“Organization standard BOLTED CONNECTIONS Installation rules and control, requirements...”

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Organization standard

Metal building structures

BOLTED CONNECTIONS

Installation rules and control, requirements

to the results of the work

STO NOSTROY 2.10.76-2012

OFFICIAL EDITION

Moscow 2013

NATIONAL ASSOCIATION OF BUILDERS

Organization standard

Metal building structures

BOLTED CONNECTIONS

Limited Liability Company Publishing House "BST"

Moscow 2013 STO NOSTROY 2.10.76-2012 Preface 1 DEVELOPED by the Closed Joint Stock Company “TSNIIPSK im. Melnikov"

2 SUBMITTED BY THE Committee on Industrial Construction APPROVAL to the National Association of Builders, minutes dated June 09, 2012.

No. 18 3 APPROVED AND INTRODUCED by the Decision of the Council of the National Association of Builders, Minutes dated June 22, 2012 No. 30

4 INTRODUCED FOR THE FIRST TIME

1 area of ​​use

6 Requirements for structures with bolted connections

7 Making connections using tension-controlled bolts....................................17

7.1 Requirements for mounting connections

7.2 Preparation of bolts, nuts and washers

7.3 Preparation of contact surfaces

7.4 Assembling connections

7.5 Bolt tension

8 Making bolted connections without controlled tension....................................29 9 Quality control, acceptance and sealing bolted connections.........30 10 Safe work practices

Appendix A (for reference) Execution log form installation connections on bolts with controlled tension...................................34 Appendix B (recommended) Training program for installers and technical workers for the execution and acceptance of bolted connections (20 hours). Certificate form.........................39 Appendix B (recommended) Determination of the short-circuit torque coefficient

Appendix E (informative) Typical technological execution process

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bolted connections

Bibliography

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This standard was developed within the framework of the Standardization Program of the National Association of Builders and is aimed at the implementation of the Town Planning Code Russian Federation, Federal Law dated December 27, 2002

No. 184-FZ “On technical regulation”, Federal Law of December 30, 2009 No. 384-FZ “ Technical regulations on the safety of buildings and structures", order of the Ministry of Regional Development of the Russian Federation dated December 30, 2009 No. 624 "On approval of the List of types of work for engineering surveys, preparation project documentation, construction, reconstruction, major renovation capital construction projects that influence the safety of capital construction projects.”

The standard was developed as a development of SP 70.13330.2012 “SNiP 3.03.01-87 Load-bearing and enclosing structures” regarding the installation of metal structures with bolted connections intended for buildings and structures of various levels of responsibility.

When developing the standard, the standard STO 0051-2011 “Steel construction structures” was used. Bolted connections. Manufacturing and installation", developed by ZAO TsNIIPSK im. Melnikov" and OJSC NIPI "Promstalkonstruktsiya".

The main goal of developing the standard is to create a modern regulatory framework for the implementation of installation connections of metal structures on high-strength bolts with controlled tension, as well as on bolts of all strength classes without controlled tension.

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1 area of ​​use

1.1 This standard applies to installation connections of building metal structures using bolts intended for stationary, prefabricated and mobile buildings and structures for various purposes, taking constant, temporary and special loads (moving, vibration, explosive, seismic, etc.) in climatic regions with a design temperature of up to minus 60 ° C, in areas with seismicity up to 9 points, operated in both mildly aggressive and moderately aggressive and aggressive environments using protective metal and paint coatings.

1.2 This standard establishes requirements for the execution and quality control of bolted connections when installing metal building structures using bolts, including high-strength ones, both with controlled tension and without controlled tension of the bolts.

Official publication STO NOSTROY 2.10.76-2012

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This standard uses normative references to the following standards and codes of practice:

GOST 9.30789 one system protection against corrosion and aging.

Hot zinc coatings. General requirements and control methods GOST 260184 Welding of metals. Terms and definitions of basic concepts GOST 591570* Hex nuts, accuracy class B. Design and dimensions GOST 592770* Hex nuts, accuracy class A. Design and dimensions GOST 779870* Hex head bolts, accuracy class B. Design and dimensions GOST 780570* Hex head bolts accuracy class A. Design and dimensions GOST 1060594 Hex nuts with a thread diameter over 48 mm, accuracy class B. Technical specifications GOST 1137178* Washers. Technical specifications GOST 1812382* Washers. General technical conditions GOST 1812694 Bolts and nuts with thread diameter over 48 mm. General technical conditions GOST 2007274 Heat-resistant steel. Technical specifications GOST 2311820121) Steel building structures. General technical conditions GOST 2368389 Solid petroleum paraffins. General technical conditions GOST 24379.020122) Foundation bolts. General technical conditions Introduced on the territory of the Russian Federation from July 1, 2013 instead of 1) GOST 23118–99.

