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Code of rules SP-63.13330.2012

"SNiP 52-01-2003. CONCRETE AND REINFORCED CONCRETE STRUCTURES. MAIN PROVISIONS" Updated version of SNiP 52-01-2003

With changes:

Concrete and won't concrete construction. Design requirements

Introduction

This set of rules has been developed taking into account the mandatory requirements established in federal laws dated December 27, 2002 N 184-FZ "On technical regulation", dated 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 - Doctor of Engineering Sciences T.A. Mukhamediev; Doctors of Engineering Sciences A.S. Zalesov, A.I. Zvezdov, E.A. Chistyakov, Candidate of Engineering 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 the 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 exposure.

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, prefabricated monolithic structures, concrete and reinforced concrete structures of hydraulic structures, bridges, coatings highways and airfields and other special structures, as well as structures made from 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.

This set of rules does not contain requirements for the design of specific structures (hollow-core slabs, undercut structures, capitals, etc.).

2 Normative references

SP 2.13130.2012 "Fire protection systems. Ensuring fire resistance of protected objects" (with Amendment No. 1)

SP 14.13330.2011 "SNiP II-7-81* Construction in seismic areas"

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 Protection building structures against corrosion"

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 Production of prefabricated reinforced concrete structures and products"

SP 131.13330.2012 "SNiP 23-01-99 Building climatology"

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

GOST 18105-2010 Concrete. Strength control and assessment rules

GOST 27751-2014 Reliability of building structures and foundations. Basic provisions

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 7473-2010 Concrete mixes. Specifications.

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

GOST 8736-93 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 10181-2000 Concrete mixtures. 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 to 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, marking, transportation and storage.

GOST 14098-91 Welded fittings and embedded products of reinforced concrete structures. Types, design and dimensions.

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

GOST 22690-88 Concrete. Determination of strength by mechanical methods 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 25192-2012 Concrete. Classification and general technical requirements.

GOST 25781-83 Steel molds for manufacturing reinforced concrete products. Specifications.

GOST 26633-2012 Heavy and fine-grained concrete. Specifications.

GOST 27005-2012 Light and cellular concrete. Medium Density Control Rules.

GOST 27006-86 Concrete. Rules for the selection of compositions.

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

GOST 31108-2003 General construction cements. Specifications

GOST 31938-2012 Composite polymer rebar for reinforcing concrete structures. 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 01 of the current year , and according to the corresponding monthly published information signs 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 anchoring of reinforcement: Ensuring the perception by reinforcement of the forces acting on it by inserting it to a certain length beyond the design section or by 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 in the process of manufacturing structures before applying external loads during the operation stage.

3.4 working fittings: Fittings installed according to the calculation.

3.5 concrete cover

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 impacts in concrete structures must be taken up by the concrete.

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 absorbed by concrete and working reinforcement.

3.10 coefficient of reinforcement of reinforced concrete μ

3.11 concrete water resistance grade W

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 brand of concrete for self-stressing S p: 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 average density concrete grade D: Density value established by the norms, in kg/m 3 , of concretes subject to thermal insulation requirements.

3.15 massive structure: A structure for which the ratio of the surface open for drying, m 2 , to its volume, m 3 , 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 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 the vertical plane passing through the axis of the element.

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

3.20 limit force: The greatest force that can be perceived by the element, its cross 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 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 height of the section: The distance from the compressed edge 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 conditions of limitation of this expansion is regulated by the self-stress mark S p .

3.24 overlap joints of reinforcement: Connection of reinforcing bars along their length without welding by inserting the end of one reinforcing bar relative to the end of the other.

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 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.

4.3 To meet the requirements for serviceability, the structure must have such initial characteristics that, under various design actions, crack formation or excessive opening does not occur, and also there are no excessive movements, vibrations and other damage that hinder normal operation (violation of the requirements for appearance 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 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 design must have such initial characteristics that for a specified long time it would meet the requirements for safety and serviceability, taking into account the effect on the geometric characteristics of structures and the mechanical characteristics of materials of various design influences (long-term load effects, 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;

design requirements;

technological requirements;

operating requirements.

Requirements for loads and impacts, fire resistance limit, impermeability, frost resistance, limiting indicators of deformations (deflections, displacements, vibration amplitude), design values ​​of outdoor temperature and relative humidity of the environment, for the 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 2.13130).

4.6 When designing concrete and reinforced concrete structures, the reliability of structures is established in accordance with GOST 27751 by the semi-probabilistic method of calculation 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

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 the systems of buildings and structures formed by them, taking into account the physical non-linearity (inelastic deformations of concrete and reinforcement), possible cracking 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 27751, including the stages of manufacture, transportation, erection, 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 functional purpose 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 the effects of aggressive chemical media.

