Snip ii 23 81 steel. Design characteristics of materials and connections

STEEL STRUCTURES

SNiP II-23-81*

__________________

Introduced by TsNIISK them. Kucherenko Gosstroy USSR

Instead of SNiP II-V.3-72; SNiP II-I.9-62; CH 376-67

These standards were developed as a development of GOST 27751-88 “Reliability building structures and reasons. Basic provisions for calculations" and ST SEV 3972-83 "Reliability of building structures and foundations. Steel structures. Basic provisions for calculation."

With the entry into force of these building codes and the rules become invalid:

SNiP II-V.3-72 “Steel structures. Design standards";

changes to SNiP II-B.3-72 “Steel structures. Design standards” approved by the resolutions of the USSR State Construction Committee:

SNiP II-I.9-62 “Power transmission lines with voltage above 1 kV. Design standards" (section "Design steel structures overhead power line supports");

changes to SNiP II-I.9-62 “Power transmission lines with voltage above 1 kV. Design standards”, approved by the Decree of the USSR State Construction Committee dated April 10, 1975;

"Design Guidelines" metal structures antenna structures of communication facilities" (SN 376-67).

Amendments were made to SNiP II-23-81*, approved by resolutions of the USSR State Construction Committee No. 120 of July 25, 1984, No. 218 of December 11, 1985, No. 69 of December 29, 1986, No. 132 of July 8, 1988. , No. 121 of July 12, 1989

The main letter designations are given in the appendix. 9*.

Sections, paragraphs, tables, formulas, appendices and captions to drawings to which changes have been made are marked in these building codes and regulations with an asterisk.

Editors - engineers F.M. Shlemin, IN.P. Poddubny(Gosstroy USSR), Doctor of Engineering. science prof. IN.A. Baldin, Ph.D. tech. sciences G.E. Velsky(TsNIISK Gosstroy USSR), engineer. E.M. Bukharin(“Energosetproekt” Ministry of Energy of the USSR), engineer. N.IN. Shevelev(SKB "Mosgidrostal" Ministry of Energy of the USSR).

When using normative document it is necessary to take into account approved changes in building codes and regulations and state standards published in the Bulletin magazine construction equipment", "Collection of amendments to building codes and regulations" of the USSR State Construction Committee and the information index "USSR State Standards" of the USSR State Standard.

1. GENERAL PROVISIONS

1.1. These standards must be observed when designing steel building structures of buildings and structures for various purposes.

The standards do not apply to the design of steel structures for bridges, transport tunnels and pipes under embankments.

When designing steel structures located in special conditions operation (for example, blast furnace structures, main and process pipelines, special-purpose tanks, building structures exposed to seismic, intense temperature effects or exposure to aggressive environments, structures of marine hydraulic structures), structures unique buildings and structures, as well as special types of structures (for example, prestressed, spatial, hanging) additional requirements must be observed, reflecting the operating features of these structures, provided for by the relevant regulatory documents approved or agreed upon by the USSR State Construction Committee.

1.2. When designing steel structures, one must comply with SNiP standards for the protection of building structures from corrosion and fire safety standards for the design of buildings and structures. Increasing the thickness of rolled products and pipe walls in order to protect structures from corrosion and increase the fire resistance of structures is not allowed.

All structures must be accessible for observation, cleaning, painting, and must not retain moisture or impede ventilation. Closed profiles must be sealed.

1.3*. When designing steel structures you should:

select optimal technical and economic schemes of structures and cross-sections of elements;

use economical rolled profiles and efficient steels;

use, as a rule, unified standard or standard designs for buildings and structures;

use progressive structures (spatial systems made of standard elements; structures combining load-bearing and enclosing functions; prestressed, cable-stayed, thin-sheet and combined structures made of different steels);

provide for the manufacturability of manufacturing and installation of structures;

use designs that ensure the least labor intensity of their manufacture, transportation and installation;

provide, as a rule, for the in-line production of structures and their conveyor or large-block installation;

provide for the use of progressive types of factory connections (automatic and semi-automatic welding, flanged connections, with milled ends, bolted connections, including high-strength ones, etc.);

provide, as a rule, mounting connections with bolts, including high-strength ones; welded installation connections are allowed with appropriate justification;

comply with the requirements of state standards for structures of the corresponding type.

1.4. When designing buildings and structures, it is necessary to adopt structural schemes that ensure the strength, stability and spatial immutability of buildings and structures as a whole, as well as their individual elements during transportation, installation and operation.

1.5*. Steels and connection materials, restrictions on the use of S345T and S375T steels, as well as additional requirements for the supplied steel provided for state standards and CMEA standards or technical specifications, should be indicated in working (KM) and detailing (KMD) drawings of steel structures and in documentation for ordering materials.

Depending on the characteristics of the structures and their components, it is necessary to indicate the continuity class in accordance with GOST 27772-88 when ordering steel.

1.6*. Steel structures and their calculations must meet the requirements of GOST 27751-88 "Reliability of building structures and foundations. Basic provisions for calculation" and ST SEV 3972-83 "Reliability of building structures and foundations. Steel structures. Basic provisions for calculation."

1.7. Design schemes and basic calculation assumptions must reflect the actual operating conditions of steel structures.

Steel structures should generally be designed as unified spatial systems.

When dividing unified spatial systems into separate flat structures, the interaction of the elements with each other and with the base should be taken into account.

The choice of design schemes, as well as methods for calculating steel structures, must be made taking into account effective use COMPUTER.

1.8. Calculations of steel structures should, as a rule, be carried out taking into account inelastic deformations of steel.

For statically indeterminate structures, the calculation method for which taking into account inelastic deformations of steel has not been developed, the design forces (bending and torsional moments, longitudinal and transverse forces) should be determined under the assumption of elastic deformations of steel according to an undeformed scheme.

With an appropriate feasibility study, the calculation can be carried out using a deformed scheme that takes into account the influence of structural movements under load.

1.9. Elements of steel structures must have minimum cross-sections that meet the requirements of these standards, taking into account the range of rolled products and pipes. In composite sections established by calculation, the undervoltage should not exceed 5%.

