (grids, frames) should be made using resistance spot welding or other methods that provide the required strength of the welded joint and do not allow a decrease in the strength of the connected reinforcing elements (GOST 14098, GOST 10922).

The installation of welded reinforcing products in the formwork should be carried out in accordance with the project. At the same time, reliable fixation of the position of reinforcing products with the help of special measures should be provided to ensure the impossibility of displacement of reinforcement products during installation and concreting.

Deviations from the design position of reinforcing products during their installation should not exceed the allowable values established by SNiP 3.03.01.

8.2.4 Bending of reinforcing bars should be carried out using special mandrels that provide the required values of the radius of curvature.

8.2.5 Welded joints of reinforcement are performed using contact, arc or bath welding. The welding method used must provide the necessary strength of the welded joint, as well as the strength and deformability of the sections of reinforcing bars adjacent to the welded joint.

8.2.6 Mechanical connections (joints) of fittings should be made using crimped and threaded couplings. The strength of the mechanical connection of the tensile reinforcement should be the same as that of the joined bars.

8.2.7 When tensioning reinforcement on stops or hardened concrete, the controlled prestress values established in the project must be ensured within the allowable deviation values established by regulatory documents or special requirements.

When releasing the tension of the reinforcement, a smooth transfer of the prestress to the concrete should be ensured.

8.3 Formwork

8.3.1 The formwork (formwork forms) must perform the following main functions: give the concrete the design shape of the structure, provide the required appearance of the outer surface of the concrete, support the structure until it gains stripping strength and, if necessary, serve as a stop when tensioning the reinforcement.

In the manufacture of structures, inventory and special, adjustable and mobile formwork are used (GOST 23478, GOST 25781).

Formwork and its fastenings should be designed and constructed in such a way that they can absorb the loads arising during the production of works, allow structures to deform freely and ensure compliance with tolerances within the limits established for a given structure or structure.

Formwork and fastenings must comply with the accepted methods of laying and compacting the concrete mixture, the conditions of prestressing, concrete hardening and heat treatment.

Removable formwork should be designed and manufactured in such a way that the structure can be stripped without damaging the concrete.

Stripping of structures should be carried out after the concrete has gained stripping strength.

Fixed formwork should be designed as an integral part of the structure.

8.4 Concrete and reinforced concrete structures

8.4.1 The manufacture of concrete and reinforced concrete structures includes formwork, reinforcement and concrete work carried out in accordance with the instructions of subsections 8.1, 8.2 and 8.3.

Finished structures must meet the requirements of the project and regulatory documents (GOST 13015.0, GOST 4.250). Deviations of geometric dimensions must be within the tolerances established for this design.

8.4.2 In concrete and reinforced concrete structures, by the beginning of their operation, the actual strength of concrete must not be lower than the required strength of concrete established in the project.

In prefabricated concrete and reinforced concrete structures, the concrete tempering strength established by the project (the strength of concrete when the structure is sent to the consumer) must be ensured, and for prestressed structures, the transfer strength established by the project (concrete strength during the release of reinforcement tension) must be ensured.

In monolithic structures, the stripping strength of concrete at the age established by the project (when removing the supporting formwork) must be ensured.

8.4.3 The lifting of structures should be carried out using special devices (mounting loops and other devices) provided for by the project. In this case, lifting conditions must be provided that exclude destruction, loss of stability, overturning, rocking and rotation of the structure.

8.4.4 The conditions of transportation, storage and storage of structures must comply with the instructions given in the project. At the same time, the safety of the structure, concrete surfaces, reinforcement outlets and mounting loops from damage must be ensured.

8.4.5 The erection of buildings and structures from prefabricated elements should be carried out in accordance with the project for the production of works, which should provide for the sequence of installation of structures and measures to ensure the required accuracy of installation, spatial invariability of structures in the process of their pre-assembly and installation in the design position, stability of structures and parts buildings or structures in the process of construction, safe working conditions.

When erecting buildings and structures from monolithic concrete, a sequence of concreting structures, removing and rearranging the formwork should be provided, ensuring strength, crack resistance and rigidity of structures during construction. In addition, it is necessary to provide for measures (constructive and technological, and, if necessary, calculation) that limit the formation and development of technological cracks.

Deviations of structures from the design position should not exceed the allowable values established for the relevant structures (columns, beams, slabs) of buildings and structures (SNiP 3.03.01).

8.4.6 Structures should be maintained in such a way that they fulfill their purpose, provided for in the project, for the entire established service life of the building or structure. It is necessary to observe the mode of operation of concrete and reinforced concrete structures of buildings and structures, which excludes a decrease in their bearing capacity, operational suitability and durability due to gross violations of normalized operating conditions (overloading of structures, failure to meet the deadlines for scheduled preventive repairs, increased aggressiveness of the environment, etc.). If damage to the structure is found during operation, which can cause a decrease in its safety and prevent its normal functioning, the measures provided for in Section 9 should be carried out.

8.5 Quality control

8.5.1 The quality control of structures should establish the compliance of the technical indicators of structures (geometric dimensions, strength indicators of concrete and reinforcement, strength, crack resistance and deformability of the structure) during their manufacture, erection and operation, as well as the parameters of technological production modes with the indicators specified in the project, regulatory documents and in technological documentation (SNiP 12-01, GOST 4.250).

Quality control methods (control rules, test methods) are regulated by the relevant standards and specifications (SNiP 3.03.01, GOST 13015.1, GOST 8829, GOST 17625, GOST 22904, GOST 23858).

8.5.2 To ensure the requirements for concrete and reinforced concrete structures, product quality control should be carried out, including input, operational, acceptance and operational control.

8.5.3 Concrete strength control should be carried out, as a rule, according to the results of testing specially made or selected control samples from the structure (GOST 10180, GOST 28570).

For monolithic structures, in addition, concrete strength control should be carried out according to the test results of control samples made at the place of laying the concrete mixture and stored under conditions identical to the hardening of concrete in the structure, or by non-destructive methods (GOST 18105, GOST 22690, GOST 17624).

Strength control should be carried out by a statistical method, taking into account the actual heterogeneity of the strength of concrete, characterized by the value of the coefficient of variation in the strength of concrete at a concrete manufacturer or at a construction site, as well as with non-destructive methods for monitoring the strength of concrete in structures.