Entered into force on the territory of the Russian Federation from July 1, 2013 instead of 2) GOST 24379.0–80.

STO NOSTROY 2.10.76-2012 GOST 24379.120121) Foundation bolts. Design and dimensions GOST 249972004 Calibers for metric thread. Tolerances GOST 2572683 Hand stamps, alphabetic and digital. Types and main dimensions GOST 2854890 Steel pipes. Terms and definitions GOST 8.75220112) State system ensuring uniformity of measurements. State verification scheme for instruments measuring torque and force GOST R 9.3162006 Unified system of protection against corrosion and aging. Thermal diffusion zinc coatings. General requirements and control methods GOST R 5125499 Assembly tool for standardized tightening threaded connections. Torque keys. General technical conditions GOST R 516342000 Automotive motor oils. General technical conditions GOST R 526272006 Bolts, screws and studs. Mechanical properties and test methods GOST R 526282006 Nuts. Mechanical properties and test methods GOST R 526432006 High-strength bolts and nuts and washers for metal structures. General technical conditions GOST R 526442006 High-strength bolts with a hexagonal head with an increased wrench size for metal structures. Technical specifications GOST R 526452006 High-strength hex nuts with an increased wrench size for metal structures. Technical specifications GOST R 526462006 Washers for high-strength bolts for metal structures. Technical specifications GOST R 536642009 High-strength cylindrical and conical bolts To be put into effect on the territory of the Russian Federation from July 1, 2013 instead of 1) GOST 24379.1–80.

Entered into force on the territory of the Russian Federation from January 1, 2013 instead of 2) GOST 8.54186.

STO NOSTROY 2.10.76-2012 for bridge construction, nuts and washers for them. Technical specifications GOST R ISO 899220111) Fastening products. General requirements for bolts, screws, studs and nuts GOST R ISO 160472009 Fastening products. Testing torque and pre-tightening force SP 16.13330.2011 “SNiP II-23-81* Steel structures”

SP 28.13330.2012 “SNiP 2.03.11-85 Protection steel structures from corrosion"

SP 43.13330.2011 “SNiP 2.09.03-85 Constructions of industrial enterprises”

SP 48.13330.2011 “SNiP 12-01-2004 Organization of construction”

SP 49.13330.2010 “SNiP 12-03-2001 Labor safety in construction.

Part 1. General requirements"

SP 70.13330.2012 “SNiP 3.03.01-87 Load-bearing and enclosing structures”

SP 128.13330.2012 “SNiP 2.03.06-85 Aluminum structures”

SP 131.13330.2011 “SNiP 23-01-99* Construction climatology”

Note – When using this standard, it is advisable to check the validity of the reference standards in information system common use– on the official websites of the national body of the Russian Federation for standardization and NOSTROY on the Internet or according to annually published information indexes published as of January 1 current year. If reference document replaced (changed), then when using this standard you should be guided by the new (changed) document.

If the reference document is canceled without replacement, then the provision in which a reference to it is given applies to the part that does not affect this reference.

3 Terms and definitions, designations and abbreviations

3.1 This standard uses terms in accordance with the Urban Planning Code, GOST 2601, GOST R ISO 16047, GOST 28548, SP 16.13330, Entering into force on the territory of the Russian Federation from January 1, 2013 instead of 1) GOST 1759.087.

STO NOSTROY 2.10.76-2012 SP 70.13330, SP 128.13330.

3.2 The following symbols and abbreviations are used in this standard:

KM – metal structures;

KMD – metal detailing structures;

RD – working documentation;

Ab gross cross-sectional area of ​​the bolt, mm2;

Аbn net bolt cross-sectional area, mm2;

db nominal bolt diameter, mm;

do nominal hole diameter, mm;

Kz bolt torque coefficient;

Kn reliability coefficient;

µ coefficient of friction;

length, cm;

Mz torque of bolts, N m (kgf m);

Р axial tension force of bolts, kN (tf);

Rbun is the smallest tensile strength of a bolt, N/mm2 (kgf/mm2);

g cargo weight, N (kgf);

n readings of the measuring device;

t thickness, mm.

4 Applications for bolted connections

4.1 Bolted connections may be used for all groups of steel structures specified in SP 16.13330 (Appendix B) and aluminum structures provided for in SP 128.13330.

In accordance with SP 70.13330 they are used the following types bolted connections:

STO NOSTROY 2.10.76-2012

Tension controlled bolted connections;

Bolted connections without controlled tension.