2. MATERIALS FOR STRUCTURES AND CONNECTIONS

2.1*. Depending on the degree of responsibility of the structures of buildings and structures, as well as on the conditions of their operation, all structures are divided into four groups. Steels for steel structures of buildings and structures should be taken according to table. 50*.

Steel for structures erected in climatic regions I 1, I 2, II 2 and II 3, but operated in heated rooms, should be taken as for climatic region II 4 according to Table. 50*, with the exception of steel C245 and C275 for group 2 construction.

For flange connections and frame assemblies, rolled products according to TU 14-1-4431-88 should be used.

2.2*. For welding steel structures, the following should be used: electrodes for manual arc welding in accordance with GOST 9467-75*; welding wire according to GOST 2246-70*; fluxes according to GOST 9087-81*; carbon dioxide according to GOST 8050-85.

The welding materials and welding technology used must ensure that the tensile strength of the weld metal is not lower than the standard tensile strength value R un base metal, as well as the values ​​of hardness, impact strength and relative elongation of the metal of welded joints, established by the relevant regulatory documents.

2.3*. Castings (supporting parts, etc.) for steel structures should be designed from carbon steel grades 15L, 25L, 35L and 45L, meeting the requirements for casting groups II or III according to GOST 977-75*, as well as from gray cast iron grades SCh15, SCh20, SCh25 and SCh30, meeting the requirements of GOST 1412-85.

2.4*. For bolted connections, steel bolts and nuts that meet the requirements of GOST 1759.0-87*, GOST 1759.4-87* and GOST 1759.5-87*, and washers that meet the requirements of GOST 18123-82* should be used.

Bolts should be assigned according to the table. 57* and GOST 15589-70*, GOST 15591-70*, GOST 7796-70*, GOST 7798-70*, and when limiting joint deformations - according to GOST 7805-70*.

Nuts should be used in accordance with GOST 5915-70*: for bolts of strength classes 4.6, 4.8, 5.6 and 5.8 - nuts of strength class 4; for bolts of strength classes 6.6 and 8.8 - nuts of strength classes 5 and 6, respectively, for bolts of strength class 10.9 - nuts of strength class 8.

The following washers should be used: round washers in accordance with GOST 11371-78*, oblique washers in accordance with GOST 10906-78* and normal spring washers in accordance with GOST 6402-70*.

2.5*. The choice of steel grades for foundation bolts should be made in accordance with GOST 24379.0-80, and their design and dimensions should be taken in accordance with GOST 24379.1-80*.

Bolts (U-shaped) for fastening guy wires of antenna communication structures, as well as U-shaped and foundation bolts for supports of overhead power lines and distribution devices should be used from steel grades: 09G2S-8 and 10G2S1-8 in accordance with GOST 19281-73* with an additional requirement for impact strength at a temperature of minus 60°C is not less than 30 J/cm 2 (3 kgf × m/cm 2) in climatic region I 1; 09G2S-6 and 10G2S1-6 according to GOST 19281-73* in climatic regions I 2, II 2 and II 3; VSt3sp2 according to GOST 380-71* (since 1990 St3sp2-1 according to GOST 535-88) in all other climatic regions.

2.6*. Nuts for foundation and U-bolts should be used:

for bolts made of steel grades VSt3sp2 and 20 - strength class 4 according to GOST 1759.5-87*;

for bolts made of steel grades 09G2S and 10G2S1 - strength class not lower than 5 according to GOST 1759.5-87*. It is allowed to use nuts made of steel grades accepted for bolts.

Nuts for foundation and U-bolts with a diameter of less than 48 mm should be used in accordance with GOST 5915-70*, for bolts with a diameter of more than 48 mm - in accordance with GOST 10605-72*.

2.7*. High-strength bolts should be used in accordance with GOST 22353-77*, GOST 22356-77* and TU 14-4-1345-85; nuts and washers for them - in accordance with GOST 22354-77* and GOST 22355-77*.

2.8*. For load-bearing elements of suspended coverings, guy wires for overhead lines and outdoor switchgears, masts and towers, as well as prestressing elements in prestressed structures, the following should be used:

spiral ropes according to GOST 3062-80*; GOST 3063-80*, GOST 3064-80*;

double lay ropes according to GOST 3066-80*; GOST 3067-74*; GOST 3068-74*; GOST 3081-80*; GOST 7669-80*; GOST 14954-80*;

closed load-bearing ropes according to GOST 3090-73*; GOST 18900-73* GOST 18901-73*; GOST 18902-73*; GOST 7675-73*; GOST 7676-73*;

bundles and strands of parallel wires formed from rope wire that meets the requirements of GOST 7372-79*.

2.9. The physical characteristics of materials used for steel structures should be taken in accordance with App. 3.

3. DESIGN CHARACTERISTICS OF MATERIALS AND CONNECTIONS

3.1*. Calculated resistance of rolled products, bent profiles and pipes for various types stress states should be determined using the formulas given in table. 1*.

Table 1*

3.2*. The values ​​of reliability coefficients for rolled material, bent sections and pipes should be taken according to table. 2*.

Table 2*

GOST 19281-73* [for a circle and a square with a yield strength of over 380 MPa (39 kgf/mm 2) and dimensions not included in TU 14-1-3023-80]; GOST 8731-87; TU 14-3-567-76

The calculated resistances in tension, compression and bending of sheet, wide-band universal and shaped rolled products are given in table. 51*, pipes - in table. 51, a. The calculated resistances of bent profiles should be taken equal to the calculated resistances of the rolled sheets from which they are made, while it is possible to take into account the hardening of the rolled sheet steel in the bending zone. The design resistances of round, square and strip products should be determined according to table. 1*, taking values Ryn R un And

equal, respectively, to the yield strength and tensile strength according to TU 14-1-3023-80, GOST 380-71** (since 1990 GOST 535-88) and GOST 19281-73*.

The calculated resistance of rolled products to crushing of the end surface, local crushing in cylindrical hinges and diametric compression of the rollers are given in Table. 52*.

3.3. The calculated resistances of castings made of carbon steel and gray cast iron should be taken according to table. 53 and 54.

3.4. The calculated resistances of welded joints for various types of joints and stress states should be determined using the formulas given in Table. 3.