It is allowed to use non-statistical methods of control based on the results of tests of control samples with a limited scope of controlled structures, at the initial stage of their control, with additional selective control at the site of erection of monolithic structures, as well as during control by non-destructive methods. In this case, the class of concrete is established taking into account the instructions in 9.3.4.

8.5.4 The control of frost resistance, water resistance and density of concrete should be carried out in accordance with the requirements of GOST 10060.0, GOST 12730.5, GOST 12730.1, GOST 12730.0, GOST 27005.

8.5.5 Control of reinforcement quality indicators (incoming control) should be carried out in accordance with the requirements of the standards for reinforcement and the norms for issuing acts for assessing the quality of reinforced concrete products.

Welding quality control is carried out in accordance with SNiP 3.03.01, GOST 10922, GOST 23858.

8.5.6 The assessment of the suitability of structures in terms of strength, crack resistance and deformability (serviceability) should be carried out according to the instructions of GOST 8829 by test loading the structure with a control load or by selective testing by loading to failure of individual prefabricated products taken from a batch of similar structures. The suitability of a structure can also be assessed based on the results of monitoring a set of single indicators (for prefabricated and monolithic structures) that characterize the strength of concrete, the thickness of the protective layer, the geometric dimensions of sections and structures, the location of reinforcement and the strength of welded joints, the diameter and mechanical properties of reinforcement, and the main dimensions reinforcing products and the magnitude of the reinforcement tension obtained in the process of incoming, operational and acceptance control.

8.5.7 Acceptance of concrete and reinforced concrete structures after their erection should be carried out by establishing compliance of the completed structure with the project (SNiP 3.03.01).

9 REQUIREMENTS FOR RESTORATION AND STRENGTHENING OF REINFORCED CONCRETE STRUCTURES

9.1 General

Restoration and strengthening of reinforced concrete structures should be carried out on the basis of the results of their full-scale examination, verification calculation, calculation and design of reinforced structures.

9.2 Field surveys of structures

Based on field surveys, depending on the task, the following should be established: the state of the structure, the geometric dimensions of structures, the reinforcement of structures, the strength of concrete, the type and class of reinforcement and its condition, deflections of structures, the width of cracks, their length and location, the size and nature of defects and damage , loads, static scheme of structures.

9.3 Structural verification calculations

9.3.1 Verification calculations of existing structures should be made when the loads acting on them, operating conditions and space-planning solutions change, as well as when serious defects and damages are found in the structures.

On the basis of verification calculations, the suitability of structures for operation, the need to strengthen them or reduce the operational load, or the complete unsuitability of structures, are established.

9.3.2 Verification calculations must be made on the basis of design materials, data on the manufacture and erection of structures, as well as the results of field surveys.

Design schemes for verification calculations should be adopted taking into account the established actual geometric dimensions, the actual connection and interaction of structures and structural elements, and the identified deviations during installation.

9.3.3 Verification calculations should be made for bearing capacity, deformations and crack resistance. It is allowed not to perform verification calculations for serviceability if the displacements and crack opening width in existing structures at maximum actual loads do not exceed the allowable values, and the forces in the sections of the elements from possible loads do not exceed the values of the forces from actual loads.

9.3.4 The design values of the characteristics of concrete are taken depending on the class of concrete specified in the project, or the conditional class of concrete, determined using conversion factors that provide equivalent strength according to the actual average strength of concrete obtained by testing concrete by non-destructive methods or by testing samples taken from the structure.

9.3.5 The design values of the characteristics of the reinforcement are taken depending on the class of the reinforcement specified in the project, or the conditional class of the reinforcement, determined using conversion factors that provide equivalent strength to the actual values of the average strength of the reinforcement obtained from the test data of the reinforcement samples selected from the examined structures.

In the absence of design data and the impossibility of sampling, it is allowed to set the reinforcement class according to the type of reinforcement profile, and take the design resistances 20% lower than the corresponding values of the current regulatory documents corresponding to this class.

9.3.6 When carrying out verification calculations, defects and damage to the structure identified during field surveys should be taken into account: strength reduction, local damage or destruction of concrete; breakage of reinforcement, corrosion of reinforcement, violation of anchoring and adhesion of reinforcement to concrete; dangerous formation and opening of cracks; design deviations from the project in individual structural elements and their connections.

9.3.7 Structures that do not meet the requirements of verification calculations for bearing capacity and serviceability must be strengthened or their service load must be reduced.

For structures that do not meet the requirements of verification calculations for serviceability, it is allowed not to provide for an increase or decrease in the load if the actual deflections exceed the allowable values, but do not interfere with normal operation, and also if the actual crack opening exceeds the allowable values, but does not create a risk of destruction.

9.4 Reinforcement of reinforced concrete structures

9.4.1 Reinforcement of reinforced concrete structures is carried out using steel elements, concrete and reinforced concrete, reinforcement and polymeric materials.

9.4.2 When reinforcing reinforced concrete structures, the bearing capacity of both the reinforcement elements and the reinforced structure should be taken into account. To do this, the inclusion of reinforcement elements in the work and their joint work with the reinforced structure must be ensured. For heavily damaged structures, the bearing capacity of the reinforced structure is not taken into account.

When sealing cracks with a more than permissible opening width and other concrete defects, it is necessary to ensure equal strength of the sections of structures that have undergone restoration with the main concrete.

9.4.3 The calculated values of the characteristics of the reinforcement materials are taken according to the current regulatory documents.

The design values of the characteristics of the materials of the reinforced structure are taken based on the design data, taking into account the results of the survey in accordance with the rules adopted for verification calculations.

9.4.4 The calculation of the reinforced concrete structure to be reinforced should be carried out according to the general rules for the calculation of reinforced concrete structures, taking into account the stress-strain state of the structure obtained by it before reinforcement.