4.2 The standard covers bolted connections:

Frictional (shear-resistant), in which shear forces are perceived by friction forces acting on the contact surfaces of the connected elements as a result of the tension of the bolts to the design force;

Shear, in which shear forces are perceived by the shear resistance of the bolts, and by the resistance of the connected elements to crushing;

Friction-shear, which takes into account the entire set of resistances: bolts - shear, connected elements - crushing and friction;

Flanged, in which bolts tightened to the design strength work in tension with rigid flanges or in tension with bending with flexible flanges;

Bolt-welded, in which shear forces are perceived jointly by frictional forces from the tension of the bolts and welds;

Bolt-rivet ones, in which shear forces are perceived jointly by frictional forces from the tension of the bolts and rivets.

4.3 Frictional (shear-resistant) connections are used in structures and their elements in which residual shear movements are not permissible, operating in particularly difficult conditions or directly exposed to alternating, dynamic, vibration or moving loads, including in structures designed for fatigue.

4.4 Shear connections are used in structures operating under static loads, as well as in auxiliary structures of buildings and structures.

4.5 Friction-shear connections are used in structures operating under static loads, as well as under the influence of alternating forces, when the least of them can be transmitted by friction forces.

4.6 Flange connections are used in structures and their elements subject to tension, compression, tension with bending, local lateral forces, including moving, vibration or other types of load. NOSTROY 2.10.76-2012

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4.10 For bolted connections, as a rule, uncoated bolts, nuts and washers (hereinafter referred to as fasteners) are used.

Fasteners with protective metal coatings must be used for connections:

Structural elements with protective metal coatings applied by hot method or thermal spraying (zinc or aluminum coatings);

Elements of antenna structures, masts and power transmission line supports;

STO NOSTROY 2.10.76-2012

Structural elements operated in a moderately aggressive environment according to classification SP 28.13330, together with paint and varnish coatings;

Elements of railway, city and over-water bridges, gas pipelines;

Structural elements operating in conditions marine atmosphere.

Note – For bolted connections of structural elements operating in a marine atmosphere, it is recommended to use cadmium-coated fasteners.

4.11 In accordance with the classification of environmental aggressiveness given in SP 28.13330, thermal diffusion zinc coating according to GOST R 9.316 or hot-dip galvanizing according to GOST 9.307 using centrifugation and cutting nuts using taps as required is usually used as a protective metal coating for fasteners technical customer:

In mildly aggressive environments as a stand-alone coating;

In moderately aggressive environments - with additional paint and varnish coating.

4.12 For structures operated in slightly aggressive environments, it is allowed to use fasteners with metal coatings in accordance with GOST R ISO 8992: zinc chromated, cadmium chromated, zinc with an additional paint coating.

4.13 For structures operated in aggressive environments, bolts, nuts and washers made of corrosion-resistant, heat-resistant and heat-resistant steels in accordance with GOST R ISO 8992 are used, except for heat-resistant steels, which are used in accordance with GOST 20072.

5 Requirements for fasteners

5.1 For connections of building metal structures the following is used:

Hex head bolts of accuracy class B (normal accuracy) according to GOST 7798 or accuracy class A (increased accuracy) according to GOST 7805 with a large thread pitch, diameter from 12 to 48 mm, strength classes 5.6, 5.8, 8.8, STO NOSTROY 2.10.76 -2012 10.9, 12.9 s technical requirements according to GOST R 52627;

Hex nuts of accuracy class B (normal accuracy) according to GOST 5915 or accuracy class A (increased accuracy) according to GOST 5927, strength classes 5, 8, 10, 12 with technical requirements according to GOST R 52628;

Round washers for them in accordance with GOST 11371, version 1 accuracy class A with technical requirements in accordance with GOST 18123.

5.2 High-strength bolts, nuts and washers should be used according to GOST R 52644, GOST R 52645 and GOST R 52646 with technical requirements according to GOST R 52643 with a diameter from 16 to 48 mm of strength classes 10.9 and 12.9.

5.3 The marking of bolts and nuts must contain the mark of the manufacturer and the strength class of the product. On high-strength bolts it is additionally indicated symbol trunks, the letter S, indicating an increased size of the wrench head and the letter XL for bolts of the northern version.

5.4 According to GOST R 52627 (section 3), the bolt strength class marking consists of two numbers - the first corresponds to 1/100 of the nominal value of tensile strength, N/mm2, the second corresponds to 1/10 of the ratio of the nominal value of the yield strength to the tensile strength, %. The product of the indicated two figures corresponds to 1/10 of the nominal value of the yield strength, N/mm2.

5.5 The strength class of nuts with a nominal height equal to or greater than 0.8 d (where d is the nominal thread diameter) is indicated by a number indicating the highest strength class of the bolt with which they can be mated in a connection.

5.6 Fasteners intended for various types connections (see 4.2) are given in Table 2.

5.7 The design, dimensions and grades of steel for foundation bolts are used in accordance with GOST 24379.0 and GOST 24379.1.