The calculated resistances of butt joints of elements made of steel with different standard resistances should be taken as for butt joints made of steel with a lower value of standard resistance.

The calculated resistances of the weld metal of welded joints with fillet welds are given in Table. 56.

3.5. The calculated resistances of single-bolt connections should be determined using the formulas given in table. 5*.

The calculated shear and tensile strengths of the bolts are given in Table. 58*, collapse of elements connected by bolts - in table. 59*.

3.6*. Design resistance tension of foundation bolts Rba

Rba = 0,5R. (1)

Design Tensile Strength of U-Bolts R bv, specified in clause 2.5*, should be determined by the formula

R bv = 0,45R un. (2)

The calculated tensile strength of foundation bolts is given in table. 60*.

3.7. Design tensile strength of high strength bolts Rbh should be determined by the formula

Rbh = 0,7Rbun, (3)

Where Rbun- the smallest temporary tensile strength of the bolt, taken according to the table. 61*.

3.8. Design tensile strength of high tensile steel wire Rdh, used in the form of bundles or strands, should be determined by the formula

Rdh = 0,63R un. (4)

3.9. The value of the calculated resistance (force) to tension of a steel rope should be taken equal to the value of the breaking force of the rope as a whole, established by state standards or technical specifications for steel ropes, divided by the reliability coefficient g m = 1,6.

GOSSTROY USSR

BUILDING REGULATIONS

SNiP II -23-8 1*

Part II
Design standards

Chapter 23
Steel structures

Approvedus
Decree of the USSR State Construction Committee
dated August 14, 1981 No. 144

Moscow
Central Institute
standard design

1 990

DEVELOPED BY C NIISK them. K y Cherenko with the participation of TsNIIpr oe ktsta lkonstruktsii Gosstroy I USSR, M ISI im. V.V. Kuibyshev Ministry of Higher Education of the USSR, Institute"Energosetproekt" and SKB "Moshydrostal" Ministry of Energy of the USSR.

These development standardsA We are developing GOST 27751-88"" and ST SEV 3972-83 "".

With the introduction of thisI current building codes and regulations become invalid:

SNiP II -B.3- 72 "";

changes to SNiP II -B.3- 72 " Steel structures. Design standards» , approved by resolutions of the USSR State Construction Committee:

No. 2 from 25th Varya 1980;

SNi P II -I.9-62 "" (chapter " Design of steel structures for overhead power transmission line supports»);

changes to SNiP II -I.9-62 « Power lines with voltage above 1 kV. Design standards» , approved by the resolution of the USSR State Construction Committee dated April 10 1975;

« Guidelines for the design of metal structures of antenna structures of communication facilities"(SN 376 -67).

In SNiP II-23-81 *changes were made, approved by resolutions of the USSR State Construction Committee No. 120 dated July 25, 1984, No. 218 dated December 11, 1985, No. 69 of December 29 198 6, No. 132 of July 8, 1988, No. 12 1 of July 12, 1989

The main letter designations are given in the appendix. *.

Sections, paragraphs, tables, formulas,attachments and captions to figures, V which changes have been made are marked at present their building codes are marked with an asterisk.

Editors - engineers F. M. Shle min, IN.P. P O dd dec. (Gosstroy USSR), d - r tech. science prof. IN.A. Ba ld in, Ph.D. tech. sciences G.E. Velsky(TsNIISK Gosstroy USSR), Eng. E.M. B ukharin(« Energy networkproject» Ministry of Energy of the USSR), engineer.N.IN. She ve lion(SKB "Mosgidrostal" Ministry of Energy of the USSR).

Whenl The use of a normative document should be taught s create approved changes cultural norms and rules and state standards published in the magazine"B construction equipment newsletter», « Collection of amendments to building codes and regulations» Gosstro I USSR and information index« State standards of the USSR» State Standard of the USSR.

1. GENERAL PROVISIONS

1.1. These standards arel goes to comply with P designing a hundred l nal building structures of buildings and structures for various purposes.

The standards do not apply to the design of steel structures for bridges, transport tunnels and pipes under embankments.

When designing steel structures under special operating conditions (for example, structures of blast furnaces, main and process pipelines, special-purpose tanks, building structures exposed to seismic, intense temperature effects or exposure to aggressive environments,designs of marine hydraulic structures),structures of unique buildings and structures, as well as special types of structures (for example, prestressed, spatial, hanging), additional requirements must be observed, reflecting the operating features of these structures, provided for by the relevant regulatory documents approved or agreed upon by the USSR State Construction Committee.

1.2. When designing steel structures, one must comply with SNiP standards for the protection of building structures from corrosion and fire safety standards for the design of buildings and structures. Increasing the thickness of rolled products and pipe walls in order to protect structures from corrosion and increase the fire resistance of structures is not allowed.

All structures must be accessible for observation, cleaning, painting, and must not retain moisture or impede ventilation. Closedat The molded profiles must be sealed.

1.3*. When designing maternity structures you should:

select optimal technical and economic schemes of structures and cross-sections of elements;

apply economical rolled profiles and efficient steel And;

use, as a rule, unified standard or standard designs for buildings and structures;

use progressive structures (spatial systems from standard elements; structures combining load-bearing and enclosing functions; prestressed, cable-stayeds e, thin-sheet and combined structures made of different steels);

provide for the manufacturability of manufacturing and installation of structures;

use designs that ensure the least labor intensity of their manufacture, transportation and installation;

provide, as a rule, for the in-line production of structures and their conveyor or large-block installation;

provide for the use of progressive types of factory connections (automatic and semi-automatic welding, flanged connections, with milled ends, bolted connections, including high-strength ones, etc.);

provide, as a rule, mounting connections with bolts, including high-strength ones; welded installation connections are allowed with appropriate justification;

comply with the requirements of state standards for structures of the corresponding type.

1.4. When designing buildings and structures, it is necessary to adopt structural schemes that ensure the strength, stability and spatial immutability of buildings and structures as a whole, as well as their individual elements during transportation,installation and operation.