APPENDIX A

Reference

SNiP 2.01.07-85*	Loads and impacts
SNiP 2.02.01-83*	Foundations of buildings and structures
SNiP 2.03.11-85	Protection of building structures against corrosion
SNiP 2.05.03-84*	Bridges and pipes
SNiP 2.06.04-82*	Loads and impacts on hydraulic structures (wave, ice and ships)
SNiP 2.06.06-85	Dams concrete and reinforced concrete
SNiP 3.03.01-87	Bearing and enclosing structures
	Organization of construction
SNiP 21-01-97*	Fire safety of buildings and structures
SNiP 23-01-99*	Building climatology
SNiP 23-02-2003	Thermal protection of buildings
	Railway and road tunnels
	Hydraulic structures. Key points
SNiP II-7-81*	Construction in seismic areas
SNiP II-23-81*	Steel structures
	SPKP. Construction. Concrete. Nomenclature of indicators
	SPKP. Construction. Concrete and reinforced concrete products and structures. Nomenclature of indicators
GOST 5781-82	Hot-rolled steel for reinforcing reinforced concrete structures. Specifications
GOST 6727-80	Cold-drawn low-carbon steel wire for reinforcing reinforced concrete structures. Specifications
GOST 7473-94	Concrete mixes. Specifications
GOST 8267-93	Crushed stone and gravel from dense rocks for construction work. Specifications
GOST 8736-93	Sand for construction work. Specifications
	Prefabricated building reinforced concrete and concrete products. Load test methods. Rules for assessing strength, stiffness and crack resistance
	Concrete. Methods for determining frost resistance. General provisions
	Concrete. Methods for determining the strength of control samples
	Concrete mixes. Test Methods
	Reinforcing steel thermomechanically hardened for reinforced concrete structures. Specifications
	Welded reinforcing and embedded products, welded fittings and embedded products of reinforced concrete structures. General specifications
GOST 12730.0-78	Concrete. General requirements for methods for determining density, porosity and water resistance
GOST 12730.1-78	Concrete. Methods for determining density
GOST 12730.5-84	Concrete. Methods for determining water resistance
GOST 13015.0-83	Prefabricated concrete and reinforced concrete structures and products. General technical requirements
GOST 13015.1-81	Prefabricated concrete and reinforced concrete structures and products. Acceptance
	Connections of welded fittings and embedded products of reinforced concrete structures. Types, design and dimensions
	Concrete. Ultrasonic strength determination method
	Reinforced concrete structures and products. Radiation method for determining the thickness of the protective layer of concrete, the size and location of the reinforcement
GOST 18105-86	Concrete. Strength control rules
GOST 20910-90	Heat resistant concrete. Specifications
	Concrete. Determination of strength by mechanical methods of non-destructive testing
	Reinforced concrete structures. Magnetic method for determining the thickness of the protective layer of concrete and the location of reinforcement
	Formwork for the construction of monolithic concrete and reinforced concrete structures. Classification and general technical requirements
GOST 23732-79	Water for concretes and mortars. Specifications
	Welded butt and tee fittings of reinforced concrete structures. Ultrasonic quality control methods. Acceptance rules
GOST 24211-91	Additives for concrete. General technical requirements
	Concrete. Classification and general technical requirements
	The concrete is silicate dense. Specifications
GOST 25246-82	Concrete is chemically resistant. Specifications
GOST 25485-89	Cellular concrete. Specifications
GOST 25781-83	Forms steel for production of reinforced concrete products. Specifications
	Concrete is light. Specifications
GOST 26633-91	Concrete is heavy and fine-grained. Specifications
GOST 27005-86	Concrete is light and cellular. Medium Density Control Rules
GOST 27006-86	Concrete. Squad selection rules
	Reliability of building structures and foundations. Basic provisions for the calculation
GOST 28570-90	Concrete. Methods for determining strength from samples taken from structures
	cements. General specifications
	Polystyrene concrete. Specifications
STO ASCHM 7-93	Rolled periodic profile from reinforcing steel. Specifications

APPENDIX B

Reference

TERMS AND DEFINITIONS

Concrete structures -	structures made of concrete without reinforcement or with reinforcement installed for structural reasons and not taken into account in the calculation, the design forces from all actions in concrete structures must be absorbed by concrete.
Reinforced concrete structures -	structures made of concrete with working and structural reinforcement (reinforced concrete structures), the design forces from all actions in reinforced concrete structures must be perceived by concrete and working reinforcement.
Steel-reinforced concrete structures -	reinforced concrete structures, including steel elements other than reinforcing steel, working together with reinforced concrete elements.
Dispersion-reinforced structures (fiber-reinforced concrete, reinforced cement) -	reinforced concrete structures, including dispersed fibers or fine-mesh nets made of thin steel wire.
Fittings working -	fittings installed according to the calculation.
Structural reinforcement -	fittings installed without design considerations.
Rebar prestressed -	reinforcement that receives initial (preliminary) stresses in the process of manufacturing structures before applying external loads during the operation stage.
Rebar anchoring -	ensuring the perception by the reinforcement of the forces acting on it by inserting it to a certain length beyond the calculated section or devices at the ends of special anchors.
Overlapped reinforcement joints -	connection of reinforcing bars along their length without welding by inserting the end of one reinforcing bar relative to the end of the other.
Working section height -	distance from the compressed face of the element to the center of gravity of the tensioned longitudinal reinforcement.
Concrete protective layer -	the thickness of the concrete layer from the element face to the nearest rebar surface.
Ultimate force-	the greatest force that can be perceived by the element, its cross section with the accepted characteristics of the materials.

APPENDIX B

Reference

EXAMPLE LIST OF CODES OF RULES DEVELOPED IN THE DEVELOPMENT OF SNiP 52-01-2003 “CONCRETE AND REINFORCED CONCRETE STRUCTURES. MAIN PROVISIONS»

1. Concrete and reinforced concrete structures without prestressing reinforcement.

2. Prestressed reinforced concrete structures.

3. Prefabricated-monolithic structures.

4. Dispersion-reinforced reinforced concrete structures.

5. Steel-reinforced concrete structures.

6. Self-stressed reinforced concrete structures.

7. Reconstruction, restoration and strengthening of concrete and reinforced concrete structures.

8. Concrete and reinforced concrete structures exposed to aggressive environments.

9. Concrete and reinforced concrete structures exposed to fire.

10. Concrete and reinforced concrete structures subjected to technological and climatic temperature and humidity influences.