5.8 Nuts for foundation bolts made of steel grade VSt3sp2 and grade 20, with a diameter of up to 48 mm, should be taken in accordance with GOST 5915 strength class 4; for foundation bolts made of steel grades 09G2S and 10G2S1 - strength class and certificate of the established form indicating the results of acceptance tests and after input control for compliance with the requirements of GOST R 52643, GOST R 52644, GOST R 52645 and GOST R 52646 (see 7.1.4).

5.12 It is allowed to use high-strength bolts of the strength class

10.9 with guaranteed tightening torque of threaded connections according to TU 1282-162-02494680-2007.

6 Requirements for structures with bolted connections

6.1 Metal structures with bolted connections are manufactured in accordance with the working documentation KM (metal structures) and KMD (metal detailing structures), technological documentation of the manufacturer, SP 53-101-98, GOST 23118, taking into account the requirements of SP 70.13330, SP 28.13330 .

6.2 Installation of metal structures is carried out in accordance with the requirements of KM and KMD, SP 70.13330, sections 7 and 8 of this standard.

6.3 In the general data, explanatory note or on the CM drawings, as a rule, the following should be indicated:

Types of connections;

Nominal diameters of holes and bolts;

Standards for bolts, nuts and washers;

Strength classes of bolts and nuts;

Axial tension forces of bolts;

Method for regulating and monitoring axial tension forces of bolts;

Method for preparing contact surfaces indicating the calculated value of the friction coefficient;

Parts and areas that are not subject to priming or painting at the enterprise that manufactures metal structures;

Additional requirements for the manufacture and installation of metal structures STO NOSTROY 2.10.76-2012;

Regulatory documents for the manufacture and installation of metal structures;

Instructions for anti-corrosion protection of metal structures.

6.4 Depending on the degree of responsibility of individual groups of steel structures of buildings and structures, as well as on the conditions of their operation and the climatic region of construction, sheet and shaped rolled steel should be used for structural elements with bolted connections in accordance with SP 16.13330 (Appendix B).

6.5 For aluminum structures, aluminum grades and conditions must be used in accordance with SP 128.13330.

6.6 For flanges subject to tension, bending or their combined action, sheet steel with guaranteed mechanical properties in the direction of the rolled thickness should be used, taking into account the requirements of SP 16.13330 (section 13 and clause 15.9).

6.7 The welding technology used and welding materials in accordance with SP 16.13330 (clause 5.4) must provide values ​​of the tensile strength of the metal of the welds not lower than the standard values ​​of the tensile strength Run of the base metal.

6.8 Bolts, nuts and washers intended for installation are usually supplied by manufacturers of metal structures. Approximate consumption fasteners are given in VSN 428-81.

6.9 When manufacturing structures at the installation site, the rolled steel used, before being put into production, must be checked for compliance with the accompanying documentation, the absence of unacceptable damage, local dents, cracks, delaminations, and deviations from geometric dimensions.

6.10 Cutting of shaped and sheet products is permitted both mechanically and thermally. In this case, the edges of structural elements working in tension, as well as those made of steel with a standard STO NOSTROY 2.10.76-2012 yield limit of over 350 MPa, must be subjected to machining to a depth of at least 20% of the element thickness.

6.11 The diameters of holes for bolted installation connections must comply with the requirements of the KM.

6.12 Holes should be formed by drilling on production lines, numerically controlled machines, using jigs, and in the absence of equipment, using templates, ensuring accuracy in accordance with that specified in the CM or this standard. For non-design structural bolted connections, the formation of holes according to the marking is allowed.

6.13 In non-design connections, the formation of holes by punching is allowed for steels with a standard yield strength of up to 350 MPa with a ratio of metal thickness t and hole diameter do of no more than 0.7 at t 20 mm.

6.14 In design connections, punching holes of smaller diameter is allowed, but not more than 0.75 do, with a metal thickness of no more than 0.8 do, followed by drilling to the design diameter do.

6.15 Maximum deviation the diameter of the holes should not exceed:

0.6 mm for holes up to 28 mm in diameter;

0.8 mm for holes with a diameter over 28 mm.

6.16 Maximum deviations between the centers of holes are established by the working documentation, based on the condition of assembled structures during installation.

6.17 In the absence of instructions in the working documentation, the maximum deviations in dimensions between the centers of holes in a group are set equal to ± 1.0 mm, including diagonally, between groups of ± 0.5 mm for each meter of distance between them.

6.18 The maximum deviation in the dimensions of the connected elements should be no more than ± 3.0 mm at 6 m and ± 0.5 mm per meter of length at 6 m.