1.5*. Steels and connection materials, restrictions on the use of steels WITH 3 45T and S 375T, as well as additional requirements for the supplied steel provided for by state standards and CMEA standards or technical specifications, should be indicated in the working conditions (CM) and de calibration (K MD) drawings of steel structures and documentation for ordering materials.

Depending on the characteristics of the structures and their components, it is necessary to indicate the continuity class in accordance with GOST 27772-88 when ordering steel.

1.6*. Steel structures and their calculations must meet the requirements of GOST 27751-88« Reliability of building structures and foundations. Basic provisions for calculation" and ST SEV 3972-83 " Reliability of building structures and foundations. Steel structures. Basic provisions for calculation».

1.7. Design schemes and basic calculation assumptions must reflect the actual operating conditions of steel structures.

Steel structures should generally,count as unified spatial systems.

When dividing unified spatial systems into separate flat structures, the interaction of the elements with each other and with the base should be taken into account.

The choice of design schemes, as well as methods for calculating steel structures, must be made taking into account the effective use of computers.

1.8. Calculations of steel structures should, as a rule, be carried out taking into account inelastic deformations of steel.

For statically indeterminate structures, the calculation method for which taking into account inelastic deformations of steel has not been developed, the design forces (bending and torsional moments, longitudinal and transverse forces) should be determined under the assumption of elastic deformations of steel according to an undeformed scheme.

With an appropriate feasibility study, the calculation can be carried out using a deformed scheme that takes into account the influence of structural movements under load.

1.9. Elements of steel structures must have minimum sections that satisfy the requirementsV to these standards, taking into account the assortment of rolled products and pipes. In composite sections established by calculation, the undervoltage should not exceed 5%.

2. MATERIALS FOR STRUCTURES AND CONNECTIONS

2.1*. Depending on the degree of responsibility of the structures of buildings and structures, as well as on the conditions of their operationat All designs are divided into four groups. Steels for steel structures of buildings and structures should be taken according to table. *.

Steels for structures erected in climatic regions I 1, I 2, II 2 and II 3 , but operated in heated premises, should be taken as for the climatic region II 4 according to table. *,with the exception of steel C245 and C275 for group 2 structures.

For flange connections and frame assemblies, rolled products should be used according to TU 14-1-4431 -88.

2.2*. For welding steel structures the following should be used:uh electrodes for manual arc welding in accordance with GOST 9467-75 *; welding wire according to GOST 2246-70*;fluxes according to GOST 9087-81 *; carbon dioxide according to GOST 8050-85.

The welding materials and welding technology used must ensure that the tensile strength of the weld metal is not lower than the standard valueI tensile strengthRunbase metal, as well as the values ​​of hardness, impact strength and relative elongation of the metal of welded joints, established by the relevant regulatory documents.

2.3*. Castings (supporting parts, etc.) for steel structures should be designed from carbon steel grades 15L, 25L, 35L and 45L, meeting the requirements for casting groups II or III according to GOST 977 -7 5 *,as well as from gray cast iron grades C Ch15 , SCh20, SCh25 and SCh30, meeting the requirements of GOST 1412-85.

2.4*. For bolted connections, steel bolts and nuts that meet the requirements of GOST 1759.0-87 *, GOST 1759.4-87 * and GOST 1759.5-87 * and washers that meet the requirements of GOST 18123-82 * should be used.

Bolts should be assigned according to the table. * and GOST 15589-70 *, GOST 15591-70 *, GOST 7796-70 *, GOST 7798-70*,and when limiting deformations of connections - according to GOST 7805-70 *.

Nuts should be used in accordance with GOST 5915-70*: for bolts of strength classes 4.6, 4.8, 5.6 and 5.8 - nuts of strength class 4; for bolts of strength classes 6.6 and 8.8 - nuts of strength classes 5 and 6, respectively, for bolts of strength class 10.9 - nuts of strength class 8.

Washers should be used: round according to GOST 11371-78*,oblique according to GOST 10906-78 * and pr and other normal according to GOST 6402-70 *.

2.5*. The choice of steel grades for foundation bolts should be made according toGOST 24379.0-80 , and their design and dimensions should be taken according toGOST 24379.1-80 *

Bolts (U-o brazn y f) for fastening guy wires of antenna communication structures, as well as U -shaped and foundation bolts for supports of overhead power lines and distribution devices should be used from steel grades: 09G2S-8 and 10G2S1-8 according to GOST 19281-73* with an additional requirement for impact strength at a temperature of minus 60 °C of at least 30 D w/cm 2 (3 kgf m/cm 2) in the climatic region I 1; 09G2S -6 and 10G2S1 -6 according to GOST 19281-73* in climatic regions I 2, II 2 and II 3 ;VSt3sp2 according to GOST 380-71*(from 199 0 g . St3sp2-1 according to GOST 535-88) in all other climatic regions.

2.6*. Nuts for foundation and U-shape s x bolts should be used:

for bolts made of steel grades VSt3sp2 and 20 - strength class 4 according to GOST 1759.5-87*;

for bolts made of steel grades 09G2S and 10G2S1 - strength class not lower than 5 according to GOST 1759.5-87 *. It is allowed to use nuts made of steel grades accepted for bolts.

Nuts for foundation and U-o brazn y x bolts with a diameter of less than 48 mm should be used in accordance with GOST 5915-70*,for bolts with a diameter of more than 48 mm - according to GOST 10605-72*.

2.7*. High-strength bolts should be used in accordance with GOST 22353-77 *, GOST 22356-77 * and TU 14-4-1345 -85; nuts and washers for them - in accordance with GOST 22354-77 * and GOST 22355-77 *.

2.8*. For load-bearing elements of suspended coverings, guy wires for overhead lines and outdoor switchgears, masts and towers, as well as prestressing elements in prestressed structures, the following should be used:

spiral ropes according to GOST 3062-80*; GOST 3063-80 *; GOST 3064-80*;

double lay ropes according to GOST 3066-80*; GOST 3067-74 *; GOST 3068-74 *; GOST 3081-80*; GOST 7669-80*;GOST 14954-80*;

closed load-bearing ropes according to GOST 3090-73*; GOST 18900-73 *; GOST 18901-73*; GOST 18902-73 *; GOST 7675-73 *; GOST 7676-73*;

bundles and strands of parallel wires formed from rope wire that meets the requirements of GOST 7372-79 *.