11. Concrete and reinforced concrete structures exposed to repeated and dynamic loads.

12. Concrete and reinforced concrete structures made of concrete on porous aggregates and porous structure.

13. Concrete and reinforced concrete structures made of fine-grained concrete.

14. Concrete and reinforced concrete structures made of high-strength concrete (class above B60).

15. Reinforced concrete frame buildings and structures.

16. Concrete and reinforced concrete frameless buildings and structures.

17. Spatial concrete and reinforced concrete structures.

Keywords: requirements for concrete and reinforced concrete structures, standard and design values of strength and deformation characteristics of concrete, requirements for reinforcement, calculation of concrete and reinforced concrete elements for strength, cracking and deformation, protection of structures from adverse effects

Introduction

1 area of use

3 Terms and definitions

4 General requirements for concrete and reinforced concrete structures

5 Requirements for concrete and reinforcement

5.1 Requirements for concrete

5.2 Regulatory and design values of strength and deformation characteristics of concrete

5.3 Valve requirements

5.4 Regulatory and design values of strength and deformation characteristics of reinforcement

6 Requirements for the calculation of concrete and reinforced concrete structures

6.1 General

6.2 Strength design of concrete and reinforced concrete elements

6.3 Design of reinforced concrete elements for cracking

6.4 Calculation of reinforced concrete elements for crack opening

6.5 Deformation analysis of reinforced concrete elements

7 Design requirements

7.1 General

7.2 Requirements for geometric dimensions

7.3 Reinforcement requirements

7.4 Protection of structures from the adverse effects of environmental influences

8 Requirements for the manufacture, construction and operation of concrete and reinforced concrete structures

8.2 Armature

8.3 Formwork

8.4 Concrete and reinforced concrete structures

8.5 Quality control

9 Requirements for the restoration and strengthening of reinforced concrete structures

9.1 General

9.2 Field surveys of structures

9.3 Verified structural calculations

9.4 Reinforcement of reinforced concrete structures

Appendix B Reference. Terms and Definitions

MAIN PROVISIONS

UPDATED VERSION
SNiP 52-01-2003

Concrete and won't concrete construction.
Design requirements

SP 63.13330.2012

OKS 91.080.40

Foreword

The goals and principles of standardization in the Russian Federation are established by the Federal Law of December 27, 2002 N 184-FZ "On technical regulation", and the development rules - by the Decree of the Government of the Russian Federation "On the procedure for developing and approving sets of rules" of November 19, 2008 N 858.

About the set of rules

1. Performers - NIIZhB them. A.A. Gvozdev - Institute of JSC "NIC "Construction".
2. Introduced by the Technical Committee for Standardization TC 465 "Construction".
3. Prepared for approval by the Department of Architecture, Construction and Urban Policy.
4. Approved by the Order of the Ministry of Regional Development of the Russian Federation (Ministry of Regional Development of Russia) dated December 29, 2011 N 635/8 and entered into force on January 1, 2013.
5. Registered by the Federal Agency for Technical Regulation and Metrology (Rosstandart). Revision of SP 63.13330.2011 "SNiP 52-01-2003. Concrete and reinforced concrete structures. Basic provisions".

Information about changes to this set of rules is published in the annually published information index "National Standards", and the text of changes and amendments - in the monthly published information indexes "National Standards". In case of revision (replacement) or cancellation of this set of rules, a corresponding notice will be published in the monthly published information index "National Standards". Relevant information, notification and texts are also posted in the public information system - on the official website of the developer (Ministry of Regional Development of Russia) on the Internet.

Introduction

This set of rules has been developed taking into account the mandatory requirements established in the Federal Laws of December 27, 2002 N 184-FZ "On Technical Regulation", of December 30, 2009 N 384-FZ "Technical Regulations on the Safety of Buildings and Structures" and contains requirements for the calculation and design of concrete and reinforced concrete structures of industrial and civil buildings and structures.
The set of rules was developed by the team of authors of the NIIZhB named after V.I. A.A. Gvozdev - Institute of JSC "Research Center "Construction" (supervisor of the work - Doctor of Technical Sciences T.A. Mukhamediev; Doctors of Technical Sciences A.S. Zalesov, A.I. Zvezdov, E.A. Chistyakov, Candidate of Technical Sciences S.A. Zenin) with the participation of the RAASN (Doctors of Engineering Sciences V.M. Bondarenko, N.I. Karpenko, V.I. Travush) and OJSC "TsNIIpromzdaniy" (Doctors of Engineering Sciences E.N. Kodysh, N. N. Trekin, engineer I. K. Nikitin).

1 area of use

This set of rules applies to the design of concrete and reinforced concrete structures of buildings and structures for various purposes, operated in the climatic conditions of Russia (with systematic exposure to temperatures not higher than 50 ° C and not lower than minus 70 ° C), in an environment with a non-aggressive degree of impact.
The set of rules establishes requirements for the design of concrete and reinforced concrete structures made from heavy, fine-grained, light, cellular and tension concrete.
The requirements of this set of rules do not apply to the design of steel-reinforced concrete structures, fiber-reinforced concrete structures, prefabricated monolithic structures, concrete and reinforced concrete structures of hydraulic structures, bridges, pavements of roads and airfields and other special structures, as well as to structures made of concrete with an average density of less than 500 and over 2500 kg / m3, concrete polymers and polymer concretes, concretes on lime, slag and mixed binders (except for their use in cellular concrete), on gypsum and special binders, concretes on special and organic aggregates, concrete of large-pore structure.
This set of rules does not contain requirements for the design of specific structures (hollow-core slabs, undercut structures, capitals, etc.).