5.1.5 Calculations of concrete and reinforced concrete structures are carried out 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 take lower, justified in the prescribed manner, values ​​of the dynamism 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 various kinds concrete and reinforcement, the influence of the nature of the load and the environment on them, 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 of 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 should be ensured, taking into account the working joints of concreting.

5.1.10 When calculating prefabricated structures, the strength of nodal and butt joints of prefabricated elements, made by connecting steel embedded parts, reinforcement protrusions and embedding with concrete, must be ensured.

5.1.11 When calculating flat and three-dimensional structures subjected to forces in two mutually perpendicular directions, separate flat or three-dimensional 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 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.

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 with forces acting on the faces of the element are considered. 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.

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

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 F ult , which can be perceived by the element in this section

F≤F ult . (5.1)

Calculation of concrete elements for strength

5.2.3 Concrete elements, depending on the conditions of their operation 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 concrete in the tension zone, the calculation of eccentrically compressed concrete elements is carried out with 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 R b , uniformly distributed over the conditional compressed sectional zone 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 design value of the concrete compressive strength R b . 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 of eccentrically compressed concrete elements with an eccentricity of longitudinal force greater than specified in 5.2.4 of this section, bending concrete elements (which are allowed for use), as well as eccentrically compressed elements with an eccentricity of longitudinal force equal to specified in 5.2, 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 calculated value of the resistance of concrete to axial tension R bt .

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

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

5.2.7 Calculation of reinforced concrete elements in terms of ultimate forces should be carried out by determining the ultimate forces that can be taken 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 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 the strength of inclined sections

5.2.10 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 for 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 resultant forces in the 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 under the influence of compressive forces along the strip and tensile forces from transverse reinforcement crossing inclined strip.

Calculation of reinforced concrete elements by the strength of 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 edge of the element. 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 it is installed.

5.2.16 Punching calculation is performed for flat reinforced concrete elements (slabs) under the action of concentrated force and moment 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 non-linear deformation model. The calculation for the formation of inclined cracks is carried out according to the limiting forces.

5.3.2 Calculation of cracking of reinforced concrete elements according to 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 limiting force F crc , ult , which can be perceived by the reinforced concrete element during the formation of cracks.

F≤F crc, ult . (5.2)

5.3.3 The limiting 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 calculated resistance values concrete axial tension R bt , ser .

5.3.4 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.

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

5.4 Requirements for the analysis of reinforced concrete elements for crack opening

5.4.1 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.

5.4.2 The calculation for crack opening is made from the condition that the width of the crack opening from the external load a crc should not exceed the maximum allowable value of the crack opening width a crc , ult .

a crc ≤a crc, ult . (5.3)

5.4.3 The width of the opening 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 the 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.

5.4.4 The maximum allowable crack opening width a crc , ult should be set based on aesthetic considerations, the presence of requirements for the permeability of structures, as well as depending on the duration of the load, the type of reinforcing steel and its tendency to develop corrosion in the crack (taking into account SP 28.13330 ).

5.5 Requirements for the analysis of reinforced concrete elements for deformations

5.5.1 Deformation analysis of reinforced concrete elements is carried out from the condition that deflections or displacements of structures f due to the action of an external load should not exceed the maximum allowable values ​​of deflections or displacements f ult .

f≤f ult . (5.4)

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

5.5.3 In those cases where the deflections of reinforced concrete elements mainly depend on bending deformations, the values ​​of deflections are determined from the curvatures of the elements or from the stiffness characteristics.

The curvature of a reinforced concrete element is defined as the quotient of the bending moment divided by the bending stiffness of the reinforced concrete section.

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 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.

5.5.4 Calculation of deformations of reinforced concrete elements should be carried out taking into account the duration of the action of loads established by the relevant regulatory documents.

When calculating deflections, the stiffness of the element sections should be determined taking into account the presence or absence of cracks normal to the longitudinal axis of the element in the stretched zone of their section.

5.5.5 The values ​​of the maximum allowable deformations are taken in accordance with the instructions of 8.2.20. 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.

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

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 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 for the following documents:

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 design must have such initial characteristics that for a specified long time it would meet the requirements for safety and serviceability, taking into account the effect on the geometric characteristics of structures and the mechanical characteristics of materials of various design influences (long-term load effects, 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;

design requirements;

technological requirements;

operating requirements.