6.19 The thickness of the linings, as a rule, should not exceed:

For M12 bolts – 12 mm;

For M16 bolts – 16 mm;

STO NOSTROY 2.10.76-2012

For M20 bolts – 20 mm;

For M24 bolts – 30 mm;

For M27 bolts – 35 mm;

For bolts M30 - 40 mm.

If it is necessary to use linings of greater thickness, double-layer linings or larger diameter bolts should be used.

For M12 bolts – 96 mm;

For M16 bolts – 128 mm;

For M20 bolts – 160 mm;

For M24 bolts – 192 mm;

For M27 bolts – 216 mm;

For M30 bolts – 240 mm.

6.21 For flanged connections, the thickness of the flanges should be:

For M20 bolts from 20 to 35 mm;

For M24 bolts from 25 to 45 mm;

For M27 bolts from 30 to 55 mm.

6.22 Assembly and welding of structural elements with flange connections should be performed in jigs. Base surfaces of conductors and external surfaces flanges must be milled after welding. The tangent of the flange surface deflection angle should not exceed 0.0007 in each of the two planes.

6.23 Dispatch marks of structures must be primed or painted (as agreed with the technical customer) with the exception of the contact surfaces of friction and friction-shear joints, as well as the contact surfaces of flanges if this is specified in the working documentation.

6.24 Roll scale on the contact surfaces of friction and friction-shear joints with a thickness of more than 0.05 mm must be removed mechanically.

6.25 Control assembly of structures with bolted connections is carried out at the manufacturer in cases where this is specified in the working documentation or at the request of the technical customer.

6.26 Control assembly is carried out in accordance with the requirements of the working documentation. The discrepancy between the holes (blackness) is checked with a gauge with a diameter 0.5 mm larger than the nominal diameter of the bolt. The gauge must fit into 100% of the holes in each connection.

6.27 The gaps between the connected elements are controlled with a 0.3 mm thick feeler gauge, and between the flanges - with a 0.1 mm thick feeler gauge. The probe should not penetrate into the area limited by a radius of 1.3 do from the bolt axis after tightening all bolts of the connection to the design force, where do is the diameter of the hole.

7 Making connections using tension-controlled bolts

7.1 Requirements for the assembly of connections 7.1.1 Work on the installation of metal structures with tension-controlled bolted connections should be carried out in accordance with the working documentation, the approved work design, SP 70.13330 and section 7 of this standard.

7.1.2 Data on installation work should be entered daily into the log of work on making installation connections on bolts with controlled tension (Appendix A) in accordance with the requirements for the composition and procedure executive documentation, provided for by RD-11-02-2006 and RD-11-05-2007.

7.1.3 The designs used must comply with the requirements of the working documentation and section 6 of this standard, fasteners - standard

STO NOSTROY 2.10.76-2012

there or technical specifications specified in section 5 of this standard. Each batch of bolts, nuts and washers used must be provided with a quality certificate indicating the results of mechanical tests.

7.1.4 It is allowed to carry out incoming inspection of supplied fasteners according to appearance or mechanical properties. During incoming inspection, the compliance of the calculated value of the twist coefficient, geometric dimensions or mechanical properties of bolts, nuts and washers with the requirements of standards for fasteners is established. Mechanical properties are established, as a rule, by testing bolts for hardness and tensile strength and determining the actual tensile strength characteristics; nuts - for test load and hardness; washers - for hardness and flatness. The quality of the threads of bolts and nuts is controlled using thread gauges in accordance with GOST 24997.

7.1.5 Fasteners should be stored in a place protected from precipitation, sorted by strength classes, diameters and lengths, and high-strength bolts, nuts and washers - additionally by batch.

7.1.6 During larger assembly and installation metal constructions must be secured in order to ensure the stability and immutability of their position in space.

7.1.7 The execution of connections on bolts with controlled tension (friction, friction-shear and flange connections) and their delivery and acceptance should be carried out in accordance with SP 70.13330, under the guidance of the person appointed responsible for the implementation of this type of connection by order of the organization producing these work. Personnel who have been trained (in accordance with the requirements of SP 70.13330) and have a certificate of admission to the specified work and an order are allowed to perform connections. installation organization on the assignment of brands.

7.1.8 Technological process Performing bolted connections with tension controlled tension control provides for the following operations:

Preparation of bolts, nuts and washers (according to 7.2);

Preparation of contact surfaces (according to 7.3);

Assembling connections (according to 7.4);

Bolt tension (according to 7.5);

Monitoring the execution of connections (according to section 9);

Sealing of connections and priming of joints (according to 9.11);

Installation of the mark of the foreman and the person in charge (according to 7.5.13);

Entering the results of performing and monitoring connections in the “Log of performing installation connections on bolts with controlled tension” (Appendix A).