This set of rules uses references to the following regulatory documents:
SP 14.13330.2011 "SNiP II-7-81*. Construction in seismic regions"
SP 16.13330.2011 "SNiP II-23-81*. Steel structures"
SP 20.13330.2011 "SNiP 2.01.07-85*. Loads and impacts"
SP 22.13330.2011 "SNiP 2.02.01-83*. Foundations of buildings and structures"
SP 28.13330.2012 "SNiP 2.03.11-85. Corrosion protection of building structures"
SP 48.13330.2011 "SNiP 12-01-2004. Organization of construction"
SP 50.13330.2012 "SNiP 23-02-2003. Thermal protection of buildings"
SP 70.13330.2012 "SNiP 3.03.01-87. Bearing and enclosing structures"
SP 122.13330.2012 "SNiP 32-04-97. Railway and road tunnels"
SP 130.13330.2012 "SNiP 3.09.01-85. Manufacture of precast concrete structures and products"
SP 131.13330.2012 "SNiP 23-01-99. Construction climatology"
GOST R 52085-2003. Formwork. General specifications
GOST R 52086-2003. Formwork. Terms and Definitions
GOST R 52544-2006. Welded reinforcing rolled bars of A500C and B500C classes for reinforcing reinforced concrete structures
GOST R 53231-2008. Concrete. Strength control and assessment rules
GOST R 54257-2010. Reliability of building structures and foundations. Basic provisions and requirements
GOST 4.212-80. SPKP. Construction. Concrete. Nomenclature of indicators
GOST 535-2005. Sectioned and shaped rolled products made of carbon steel of ordinary quality. General specifications
GOST 5781-82. Hot-rolled steel for reinforcing reinforced concrete structures. Specifications
GOST 7473-94. Concrete mixes. Specifications
GOST 8267-93. Crushed stone and gravel from dense rocks for construction work. Specifications
GOST 8736-93. Sand for construction work. Specifications
GOST 8829-94. Prefabricated building reinforced concrete and concrete products. Load test methods. Rules for assessing strength, stiffness and crack resistance
GOST 10060.0-95. Concrete. Methods for determining frost resistance. Primary requirements
GOST 10180-90. Concrete. Methods for determining the strength of control samples
GOST 10181-2000. Concrete mixes. Test Methods
GOST 10884-94. Reinforcing steel thermomechanically hardened for reinforced concrete structures. Specifications
GOST 10922-90. Welded reinforcing and embedded products, welded fittings and embedded products of reinforced concrete structures. General specifications
GOST 12730.0-78. Concrete. General requirements for methods for determining density, moisture, water absorption, porosity and water resistance
GOST 12730.1-78. Concrete. Density determination method
GOST 12730.5-84. Concrete. Methods for determining water resistance
GOST 13015-2003. Reinforced concrete and concrete products for construction. General technical requirements. Rules for acceptance, labeling, transportation and storage
GOST 14098-91. Connections of welded fittings and embedded products of reinforced concrete structures. Types, design and dimensions
GOST 17624-87. Concrete. Ultrasonic strength determination method
GOST 22690-88. Concrete. Determination of strength by mechanical methods of non-destructive testing
GOST 23732-79. Water for concretes and mortars. Specifications
GOST 23858-79. Welded butt and tee fittings of reinforced concrete structures. Ultrasonic quality control methods. Acceptance rules
GOST 24211-91. Additives for concrete. General technical requirements
GOST 25192-82. Concrete. Classification and general technical requirements
GOST 25781-83. Forms steel for production of reinforced concrete products. Specifications
GOST 26633-91. Concrete is heavy and fine-grained. Specifications
GOST 27005-86. Concrete is light and cellular. Medium Density Control Rules
GOST 27006-86. Concrete. Squad selection rules
GOST 28570-90. Concrete. Methods for determining strength from samples taken from structures
GOST 30515-97. cements. General specifications.
Note. When using this set of rules, it is advisable to check the effect of reference standards and classifiers in the public information system - on the official website of the national body of the Russian Federation for standardization on the Internet or according to the annually published information index "National Standards", which was published on January 1 of the current year, and according to the corresponding monthly published information indexes published in the current year. If the referenced document is replaced (modified), then when using this set of rules, one should be guided by the replaced (modified) document. If the referenced document is canceled without replacement, the provision in which the link to it is given applies to the extent that this link is not affected.

3. Terms and definitions

In this set of rules, the following terms are used with their respective definitions:
3.1. Reinforcement anchoring: providing reinforcement with the perception of the forces acting on it by inserting it to a certain length beyond the calculated section or devices at the ends of special anchors.
3.2. Structural reinforcement: reinforcement installed without design considerations.
3.3. Prestressed reinforcement: reinforcement that receives initial (preliminary) stresses during the manufacturing process of structures prior to the application of external loads during the operation stage.
3.4. Working fittings: fittings installed according to the calculation.
3.5. Concrete cover: The thickness of the concrete cover from the element face to the nearest rebar surface.
3.6. Concrete structures: structures made of concrete without reinforcement or with reinforcement installed for structural reasons and not taken into account in the calculation; design forces from all actions in concrete structures must be absorbed by concrete.
3.7. Dispersed-reinforced structures (fiber-reinforced concrete, reinforced cement): reinforced concrete structures, including dispersed-arranged fibers or fine-mesh meshes made of thin steel wire.
3.8. Reinforced concrete structures: structures made of concrete with working and structural reinforcement (reinforced concrete structures); design forces from all impacts in reinforced concrete structures must be absorbed by concrete and working reinforcement.
3.9. Steel-reinforced concrete structures: reinforced concrete structures that include steel elements other than reinforcing steel, working together with reinforced concrete elements.
3.10. Reinforced concrete reinforcement ratio: the ratio of the cross-sectional area of the reinforcement to the effective cross-sectional area of the concrete, expressed as a percentage.
3.11. Concrete water resistance grade W: concrete permeability index, characterized by the maximum water pressure at which, under standard test conditions, water does not penetrate through the concrete sample.
3.12. Concrete grade for frost resistance F: the minimum number of freezing and thawing cycles of concrete samples established by the standards, tested according to standard basic methods, at which their original physical and mechanical properties are maintained within the normalized limits.
3.13. Concrete brand for self-stress: the value of prestress in concrete, MPa, established by the norms, created as a result of its expansion with a coefficient of longitudinal reinforcement.
3.14. Concrete grade for average density D: the density value established by the norms, in kg / m3, of concretes to which thermal insulation requirements are imposed.
3.15. Massive structure: a structure for which the ratio of the surface open to dry, m2, to its volume, m3, is equal to or less than 2.
3.16. Frost resistance of concrete: the ability of concrete to maintain physical and mechanical properties during repeated freezing and thawing, is regulated by the frost resistance grade F.
3.17. Normal section: section of an element by a plane perpendicular to its longitudinal axis.
3.18. Oblique section: section of an element by a plane inclined to its longitudinal axis and perpendicular to a vertical plane passing through the element's axis.
3.19. Density of concrete: the characteristic of concrete, equal to the ratio of its mass to volume, is regulated by the average density grade D.
3.20. Ultimate force: the greatest force that can be perceived by the element, its section, with the accepted characteristics of the materials.
3.21. Permeability of concrete: the property of concrete to pass gases or liquids through itself in the presence of a pressure gradient (regulated by the water resistance mark W) or to provide diffusion permeability of substances dissolved in water in the absence of a pressure gradient (regulated by the normalized values of current density and electric potential).
3.22. Working section height: the distance from the compressed face of the element to the center of gravity of the tensioned longitudinal reinforcement.
3.23. Concrete self-stress: the compressive stress that occurs in the concrete of the structure during hardening as a result of the expansion of the cement stone under the conditions of limitation of this expansion is regulated by the self-stress mark.
3.24. Lap joints of reinforcement: joining reinforcing bars along their length without welding by inserting the end of one reinforcing bar relative to the end of another.