Requirements for loads and impacts, fire resistance limit, impermeability, frost resistance, limiting indicators of deformations (deflections, displacements, vibration amplitude), design values ​​of outdoor temperature and relative humidity of the environment, for the 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, SP 2.13130).

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.

(Changed edition.Change No. 2).

5 Requirements for the calculation of concrete and reinforced concrete structures

5.1 General

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 the systems of buildings and structures formed by them, taking into account the physical non-linearity (inelastic deformations of concrete and reinforcement), possible cracking 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 27751, including the stages of manufacture, transportation, construction, operation, emergency situations, as well as fire.

(Changed edition. Rev. No. 2).

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 carried out 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 (with and without adhesion of reinforcement to concrete), the technology for manufacturing structural types of reinforced concrete elements of 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 should be ensured, taking into account the working joints of concreting.

5.1.10 When calculating prefabricated structures, the strength of nodal and butt joints of prefabricated elements, made by connecting steel embedded parts, reinforcement protrusions and embedding with concrete, must be ensured.

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.

5.5 Requirements for the analysis of reinforced concrete elements for deformations

5.5.1 Deformation analysis of reinforced concrete elements is carried out from the condition that 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 u lt.

f ≤ f u lt.

5.5.2 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 characteristics of a reinforced concrete element in sections along its length (curvature, shear angles, etc.).

5.5.3 In those cases where the deflections of reinforced concrete elements mainly depend on bending deformations, the values ​​of deflections are determined from the curvatures of the elements or from the stiffness characteristics.

The curvature of a reinforced concrete element is defined as the quotient of the bending moment divided by the bending stiffness of the reinforced concrete section.

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 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.

5.5.4 Calculation of deformations of reinforced concrete elements should be carried out taking into account the duration of the action of loads established by the relevant regulatory documents.

When calculating deflections, the stiffness of the element sections should be determined taking into account the presence or absence of cracks normal to the longitudinal axis of the element in the stretched zone of their section.

5.5.5 The values ​​\u200b\u200bof the maximum allowable deformations are taken in accordance with the instructions. 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.

6 Materials for concrete and reinforced concrete structures

6.1 Concrete

6.1.1 For concrete and reinforced concrete structures designed in accordance with the requirements of this set of rules, structural concrete should be provided:

heavy medium density from 2200 to 2500 kg / m 3 inclusive;

fine-grained medium density from 1800 to 2200 kg / m 3;

cellular;

straining.

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

6.1.3 The main normalized and controlled indicators of concrete quality are:

compressive strength class IN;

axial tensile strength class Bt;

frost resistance grade F;

waterproof mark W;

medium density grade D;

self-stress grade Sp.

IN corresponds to the value of the cubic compressive strength of concrete, MPa, with a security of 0.95 (normative cubic strength).

Bt corresponds to the value of concrete strength for axial tension, MPa, with a security of 0.95 (normative strength of concrete).

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.

Concrete grade for frost resistance F corresponds to the minimum number of cycles of alternating freezing and thawing that a sample can withstand in a standard test.

Concrete grade for water resistance W corresponds to the maximum value of water pressure (in MPa⋅ 10 -1) maintained by a concrete sample during testing.

Concrete grade by average density D corresponds to the average value of the volumetric mass of concrete (kg / m 3).

The self-stressing concrete brand is the value of the prestress in concrete, MPa, created as a result of its expansion with a coefficient of longitudinal reinforcement μ = 0.01.

If necessary, additional concrete quality indicators are established related to thermal conductivity, temperature resistance, fire resistance, corrosion resistance (both concrete itself and the reinforcement in it), biological protection and other requirements for the structure (SP 50.13330, SP 28.13330).

Standardized concrete quality indicators must be ensured by the appropriate design of the composition of the concrete mixture (based on the characteristics of materials for concrete and the requirements for concrete), the technology for preparing the concrete mixture and the performance of concrete work in the manufacture (construction) of concrete and reinforced concrete products and structures. Standardized concrete quality indicators should be controlled both during the production process and directly in the fabricated structures.

The necessary normalized indicators of the quality of concrete should be established when designing concrete and reinforced concrete structures in accordance with the calculation and conditions for the manufacture and operation of structures, taking into account various environmental influences and the protective properties of concrete in relation to the accepted type of reinforcement.

Compressive strength class of concrete IN prescribed for all types of concrete and structures.

Axial tensile strength class of concrete Bt are prescribed in cases where this characteristic is of paramount importance in the operation of the structure and is controlled in production.

Concrete grade for frost resistance F prescribed for structures exposed to alternating freezing and thawing.

Concrete grade for water resistance W designate for structures to which requirements are imposed to limit water permeability.