2.9. The physical characteristics of materials used for steel structures should be taken in accordance with App. .

3. DESIGN CHARACTERISTICS OF MATERIALS AND CONNECTIONS

3.1*. Calculated resistancesI rental, bent profiles and pipes for various types of stress states should be determined using the formulas given in table. *.

3.2*. The values ​​of reliability coefficients for rolled material, bent sections and pipes should be taken according to table. *.

Calculated resistancesI in tension, compression and bending of sheet, wide universal and shaped rolled products are given in table. *, pipes - in table., A . The calculated resistances of bent profiles should be taken equal to the calculated resistances of the rolled sheets from which they are made, while it is possible to take into account the hardening of the rolled sheet steel in the bending zone.

The design resistances of round, square and strip products should be determined according to table.*,taking valuesRyn And Run equal, respectively, to the yield strength and tensile strength according to TU 14-1-3023-80, GOST 380-71** (with 1990 GOST 535-88) and GOST 1928 1-73*.

Ta blitz 1*

The designation adopted in table. *:

γ m- to uh reliability factor for the material, determined V in accordance with paragraph.*.

(Amendment. Letter dated 11/17/2008)

Table 2*

Calculated resistance of rolled products to end surface collapse,local crushing in cylindrical hinges and diametric compression of rollers are given in table. 52*.

3.3. The calculated resistances of castings made of carbon steel and gray cast iron should be taken according to the table l. And .

3.4. The calculated resistances of welded joints for various types of joints and stress states should be determined using the formulas given in Table. .

Table 3

Note a n iya: 1.For w in s performed by manual welding, zn aspirationsRwun should be taken equal to the values ​​of temporary resistanceI rupture of weld metal, uk admonished in GOST 9467-75 *.

2. L I seams made by automatic or semi-automatic welding, aspirationsR wun should be taken according to the table.* of these standards.

3. Reliability coefficient values ​​for weld material A γ wm should be accepted A be equal: 1.25 - with valuesR wun no more than 490 M Pa (5000 kgf/cm 2);1 .35 - at valuesR wun 590 MPa (6000 kgf/cm2) or more.

The calculated resistances of butt joints of elements made of steel with different standard resistances should be taken as for butt joints of steel with a lower valueA reading normative resistance.

The calculated resistances of the weld metal of welded joints with fillet welds are given in Table. .

3.5. Design resistances of single boltss x compounds should be determined using the formulas given in table. *.

The calculated shear and tensile strengths of the bolts are given in Table.*,crushing of elements connected by bolts - in table. *.

3.6*. Design tensile strength of foundation boltsRba

Rba = 0,5 R. (1)

Design tensile strength U-o Various boltsR bv, specified in paragraph. *,should be determined by forms ule

Rbv= 0,45 Run. (2)

The calculated tensile strength of foundation bolts is given in table. *.

3.7. Design tensile strength of high strength boltsRbhshould be determined by the formula

Rbh= 0,7 Rbun, (3)

Where R bun- the smallest temporary tensile strength of the bolt, taken according to the table. *.

3.8. Design tensile strength of high tensile steel wireRdh, used in in the form of bundles or strands, should be determined by the formula

Rdh= 0,63 Run. (4)

Table 4*

* When welding with wire Cv-0 8G2S meaningR wun should be taken equal to 590 MPa (6000 kgf/cm 2 )only for fillet welds with legk f ≤8 mm V structures made of steel with a yield strength of 440 MPa (4500 kgf/cm 2)and more.

Table 5*

Note. Allowed to useI There are high-strength bolts without adjustable tension made of 40X select steel», in this case the calculated resistances IRbs AndR bt should be definedl yat as for bo l comrade class A 10.9, and the calculated resistanceRbp how dlI precision class bolts n awns B and C.

High-strength bolts according to specifications14-4- 1345 -85 can only be used when working in tension.

3.9. The value of the calculated resistance (force) to tension of the steel rope should be taken equal to the value of the breaking force of the rope as a whole, established by state standards or technical specifications for steel ropess , divided by the reliability factor γ m = 1,6.

4*. ACCOUNTING OPERATING CONDITIONS AND PURPOSE OF STRUCTURES

When calculating structures and connections, the following should be taken into account:

reliability coefficients by purpose γ n adopted in accordance with the Rules for taking into account the degree of responsibility of buildings and structures when designing structures;

reliability factor γ u = 1,3 for structural elements calculated for strength using design resistancesR u ;

working conditions coefficientsγ c and connection operating condition coefficientsγ b , accepted according to the table * and * sections of these standards for the design of buildings, structures and structures, as well as app. *.

Table 6*

DEVELOPED BY TsNIISK im. Kucherenko with the participation of TsNIIproektstalkonstruktsii of the USSR State Construction Committee, MISI named after. V.V. Kuibyshev of the USSR Ministry of Higher Education, the Energosetproekt Institute and the Mosgidrostal Design Bureau of the USSR Ministry of Energy.

These standards were developed as a development of GOST 27751-88 “Reliability of building structures and foundations. Basic provisions for calculations" and ST SEV 3972-83 "Reliability of building structures and foundations. Steel structures. Basic provisions for calculation."

With the entry into force of these building codes and regulations, the following become invalid:

• SNiP II-V.3-72 “Steel structures. Design standards";
• changes to SNiP II-B.3-72 “Steel structures. Design standards” approved by the resolutions of the USSR State Construction Committee:
  No. 150 of September 12, 1975;
  No. 94 of June 24, 1976;
  No. 211 of October 31, 1978;
  No. 250 of December 27, 1978;
  No. 2 of January 25, 1980;
  No. 104 of July 14, 1980;
  No. 130 of July 31, 1981;
• SNiP II-I.9-62 “Power transmission lines with voltage above 1 kV. Design standards" (section "Design of steel structures for overhead power transmission line supports");
• changes to SNiP II-I.9-62 “Power transmission lines with voltage above 1 kV. Design standards”, approved by the Decree of the USSR State Construction Committee dated April 10, 1975;
• “Guidelines for the design of metal structures of antenna structures of communication facilities” (SN 376-67).