4. General requirements for concrete
and reinforced concrete structures

4.1. Concrete and reinforced concrete structures of all types must meet the requirements:
for security;
by operational suitability;
for durability,
as well as additional requirements specified in the design task.
4.2. To meet the safety requirements, structures must have such initial characteristics that, under various design impacts during the construction and operation of buildings and structures, destruction of any nature or operational suitability violations associated with harm to life or health of citizens, property, environment, life are excluded. and animal and plant health.
4.3. To meet the requirements for serviceability, the structure must have such initial characteristics that, under various design impacts, crack formation or excessive opening does not occur, and also there are no excessive movements, vibrations and other damages that impede normal operation (violation of the requirements for the appearance of the structure, technological requirements for the normal operation of equipment, mechanisms, design requirements for the joint operation of elements and other requirements established during the design).
Where necessary, structures must have characteristics that meet the requirements for thermal insulation, sound insulation, biological protection and other requirements.
The requirements for the absence of cracks are imposed on reinforced concrete structures, in which, with a fully tensioned section, impermeability must be ensured (under pressure of liquid or gases, exposed to radiation, etc.), to unique structures, which are subject to increased requirements for durability, and also to structures operated in an aggressive environment in the cases specified in SP 28.13330.
In other reinforced concrete structures, the formation of cracks is allowed, and they are subject to requirements to limit the crack opening width.
4.4. To meet the durability requirements, the structure must have such initial characteristics that, for a specified long time, it would satisfy the requirements for safety and serviceability, taking into account the influence on the geometric characteristics of structures and the mechanical characteristics of materials of various design influences (long-term load effects, unfavorable climatic, technological, temperature and humidity effects, alternate freezing and thawing, aggressive effects, etc.).
4.5. Safety, serviceability, durability of concrete and reinforced concrete structures and other requirements established by the design assignment must be ensured by the following:
requirements for concrete and its components;
requirements for fittings;
requirements for structural calculations;
design requirements;
technological requirements;
operating requirements.
Requirements for loads and impacts, fire resistance limit, impermeability, frost resistance, limiting indicators of deformations (deflections, displacements, amplitude of oscillations), design values of outdoor temperature and relative humidity of the environment, protection of building structures from the effects of aggressive media, etc. are established by the relevant regulatory documents (SP 20.13330, SP 14.13330, SP 28.13330, SP 22.13330, SP 131.13330, SP 122.13330).
4.6. When designing concrete and reinforced concrete structures, the reliability of structures is established in accordance with GOST R 54257 by a semi-probabilistic calculation method by using the design values of loads and effects, the design characteristics of concrete and reinforcement (or structural steel), determined using the appropriate partial reliability factors according to the standard values of these characteristics, taking into account the level of responsibility of buildings and structures.
The normative values of loads and impacts, the values of the safety factors for the load, the safety factors for the purpose of structures, as well as the division of loads into permanent and temporary (long-term and short-term) are established by the relevant regulatory documents for building structures (SP 20.13330).
The design values of loads and impacts are taken depending on the type of design limit state and the design situation.
The level of reliability of the calculated values of the characteristics of materials is set depending on the design situation and on the danger of reaching the corresponding limit state and is regulated by the value of the reliability factors for concrete and reinforcement (or structural steel).
The calculation of concrete and reinforced concrete structures can be carried out according to a given value of reliability based on a complete probabilistic calculation if there is sufficient data on the variability of the main factors included in the design dependencies.