7.2 Preparation of bolts, nuts and washers

7.2.1 The technological process for preparing bolts, nuts and washers intended for connections with controlled bolt tension, supplied separately, in containers or boxes, includes operations for re-preservation, cleaning from dirt and rust, running the threads of rejected bolts and nuts and applying lubricant. The calculated value of the torque coefficient of bolts and nuts (without coating) is established in accordance with 7.5.6.

7.2.2 For bolts supplied complete with nuts and washers in sealed packaging that guarantees the preservation of a thin layer of factory preservative thread lubricant for the entire period of transportation and storage, re-preservation and lubrication of the threads of bolts and nuts is not required. The calculated value of the short-circuit twist coefficient can be taken in accordance with that recommended by the manufacturer after carrying out the incoming inspection (see 7.1.4 and Appendix B).

7.2.3 Re-preservation of bolts, nuts and washers should be done by boiling in water for 10 to 15 minutes. Lubrication of bolts and nuts is carried out after re-preservation (in a hot state) in a mixture of unleaded gasoline and mineral oil in accordance with GOST R 51634. The quantitative composition of the mixture is established depending on

STO NOSTROY 2.10.76-2012

viscosity of the mineral oil used.

The ratio of gasoline to oil (approximately 6:1 to 2:1) should provide a thin layer of lubricant on the surfaces of bolts and nuts throughout the entire storage period. The approximate consumption of gasoline per 100 kg of hardware is 2.2 liters, oil - 0.8 liters.

7.2.4 Prepared fasteners should be stored in closed boxes without access to precipitation for no more than 10 days.

Note – For more long-term storage the lubricant evaporates, friction in the thread increases, and the tension force of the bolts decreases.

If the storage period is exceeded, as well as after threading, fasteners must be re-lubricated.

7.2.5 To lubricate threads, it is allowed to use hard paraffin in accordance with GOST 23683. Cleaning bolts, nuts and washers from factory preservative lubricant in this case is carried out by boiling in water with the addition of detergent. Paraffin can be applied to the entire set (bolt, nut and two washers) or only to the nuts, preheated to a temperature of at least +80 °C. Paraffin consumption is from 3 to 4 g per 1 kg of fasteners. Detailed technology given in the recommendations.

7.2.6 For large volumes of work, a fastener preparation station equipped with lifting equipment is used (Figure 1).

7.2.7 To thread through rejected bolts and nuts, it is recommended to use appropriately equipped pneumatic or electric impact wrenches, as well as taps and dies of the required diameter.

7.2.8 Preparation of fasteners with metal coatings is permitted by lubricating the threads of the nuts by dipping them in a container with mineral oil according to GOST R 51634, no later than 8 hours before assembling the connections (about a day), followed by determining the value of the short-circuit twist coefficient using dynamometers control devices(Appendix B).

Installation of bolts without the use of lubricant, with a damaged coating, with traces of rust or with a Kz of 0.2 is not allowed.

7.3 Preparation of contact surfaces

7.3.1 Processing of contact surfaces on the installation site for friction, friction-shear, and flange connections on bolts with controlled tension is carried out in the manner specified in the CM in accordance with SP 16.13330.

7.3.2 Treated surfaces should be protected from dirt, oil and paint, as well as from the formation of ice. Dirt is removed with metal STO NOSTROY 2.10.76-2012 brushes, oil with solvents, paint and ice with heat.

7.3.3 If the period from the preparation of the contact surfaces to the assembly of the connection is more than 3 days, the contact surfaces should be re-processed using the method used during their initial processing.

7.3.4 Re-treatment does not apply to light rust deposits that form on contact surfaces after treatment or if they are exposed to atmospheric precipitation in the form of moisture or condensation of water vapor.

7.4 Assembling connections

7.4.1 The technological process for assembling connections includes:

Inspection of structures and verification of compliance of the geometric dimensions of assembled elements with the requirements of KM and KMD;

Aligning holes and fixing elements and connection parts in the design position using mounting mandrels;

Placing bolts in mandrel-free holes;

Tension of the supplied bolts to the force specified in the working documentation;

Removing the mandrels, placing the bolts in the vacated holes and tensioning them to the calculated force.

When assembling connections, it is not allowed:

Installation of bolts into holes formed by manual gas cutting or welding;

Use as assembly bolts of diameters and strength classes not specified in KM (KMD);

Re-tensioning of high-strength bolts to design strength.

7.4.2 The difference in thickness of the elements covered by the overlays, determined before installing the overlays using a ruler and feeler gauge, should not exceed 0.5 mm.