Amendments were made to SNiP II-23-81*, approved by resolutions of the USSR State Construction Committee No. 120 of July 25, 1984, No. 218 of December 11, 1985, No. 69 of December 29, 1986, No. 132 of July 8, 1988. , No. 121 of July 12, 1989

The main letter designations are given in the appendix. 9*.

Sections, paragraphs, tables, formulas, appendices and captions to drawings to which changes have been made are marked in these building codes and regulations with an asterisk.

Editors - engineers F.M. Shlemin, V.P. Poddubny (Gosstroy USSR), Doctor of Engineering. science prof. V.A. Baldin, Ph.D. tech. Sciences G.E. Velsky (TsNIISK Gosstroy USSR), engineer. EAT. Bukharin (“Energosetproekt” Ministry of Energy of the USSR), engineer. N.V. Shevelev (SKB Mosgidrostal, Ministry of Energy of the USSR).

When using a regulatory document, one should take into account the approved changes to building codes and regulations and state standards published in the journal “Bulletin of Construction Equipment”, “Collection of Amendments to Construction Codes and Rules” of the USSR State Construction Committee and the information index “USSR State Standards” of the USSR State Standard.

1. General Provisions
2. Materials for structures and connections
3. Design characteristics of materials and connections
4*. Taking into account operating conditions and purpose of structures
5. Calculation of steel structure elements for axial forces and bending
6. Design lengths and maximum flexibility of steel structure elements
7. Checking the stability of walls and waist sheets of bending and compressed elements
8. Calculation of sheet structures
9. Calculation of elements of steel structures for endurance
10. Strength calculation of steel structure elements taking into account brittle fracture
11. Calculation of connections of steel structures
12. General requirements for the design of steel structures
13. Additional requirements for the design of industrial buildings and structures
14. Additional requirements for the design of residential and public buildings and structures
15*. Additional requirements for the design of overhead power line supports, structures of open switchgears and transport contact lines

GOSSTROY USSR

BUILDING REGULATIONS

SNiP II-23-81*

Part II
Design standards

Chapter 23
Steel structures

Approvedus
Decree of the USSR State Construction Committee
dated August 14, 1981 No. 144

Moscow
Central Institute
standard design

DEVELOPED BY TsNIISK im. Kucherenko with the participation of TsNIIproektstalkonstruktsii of the USSR State Construction Committee, MISI named after. V.V. Kuibyshev of the USSR Ministry of Higher Education, the Energosetproekt Institute and the Mosgidrostal Design Bureau of the USSR Ministry of Energy.

These standards were developed as a development of GOST 27751-88 “Reliability of building structures and foundations. Basic provisions for calculations" and ST SEV 3972-83 "Reliability of building structures and foundations. Steel structures. Basic provisions for calculation."

With the entry into force of these building codes and regulations, the following become invalid:

SNiP II-V.3-72 “Steel structures. Design standards";

changes to SNiP II-B.3-72 “Steel structures. Design standards” approved by the resolutions of the USSR State Construction Committee:

SNiPII-I.9-62 “Power transmission lines with voltage above 1 kV. Design standards" (section "Design of steel structures for overhead power transmission line supports");

changes to SNiP II-I.9-62 “Power transmission lines with voltage above 1 kV. Design standards”, approved by the Decree of the USSR State Construction Committee dated April 10, 1975;

“Guidelines for the design of metal structures of antenna structures of communication facilities” (SN 376-67).

Amendments were made to SNiP II-23-81*, approved by resolutions of the USSR State Construction Committee No. 120 of July 25, 1984, No. 218 of December 11, 1985, No. 69 of December 29, 1986, No. 132 of July 8, 1988, No. 121 of July 12, 1989

The main letter designations are given in the appendix. 9*.

Sections, paragraphs, tables, formulas, appendices and captions to drawings to which changes have been made are marked in these building codes and regulations with an asterisk.

Editors - engineers F.M. Shlemin, IN.P. Poddubny(Gosstroy USSR), Doctor of Engineering. science prof. IN.A. Baldin, Ph.D. tech. sciences G.E. Velsky(TsNIISK Gosstroy USSR), engineer. E.M. Bukharin(“Energosetproekt” Ministry of Energy of the USSR), engineer. N.IN. SheVelev(SKB "Mosgidrostal" Ministry of Energy of the USSR).

WhenWhen using a regulatory document, one should take into account the approved changes to building codes and regulations and state standards published in the journal “Bulletin of Construction Equipment”, “Collection of Amendments to Construction Codes and Rules” of the USSR State Construction Committee and the information index “USSR State Standards” of the USSR State Standard.

1. GENERAL PROVISIONS

1.1. These standards must be observed when designing steel building structures of buildings and structures for various purposes.

The standards do not apply to the design of steel structures for bridges, transport tunnels and pipes under embankments.

When designing steel structures under special operating conditions (for example, structures of blast furnaces, main and process pipelines, special-purpose tanks, structures of buildings exposed to seismic, intense temperature effects or exposure to aggressive environments, structures of offshore hydraulic structures), structures of unique buildings and structures, as well as special types of structures (for example, prestressed, spatial, hanging), additional requirements must be observed that reflect the operating features of these structures, provided for by the relevant regulatory documents approved or agreed upon by the USSR State Construction Committee.

1.2. When designing steel structures, one must comply with SNiP standards for the protection of building structures from corrosion and fire safety standards for the design of buildings and structures. Increasing the thickness of rolled products and pipe walls in order to protect structures from corrosion and increase the fire resistance of structures is not allowed.

All structures must be accessible for observation, cleaning, painting, and must not retain moisture or impede ventilation. Closed profiles must be sealed.