5. Requirements for the calculation of concrete and reinforced concrete
structures

5.1. General provisions
5.1.1. Calculations of concrete and reinforced concrete structures should be carried out in accordance with the requirements of GOST 27751 for limit states, including:
limit states of the first group, leading to complete unsuitability for the operation of structures;
limit states of the second group, which impede the normal operation of structures or reduce the durability of buildings and structures in comparison with the expected service life.
Calculations must ensure the reliability of buildings or structures throughout their entire service life, as well as during the performance of work in accordance with the requirements for them.
The calculations for the limit states of the first group include:
strength calculation;
calculation of shape stability (for thin-walled structures);
calculation for position stability (overturning, sliding, floating up).
Calculations for the strength of concrete and reinforced concrete structures should be made from the condition that forces, stresses and deformations in structures from various influences, taking into account the initial stress state (prestress, temperature and other influences), should not exceed the corresponding values established by regulatory documents.
Calculations for the stability of the shape of the structure, as well as for the stability of the position (taking into account the joint work of the structure and the base, their deformation properties, shear resistance in contact with the base and other features) should be carried out in accordance with the instructions of regulatory documents for certain types of structures.
In necessary cases, depending on the type and purpose of the structure, calculations should be made for the limit states associated with the phenomena in which it becomes necessary to stop the operation of the building and structure (excessive deformations, shifts in joints and other phenomena).
The calculations for the limit states of the second group include:
crack formation calculation;
crack opening calculation;
deformation calculation.
The calculation of concrete and reinforced concrete structures for the formation of cracks should be carried out from the condition that the forces, stresses or deformations in the structures from various influences should not exceed their respective limit values perceived by the structure during the formation of cracks.
The calculation of reinforced concrete structures for crack opening is carried out from the condition that the crack opening width in the structure from various influences should not exceed the maximum allowable values established depending on the requirements for the structure, its operating conditions, environmental impact and material characteristics, taking into account the features corrosion behavior of reinforcement.
The calculation of concrete and reinforced concrete structures for deformations should be carried out on the basis of the condition that deflections, angles of rotation, displacements and vibration amplitudes of structures from various influences should not exceed the corresponding maximum allowable values.
For structures in which cracking is not allowed, requirements for the absence of cracks must be met. In this case, the crack opening calculation is not performed.
For other structures in which cracking is allowed, a cracking analysis is performed to determine the need for a crack opening analysis and to take cracks into account in the deformation analysis.
5.1.2. The calculation of concrete and reinforced concrete structures (linear, planar, spatial, massive) according to the limit states of the first and second groups is carried out according to stresses, forces, deformations and displacements calculated from external influences in structures and systems of buildings and structures formed by them, taking into account physical nonlinearity (inelastic deformations of concrete and reinforcement), the possible formation of cracks and, if necessary, anisotropy, damage accumulation and geometric non-linearity (the effect of deformations on changes in forces in structures).
Physical nonlinearity and anisotropy should be taken into account in the constitutive relationships that relate stresses and strains (or forces and displacements), as well as in terms of strength and crack resistance of the material.
In statically indeterminate structures, one should take into account the redistribution of forces in the elements of the system due to the formation of cracks and the development of inelastic deformations in concrete and reinforcement up to the occurrence of a limit state in the element. In the absence of calculation methods that take into account the inelastic properties of reinforced concrete, as well as for preliminary calculations, taking into account the inelastic properties of reinforced concrete, forces and stresses in statically indeterminate structures and systems can be determined under the assumption of elastic operation of reinforced concrete elements. In this case, the influence of physical nonlinearity is recommended to be taken into account by adjusting the results of linear calculation based on the data of experimental studies, nonlinear modeling, calculation results of similar objects and expert assessments.
When calculating structures for strength, deformations, formation and opening of cracks based on the finite element method, the conditions of strength and crack resistance for all finite elements that make up the structure, as well as the conditions for the occurrence of excessive displacements of the structure, must be checked. When evaluating the limit state for strength, it is allowed to assume that individual finite elements are destroyed if this does not entail progressive destruction of the building or structure, and after the expiration of the considered load, the serviceability of the building or structure is maintained or can be restored.
The determination of limit forces and deformations in concrete and reinforced concrete structures should be carried out on the basis of design schemes (models) that most closely correspond to the actual physical nature of the operation of structures and materials in the considered limit state.
The bearing capacity of reinforced concrete structures capable of undergoing sufficient plastic deformation (in particular, when using reinforcement with a physical yield strength) is allowed to be determined by the limit equilibrium method.
5.1.3. When calculating concrete and reinforced concrete structures for limit states, various design situations should be considered in accordance with GOST R 54257, including the stages of manufacture, transportation, construction, operation, emergency situations, as well as fire.
5.1.4. Calculations of concrete and reinforced concrete structures should be made for all types of loads that meet the functional purpose of buildings and structures, taking into account the influence of the environment (climatic influences and water - for structures surrounded by water), and, if necessary, taking into account the effects of fire, technological temperature and humidity effects and exposure to aggressive chemical environments.
5.1.5. Calculations of concrete and reinforced concrete structures are made for the action of bending moments, longitudinal forces, transverse forces and torques, as well as for the local effect of the load.
5.1.6. When calculating the elements of prefabricated structures for the impact of forces arising during their lifting, transportation and installation, the load from the mass of the elements should be taken with a dynamic factor equal to:
1.60 - during transportation,
1.40 - during lifting and installation.
It is allowed to accept lower, justified in accordance with the established procedure, values of the dynamic coefficients, but not lower than 1.25.
5.1.7. When calculating concrete and reinforced concrete structures, one should take into account the features of the properties of various types of concrete and reinforcement, the influence of the nature of the load and the environment on them, the methods of reinforcement, the compatibility of the operation of reinforcement and concrete (in the presence and absence of adhesion of reinforcement to concrete), the technology for manufacturing structural types of reinforced concrete elements buildings and structures.
5.1.8. Calculation of prestressed structures should be carried out taking into account the initial (preliminary) stresses and strains in reinforcement and concrete, prestress losses and the specifics of prestress transfer to concrete.
5.1.9. In monolithic structures, the strength of the structure must be ensured, taking into account the working seams of concreting.
5.1.10. When calculating prefabricated structures, the strength of nodal and butt joints of prefabricated elements, carried out by connecting steel embedded parts, reinforcement outlets and concrete embedment, must be ensured.
5.1.11. When calculating flat and spatial structures subjected to force actions in two mutually perpendicular directions, separate flat or spatial small characteristic elements separated from the structure with forces acting on the sides of the element are considered. In the presence of cracks, these forces are determined taking into account the location of the cracks, the stiffness of the reinforcement (axial and tangential), the stiffness of the concrete (between the cracks and in the cracks), and other features. In the absence of cracks, the forces are determined as for a solid body.
It is allowed to determine the forces in the presence of cracks assuming the elastic operation of the reinforced concrete element.
The elements should be calculated according to the most dangerous sections located at an angle with respect to the direction of the forces acting on the element, based on calculation models that take into account the work of tension reinforcement in a crack and the work of concrete between cracks in a plane stress state.
5.1.12. The calculation of flat and spatial structures is allowed to be carried out for the structure as a whole on the basis of the limit equilibrium method, including taking into account the deformed state at the time of failure.
5.1.13. When calculating massive structures subjected to force actions in three mutually perpendicular directions, individual small volumetric characteristic elements isolated from the structure are considered with forces acting on the faces of the element. In this case, the forces should be determined on the basis of assumptions similar to those adopted for planar elements (see 5.1.11).
The calculation of the elements should be carried out according to the most dangerous sections, located at an angle with respect to the direction of the forces acting on the element, on the basis of calculation models that take into account the work of concrete and reinforcement in conditions of a three-dimensional stress state.
5.1.14. For structures of complex configuration (for example, spatial ones), in addition to calculation methods for assessing the bearing capacity, crack resistance and deformability, the results of testing physical models can also be used.
5.2. Requirements for the calculation of concrete and reinforced concrete elements for strength
5.2.1. Calculation of concrete and reinforced concrete elements for strength is carried out:
on normal sections (under the action of bending moments and longitudinal forces) - on a non-linear deformation model. For simple types of reinforced concrete structures (rectangular, tee and I-sections with reinforcement located at the upper and lower edges of the section), it is allowed to perform the calculation by limit forces;
along inclined sections (under the action of transverse forces), along spatial sections (under the action of torques), on the local action of the load (local compression, punching) - by limiting forces.
The strength calculation of short reinforced concrete elements (short consoles and other elements) is carried out on the basis of a frame-rod model.
5.2.2. The calculation of the strength of concrete and reinforced concrete elements for ultimate forces is carried out from the condition that the force from external loads and influences F in the section under consideration should not exceed the limit force that can be perceived by the element in this section