7.4.3 If the difference in thickness of the elements being connected is from 0.5 to 3.0 mm, for

STO NOSTROY 2.10.76-2012

To ensure smooth bending of the lining, the edge of the protruding element should be removed with an abrasive tool at a distance of at least 30 mm from the edge. If the difference is more than 3.0 mm, spacers should be used. The use of gaskets must be agreed with the project developer.

7.4.4 The discrepancy between the holes in individual parts of the assembled package (blackness) in accordance with SP 70.13330 should not exceed the difference in the nominal diameters of the holes and bolts and prevent the free installation of bolts into the holes without distortion.

7.4.5 In the assembled package, bolts of the diameter specified in the working documentation must pass through 100% of the holes. It is allowed to clean 20% of the holes with a drill or a conical rubber, the diameter of which is 1.0 mm greater than the nominal diameter of the bolt according to SP 70.13330.

7.4.6 In design connections, the use of bolts that do not have the manufacturer’s mark and markings indicating the strength class is not allowed.

7.4.7 Each bolt is installed in connection with two round washers (one is placed under the bolt head, the other under the nut). High-strength bolts with an increased wrench head size, with a difference in nominal diameters of holes and bolts of up to 4 mm, can be installed with one washer under the rotated element (nut or bolt head).

7.4.8 In shear connections, it is allowed to install two washers under the nut.

It is allowed not to install a washer under the bolt head.

7.4.9 When installing the bolts, the nuts must be freely screwed onto the threads, otherwise the nut or bolt should be replaced, and the rejected bolts and nuts should be sent for threading and re-preparation (see 7.2.7).

7.4.10 When exposed to connections installation loads the work of mounting mandrels and the work of bolts can be taken into account together.

7.4.11 The number of mandrels according to the condition of matching the holes should be 10% (but not less than 2 pieces), and the number of coupling bolts should be from 15% to 20% of the number of holes in the connection. The mandrels should be installed with light blows of a sledgehammer weighing no more than 2-3 kg, eliminating the formation of hardening around the holes in the planes of the contact surfaces.

7.4.12 Release of the mandrels is allowed after installation in all free holes of the bolts and tensioning them to a force of at least 30% of the design. The mandrels are released alternately with the installation of bolts replacing them.

7.4.13 Places and stages of installation of mandrels can be indicated in the work plan.

7.4.14 The lengths of the bolts of friction and flange connections are taken depending on the total thickness of the assembled package, taking into account the requirements that the thread protruding above the nut is at least one, and under the nut there are at least two threads with full profile. The lengths of bolts with a diameter from 12 to 48 mm, for a given package thickness, are given in Table 3.

7.4.15 The lengths of the bolts of friction-shear and shear connections are selected in such a way that the threads do not fall into the shear planes and are spaced from the nearest one at a distance of at least 5 mm or at least half the thickness of the element adjacent to the nut.

7.4.16 The tension of the bolts to the design force is carried out after alignment in space and checking the geometric dimensions of the assembled structures.

7.5 Bolt tension

7.5.1 The tension of the bolts to the design force is ensured by regulating the forces by monitoring the tightening torque with torque wrenches.

7.5.2 The tension of the bolts should be carried out from the middle of the connection or from its most rigid part towards the free edges. If the total thickness of the elements being connected exceeds 2 bolt diameters, the number of rounds must be at least two.

–  –  –

STO NOSTROY 2.10.76-2012 7.5.3 If, when tensioning the bolt, the nut is turned without increasing the torque reading on the torque wrench indicator, then the bolt and nut must be replaced.

7.5.4 The tension of the bolts is carried out, as a rule, by the nut. Pull on the bolt head is only permitted if the same type of lubricant is present on the bearing surfaces of the nuts and the bearing surfaces of the bolt heads. For example, when applying paraffin only to nuts, tensioning the bolts by the head is allowed after establishing the calculated value of Kz (according to Appendix B) when tensioning the bolts in a torque measuring device by the bolt head.

Nuts or bolt heads that are tightened to the design torque are marked with paint or chalk.

7.5.5 Adjustment of bolt tension forces is carried out in the following order:

The package is tightly tightened by tensioning 15% 20% of the supplied bolts (tie bolts) to 30% 100% of the calculated value of the torque M3, determined by formula (1), evenly distributing them over the connection field, with the location of the tie bolts in close proximity to the mandrels Necessarily;

All free holes are filled with bolts and tightened to 30% 100% of the calculated torque value M3;

The mandrels are replaced with bolts and all connection bolts are tightened to the design force;

Allowed to use mechanized methods tensioning bolts with electric or pneumatic impact wrenches of domestic or foreign production.

7.5.6 When regulating forces, the calculated value of the torque M3 for various diameters and strength classes of bolts, are determined by the formula M3 =P · db · K3 · Kn, (1) where P is the value of the axial tension force of the bolts specified in the project, N (kgf);

STO NOSTROY 2.10.76-2012 db nominal bolt diameter, m;

Kz coefficient of tightening of bolts and nuts, Kn = 1.05 – reliability coefficient.