1.3*. When designing maternity structures you should:

select optimal technical and economic schemes of structures and cross-sections of elements;

use economical rolled profiles and efficient steels;

use, as a rule, unified standard or standard designs for buildings and structures;

use progressive structures (spatial systems made of standard elements; structures combining load-bearing and enclosing functions; prestressed, cable-stayed, thin-sheet and combined structures made of different steels);

provide for the manufacturability of manufacturing and installation of structures;

use designs that ensure the least labor intensity of their manufacture, transportation and installation;

provide, as a rule, for the in-line production of structures and their conveyor or large-block installation;

provide for the use of progressive types of factory connections (automatic and semi-automatic welding, flanged connections, with milled ends, bolted connections, including high-strength ones, etc.);

provide, as a rule, mounting connections with bolts, including high-strength ones; welded installation connections are allowed with appropriate justification;

comply with the requirements of state standards for structures of the corresponding type.

1.4. When designing buildings and structures, it is necessary to adopt structural schemes that ensure the strength, stability and spatial immutability of buildings and structures as a whole, as well as their individual elements during transportation, installation and operation.

1.5*. Steels and connection materials, restrictions on the use of S345T and S375T steels, as well as additional requirements for the supplied steel provided for by state standards and CMEA standards or technical specifications, should be indicated in working (DM) and detailing (DMC) drawings of steel structures and in the documentation for ordering materials.

Depending on the characteristics of the structures and their components, it is necessary to indicate the continuity class in accordance with GOST 27772-88 when ordering steel.

1.6*. Steel structures and their calculations must meet the requirements of GOST 27751-88 “Reliability of building structures and foundations. Basic provisions for calculations" and ST SEV 3972-83 "Reliability of building structures and foundations. Steel structures. Basic provisions for calculation."

1.7. Design schemes and basic calculation assumptions must reflect the actual operating conditions of steel structures.

Steel structures should generally be designed as unified spatial systems.

When dividing unified spatial systems into separate flat structures, the interaction of the elements with each other and with the base should be taken into account.

The choice of design schemes, as well as methods for calculating steel structures, must be made taking into account the effective use of computers.

1.8. Calculations of steel structures should, as a rule, be carried out taking into account inelastic deformations of steel.

For statically indeterminate structures, the calculation method for which taking into account inelastic deformations of steel has not been developed, the design forces (bending and torsional moments, longitudinal and transverse forces) should be determined under the assumption of elastic deformations of steel according to an undeformed scheme.

With an appropriate feasibility study, the calculation can be carried out using a deformed scheme that takes into account the influence of structural movements under load.

1.9. Elements of steel structures must have minimum cross-sections that meet the requirements of these standards, taking into account the range of rolled products and pipes. In composite sections established by calculation, the undervoltage should not exceed 5%.

2. MATERIALS FOR STRUCTURES AND CONNECTIONS

2.1*. Depending on the degree of responsibility of the structures of buildings and structures, as well as on the conditions of their operation, all structures are divided into four groups. Steels for steel structures of buildings and structures should be taken according to table. 50*.

Steel for structures erected in climatic regions I 1, I 2, II 2 and II 3, but operated in heated rooms, should be taken as for climatic region II 4 according to Table. 50*, with the exception of steel C245 and C275 for group 2 structures.

For flange connections and frame assemblies, rolled products according to TU 14-1-4431-88 should be used.

2.2*. For welding steel structures, the following should be used: electrodes for manual arc welding in accordance with GOST 9467-75*; welding wire according to GOST 2246-70*; fluxes according to GOST 9087-81*; carbon dioxide according to GOST 8050-85.

The welding materials and welding technology used must ensure that the tensile strength of the weld metal is not lower than the standard tensile strength value Run base metal, as well as the values ​​of hardness, impact strength and relative elongation of the metal of welded joints, established by the relevant regulatory documents.

2.3*. Castings (supporting parts, etc.) for steel structures should be designed from carbon steel grades 15L, 25L, 35L and 45L, meeting the requirements for casting groups II or III according to GOST 977-75*, as well as from gray cast iron grades SCh15, SCh20, SCh25 and SCh30, meeting the requirements of GOST 1412-85.

2.4*. For bolted connections, steel bolts and nuts that meet the requirements of GOST 1759.0-87*, GOST 1759.4-87* and GOST 1759.5-87* and washers that meet the requirements of GOST 18123-82* should be used.

Bolts should be assigned according to the table. 57* and GOST 15589-70*, GOST 15591-70*, GOST 7796-70*, GOST 7798-70*, and when limiting joint deformations - according to GOST 7805-70*.

Nuts should be used in accordance with GOST 5915-70*: for bolts of strength classes 4.6, 4.8, 5.6 and 5.8 - nuts of strength class 4; for bolts of strength classes 6.6 and 8.8 - nuts of strength classes 5 and 6, respectively, for bolts of strength class 10.9 - nuts of strength class 8.

The following washers should be used: round washers in accordance with GOST 11371-78*, oblique washers in accordance with GOST 10906-78* and normal spring washers in accordance with GOST 6402-70*.

2.5*. The choice of steel grades for foundation bolts should be made in accordance with GOST 24379.0-80, and their design and dimensions should be taken in accordance with GOST 24379.1-80*

Bolts (U-shaped) for fastening guy wires of antenna communication structures, as well as U-shaped and foundation bolts for supports of overhead power lines and distribution devices should be used from steel grades: 09G2S-8 and 10G2S1-8 according to GOST 19281-73* with an additional requirement impact strength at a temperature of minus 60 °C is not less than 30 J / cm 2 (3 kgf m/cm 2) in climatic region I 1; 09G2S-6 and 10G2S1-6 according to GOST 19281-73* in climatic regions I 2, II 2 and II 3; VSt3sp2 according to GOST 380-71* (since 1990 St3sp2-1 according to GOST 535-88) in all other climatic regions.

2.6*. Nuts for foundation and U-bolts should be used:

for bolts made of steel grades VSt3sp2 and 20 - strength class 4 according to GOST 1759.5-87*;

for bolts made of steel grades 09G2S and 10G2S1 - strength class not lower than 5 according to GOST 1759.5-87*. It is allowed to use nuts made of steel grades accepted for bolts.

Nuts for foundation and U-bolts with a diameter of less than 48 mm should be used in accordance with GOST 5915-70*, for bolts with a diameter of more than 48 mm - in accordance with GOST 10605-72*.