Calculation of concrete elements for strength

5.2.3. Concrete elements, depending on the conditions of their work and the requirements imposed on them, should be calculated according to normal sections for ultimate forces without taking into account (see 5.2.4) or taking into account (see 5.2.5) the concrete resistance of the tension zone.
5.2.4. Without taking into account the resistance of the concrete of the tension zone, the calculation of eccentrically compressed concrete elements is carried out at values of the eccentricity of the longitudinal force not exceeding 0.9 of the distance from the center of gravity of the section to the most compressed fiber. In this case, the limiting force that can be perceived by the element is determined by the design resistance of concrete to compression, uniformly distributed over the conditional compressed zone of the section with the center of gravity coinciding with the point of application of the longitudinal force.
For massive concrete structures, a triangular stress diagram should be taken in the compressed zone, not exceeding the calculated value of the concrete compressive strength. In this case, the eccentricity of the longitudinal force relative to the center of gravity of the section should not exceed 0.65 of the distance from the center of gravity to the most compressed concrete fiber.
5.2.5. Taking into account the resistance of concrete in the tension zone, calculation is made of eccentrically compressed concrete elements with a longitudinal force eccentricity greater than that specified in 5.2.4 of this section, bending concrete elements (which are allowed for use), as well as eccentrically compressed elements with a longitudinal force eccentricity equal to that specified in 5.2 .4, but in which the formation of cracks is not allowed under the operating conditions. In this case, the limiting force that can be perceived by the section of the element is determined as for an elastic body at maximum tensile stresses equal to the calculated value of the resistance of concrete to axial tension.
5.2.6. When designing eccentrically compressed concrete elements, the influence of buckling and random eccentricities should be taken into account.

normal sections

5.2.7. The calculation of reinforced concrete elements for ultimate forces should be carried out by determining the ultimate forces that can be perceived by concrete and reinforcement in a normal section, based on the following provisions:
tensile strength of concrete is assumed to be zero;
concrete compressive strength is represented by stresses equal to the design compressive strength of concrete and uniformly distributed over the conventional compressed zone of concrete;
tensile and compressive stresses in the reinforcement are assumed to be no more than the design tensile and compressive strength, respectively.
5.2.8. The calculation of reinforced concrete elements according to a non-linear deformation model is carried out on the basis of state diagrams of concrete and reinforcement, based on the hypothesis of flat sections. The criterion for the strength of normal sections is the achievement of limiting relative deformations in concrete or reinforcement.
5.2.9. When calculating eccentrically compressed reinforced concrete elements, random eccentricity and the effect of buckling should be taken into account.

Calculation of reinforced concrete elements by strength
inclined sections

5.2.10. The calculation of reinforced concrete elements according to the strength of inclined sections is carried out: according to the inclined section for the action of the transverse force, according to the inclined section for the action of the bending moment and along the strip between the inclined sections for the action of the transverse force.
5.2.11. When calculating a reinforced concrete element in terms of the strength of an inclined section to the action of a transverse force, the limiting transverse force that can be perceived by the element in an inclined section should be determined as the sum of the limiting transverse forces perceived by concrete in an inclined section and transverse reinforcement crossing the inclined section.
5.2.12. When calculating a reinforced concrete element in terms of the strength of an inclined section for the action of a bending moment, the limiting moment that can be perceived by the element in the inclined section should be determined as the sum of the limiting moments perceived by the longitudinal and transverse reinforcement crossing the inclined section, relative to the axis passing through the point of application of the resultant forces in compressed zone.
5.2.13. When calculating a reinforced concrete element along a strip between inclined sections for the action of a transverse force, the limiting transverse force that can be perceived by the element should be determined based on the strength of the inclined concrete strip, which is under the influence of compressive forces along the strip and tensile forces from transverse reinforcement crossing the inclined strip.

Calculation of reinforced concrete elements by strength
spatial sections

5.2.14. When calculating reinforced concrete elements for the strength of spatial sections, the limiting torque that can be perceived by the element should be determined as the sum of the limiting torques perceived by the longitudinal and transverse reinforcement located at each element face. In addition, it is necessary to calculate the strength of a reinforced concrete element along a concrete strip located between the spatial sections and under the influence of compressive forces along the strip and tensile forces from transverse reinforcement crossing the strip.

Calculation of reinforced concrete elements for local
load action

5.2.15. When designing reinforced concrete elements for local compression, the limiting compressive force that can be absorbed by the element should be determined based on the resistance of concrete under the volumetric stress state created by the surrounding concrete and indirect reinforcement, if installed.
5.2.16. The calculation for punching is carried out for flat reinforced concrete elements (slabs) under the action of concentrated forces and moments in the punching zone. The ultimate force that can be taken by a reinforced concrete element during punching should be determined as the sum of the ultimate forces perceived by concrete and transverse reinforcement located in the punching zone.
5.3. Requirements for the analysis of reinforced concrete elements for the formation of cracks
5.3.1. The calculation of reinforced concrete elements for the formation of normal cracks is carried out according to limit forces or according to a nonlinear deformation model. The calculation for the formation of inclined cracks is carried out according to the limiting forces.
5.3.2. The calculation for the formation of cracks in reinforced concrete elements according to the limit forces is carried out from the condition that the force from external loads and influences F in the considered section should not exceed the limit force that can be perceived by the reinforced concrete element during the formation of cracks.