The grade of concrete for self-stressing must be assigned to self-stressed structures, when this characteristic is taken into account in the calculation and controlled in production.

6.1.4 For concrete and reinforced concrete structures, concrete of the following classes and grades given in the tables should be provided.

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; AT 2; B2.5
D600	At 1.5; AT 2; B2.5; B3.5	B1.5; AT 2
D700	AT 2; B2.5; B3.5; AT 5	B1.5; AT 2; B2.5
D800	B2.5; B3.5; AT 5; B7.5	AT 2; B2.5; B3.5
D900	B3.5; AT 5; B7.5; AT 10	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
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%).

For above-ground structures exposed to atmospheric influences of the environment at an estimated negative temperature of the outside air in the cold period from minus 5 ° С to minus 40 ° С, a concrete grade for frost resistance of at least F75 is accepted. When the design temperature of the outside air is above minus 5 °C for above-ground structures, the frost resistance grade of concrete is not standardized.

6.1.9 The concrete grade for water resistance should be assigned depending on the requirements for structures, their mode of operation and environmental conditions in accordance with SP 28.13330.

For above-ground structures exposed to atmospheric influences at an estimated negative outdoor temperature above minus 40 ° C, as well as for the outer walls of heated buildings, the water resistance grade of concrete is not standardized.

6.1.10 The main strength characteristics of concrete are standard values:

resistance of concrete to axial compression R b, n;

resistance of concrete to axial tension Rbt,n.

The normative values ​​of concrete resistance to axial compression (prism strength) and axial tension (when assigning a concrete class for compressive strength) are taken depending on the concrete class for compressive strength B according to the table.

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 for 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 layer height 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.

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.).

In this set of rules, references are made to the following regulations SP 14.13330.2011 "SNiP II-7-81* Construction in seismic areas" 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 130.13330.20 12 "SNiP 3.09.01-85 Manufacture of prefabricated reinforced concrete structures and products” SP 131.13330.2012 “SNiP 23-01-99 Building climatology” GOST R 52085-2003 Formwork. General specifications GOST R 52086-2003 Formwork. Terms and definitions GOST R 52544-2006 Weldable rolled bars of shaped sections A 500C and B 500C for reinforcing reinforced concrete structures GOST R 53231-2008 Concrete. Rules for monitoring and assessing strength GOST R 54257-2010 Reliability of building structures and foundations. Basic provisions and requirements of GOST 4.212-80 SPKP. Construction. Concrete. Nomenclature of indicators GOST 535-2005 Sectional and shaped rolled products from 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 reinforced concrete and concrete building 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 mixtures. Test methods. GOST 10884-94 Thermomechanically hardened reinforcing steel for reinforced concrete structures. Specifications. GOST 10922-90 Welded reinforcement 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, marking, transportation and storage. GOST 14098-91 Welded fittings and embedded products of reinforced concrete structures. Types, design and dimensions. GOST 17624-87 Concrete. Ultrasonic method for determining strength. 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 for 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 Steel molds for the manufacture of reinforced concrete products. Specifications. GOST 26633-91 Heavy and fine-grained concrete. Specifications. GOST 27005-86 Light and cellular concretes. Medium Density Control Rules. GOST 27006-86 Concrete. Rules for the selection of compositions. GOST 28570-90 Concrete. Methods for determining the strength of 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 01 of the current year, and according to the corresponding monthly published information signs 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 anchoring of reinforcement: Ensuring the perception by reinforcement of the forces acting on it by inserting it to a certain length beyond the design section or by 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 in the process of manufacturing structures before applying external loads during the operation stage.

3.4 working fittings: Fittings installed according to the calculation.

3.5 concrete cover

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 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 actions in reinforced concrete structures must be taken by concrete and working reinforcement.

3.9 steel-reinforced concrete structures: Reinforced concrete structures, including steel elements other than reinforcing steel, working together with reinforced concrete elements.

3.10 coefficient of reinforcement of reinforced concrete μ

3.11 concrete water resistance grade W

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 grade for self-stressing 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 average density concrete grade D: 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 for drying, 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 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 the vertical plane passing through the axis of the element.

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

3.20 limit force: The greatest force that can be perceived by the element, its cross 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 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 height of the section: The distance from the compressed edge of the element to the center of gravity of the tensioned longitudinal reinforcement.

3.23 self-stressing of concrete: 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 of this expansion, is regulated by the self-stressing mark Sp.

3.24 overlap joints of reinforcement: Connection of reinforcing bars along their length without welding by inserting the end of one reinforcing bar relative to the end of the other.