2.7*. High-strength bolts should be used in accordance with GOST 22353-77*, GOST 22356-77* and TU 14-4-1345-85; nuts and washers for them - in accordance with GOST 22354-77* and GOST 22355-77*.

2.8*. For load-bearing elements of suspended coverings, guy wires for overhead lines and outdoor switchgears, masts and towers, as well as prestressing elements in prestressed structures, the following should be used:

spiral ropes according to GOST 3062-80*; GOST 3063-80*; GOST 3064-80*;

double lay ropes according to GOST 3066-80*; GOST 3067-74*; GOST 3068-74*;GOST 3081-80*; GOST 7669-80*;GOST 14954-80*;

closed load-bearing ropes according to GOST 3090-73*; GOST 18900-73*;GOST 18901-73*; GOST 18902-73*; GOST 7675-73*; GOST 7676-73*;

bundles and strands of parallel wires formed from rope wire that meets the requirements of GOST 7372-79*.

2.9. The physical characteristics of materials used for steel structures should be taken in accordance with App. 3.

3. DESIGN CHARACTERISTICS OF MATERIALS AND CONNECTIONS

3.1*. The calculated resistances of rolled products, bent sections and pipes for various types of stress states should be determined using the formulas given in Table. 1*.

3.2*. The values ​​of reliability coefficients for rolled material, bent sections and pipes should be taken according to table. 2*.

The calculated resistances in tension, compression and bending of sheet, wide-band universal and shaped rolled products are given in table. 51*, pipes - in table. 51, a. The calculated resistances of bent profiles should be taken equal to the calculated resistances of the rolled sheets from which they are made, while it is possible to take into account the hardening of the rolled sheet steel in the bending zone.

The design resistances of round, square and strip products should be determined according to table. 1*, taking values Ryn And Run equal, respectively, to the yield strength and temporary resistance according to TU 14-1-3023-80, GOST 380-71** (since 1990 GOST 535-88) and GOST 19281-73*.

Table 1*

The designation adopted in table. 1*:

γ m- reliability coefficient for the material, determined in accordance with clause 3.2*.

(Amendment. Letter dated 11/17/2008)

Table 2*

TU 14-3-567-76

The calculated resistance of rolled products to crushing of the end surface, local crushing in cylindrical hinges and diametric compression of the rollers are given in Table. 52*.

3.3. The calculated resistances of castings made of carbon steel and gray cast iron should be taken according to tables 53 and 54.

3.4. The calculated resistances of welded joints for various types of joints and stress states should be determined using the formulas given in Table. 3.

For metal fusion boundaries RNotes: 1. For seams made by hand welding, the values wun

should be taken equal to the values ​​of the tensile strength of the weld metal specified in GOST 9467-75*. R wun 2. For seams made by automatic or semi-automatic welding, the values

should be taken according to Table 4* of these standards. γ wm 3. Reliability coefficient values ​​for weld material R wun should be taken equal to: 1.25 - with values R wun no more than 490 MPa (5000 kgf/cm 2); 1.35 - with values

590 MPa (6000 kgf/cm2) or more.

The calculated resistances of butt joints of elements made of steel with different standard resistances should be taken as for butt joints made of steel with a lower value of standard resistance.

The calculated resistances of the weld metal of welded joints with fillet welds are given in Table. 56.

3.5. The calculated resistances of single-bolt connections should be determined using the formulas given in table. 5*.

The calculated shear and tensile strengths of the bolts are given in Table. 58*, collapse of elements connected by bolts - in table. 59*. Rb3.6*. Design tensile strength of foundation bolts a

Rshould be determined by the formula = 0,5R. (1)

Design Tensile Strength of U-Bolts R bv, specified in clause 2.5*, should be determined by the formula

Rba= 0,45 Run. (2)

bv

3.7. Design tensile strength of high strength bolts RThe calculated tensile strength of foundation bolts is given in table. 60*. bh

RThe calculated tensile strength of foundation bolts is given in table. 60*.= 0,7 Rbun, (3)

Where should be determined by the formula R bun

- the smallest temporary tensile strength of the bolt, taken according to the table. 61*. Rdh, used in the form of bundles or strands, should be determined by the formula

Rdh= 0,63Run. (4)

Table 4*

* When welding with Sv-08G2S wire, the value RNotes: 1. For seams made by hand welding, the values should be taken equal to 590 MPa (6000 kgf/cm 2) only for fillet welds with a leg kf≤ 8 mm in structures made of steel with a yield strength of 440 MPa (4500 kgf/cm2) or more.

Table 5*

Note. It is allowed to use high-strength bolts without adjustable tension made of steel grade 40X “select”, while the calculated resistance Rbs And R bt should be determined as for bolts of class 10.9, and the design resistance Rbp as for bolts of accuracy class B and C.

High-strength bolts in accordance with TU 14-4-1345-85 may only be used when working in tension.

3.9. The value of the calculated resistance (force) to tension of a steel rope should be taken equal to the value of the breaking force of the rope as a whole, established by state standards or technical specifications for steel ropes, divided by the reliability coefficient γ m = 1,6.

4*. ACCOUNTING OPERATING CONDITIONS AND PURPOSE OF STRUCTURES

When calculating structures and connections, the following should be taken into account:

reliability coefficients by purpose γ n adopted in accordance with the Rules for taking into account the degree of responsibility of buildings and structures when designing structures;

reliability factor γ u= 1.3 for structural elements calculated for strength using design resistances Ru;

working conditions coefficients γ c and connection operating condition coefficients γ b, accepted according to the table. 6* and 35* sections of these standards for the design of buildings, structures and structures, as well as app. 4*.

Table 6*

Notes: 1. Operating conditions coefficients γ c < 1 при расчете одновременно учитывать не следует.

2. Coefficients of operating conditions, given respectively in pos. 1 and 6, in; 1 and 7; 1 and 8; 2 and 7; 2 and 8, a; 3 and 6, c, should be taken into account simultaneously in the calculation.

3. Operating conditions coefficients given in pos. 3; 4; 6, a, c; 7; 8; 9 and 10, as well as in pos. 5 and 6, b (except for butt welded joints), the considered elements should not be taken into account when calculating connections.

4. In cases not specified in these standards, the formulas should take γ s = 1.