Based on long-term statistical data, Kz is taken equal to 0.17 for bolts, nuts and washers supplied in accordance with GOST R 52643, GOST R 52644, GOST R 52645 and GOST R 52646, prepared in accordance with 7.2.3 and meeting the requirements of 7.2.4. The use of the KZ results specified in the certificates for individual batches of bolts and nuts is not allowed due to the lack of data on the preservative lubricant used and the condition of the threads of the bolts and nuts during factory acceptance tests.

7.5.7 The calculated value of the torque and the torque coefficient for bolts, nuts and washers with metal, paraffin or other types of coatings, as well as those supplied according to standards not specified in section 5, should be established experimentally, using torque control devices on certified equipment in in accordance with Appendix B and GOST R ISO 16047. The use of fasteners with damaged coating, as well as with Kz 0.2, is not allowed.

7.5.8 The values ​​of the axial tension forces of the bolts P, adopted in accordance with SP 16.13330 (clauses 6.7 and 14.3.6), as well as the tightening moments of bolts with a diameter of 16 to 30 mm, calculated according to formula (1), are given in Table 4.

7.5.9 Pre-tensioning of bolts up to 80% 90% of the design force is recommended to be done with impact wrenches, followed by tightening with torque wrenches. It is allowed to tighten the bolts with torque wrenches in one step when the number of bolts in the connection is no more than four and in hard-to-reach places.

7.5.10 The torque transmitted by the key must be recorded while the key is moving in the direction that increases the tension of the bolt.

Tightening should be done smoothly, without jerking.

STO NOSTROY 2.10.76-2012 7.5.14 The main technological operations when making bolted connections are given in Appendix E.

8 Making bolted connections without controlled tension

8.1 When making bolted connections without controlled tension, bolts, nuts and washers are installed in the joints without removing the factory preservative grease, and in its absence, the threads of the bolts and nuts are lubricated with mineral oil in accordance with GOST R 51634.

8.2 Before assembling the connections, the contact surfaces of elements and parts must be inspected and cleaned of burrs, dirt, loose rust, loose scale and ice. Cleaning is done with metal brushes, burrs are removed with electric or pneumatic grinders.

8.3 The connections are assembled in accordance with the requirements set out in 7.4. The discrepancy between the holes in individual parts of the assembled package (blackness) should not exceed the requirements of SP 70.13330.

The bolts are tightened to failure using mounting wrenches with a force from 294 N (30 kgf) to 343 N (35 kgf) length:

For M12 bolts – from 150 to 200 mm;

For M16 bolts – from 300 to 350 mm;

For M20 bolts – from 350 to 400 mm;

For M22 bolts – from 400 to 450 mm;

For M24 bolts – from 500 to 550 mm;

For M27 bolts - from 550 to 600 mm.

8.4 To prevent the nuts from unscrewing themselves, they are additionally secured by installing special washers or locknuts. For bolts operating in tension, the nuts should be secured exclusively by installing locknuts.

STO NOSTROY 2.10.76-2012 It is prohibited to weld nuts to the threads of bolts and to connection elements, as well as driving in threads protruding from the nut.

8.5 In structures that bear static loads, the nuts of bolts tightened to a force of 50% 70% of the minimum tensile strength of the bolt may not be further secured. In this case, it is necessary to fulfill the requirements specified in 7.4.15.

8.6 Nuts and bolt heads, including foundation bolts, after tensioning, must be in tight contact (without gaps) with the planes of the washers or structural elements, and the bolt shafts protrude from the nuts (lock nuts) by at least one full-profile thread turn. The tightness of the tie of the assembled package is subject to control with a 0.3 mm thick probe, which should not penetrate into the area limited by a radius of 1.3 do from the center of the bolt, where do is the nominal diameter of the hole.

8.7 Foundation (anchor) bolts must be tightened in accordance with the requirements of SP 43.13330 and KM (KMD) drawings. The results are documented in a document hidden work according to the form established in RD 11-02-2006.

8.8 In accordance with SP 70.13330, the tightening of bolts without controlled tension is checked by hitting them with a hammer weighing 0.4 kg, while the bolts should not move. Tensioning and checking the tightening of bolts can be done using torque wrenches.

9 Completion control, acceptance and sealing of bolted joints

9.1 The quality of bolted connections is checked through operational control. During operational control the following is checked:

Preparation of contact surfaces;

Bolt tension;

The density of the compressed package.

9.2 Control of the preparation of the contact surfaces of the connected elements STO NOSTROY 2.10.76-2012 and parts (linings, gaskets) is carried out by visual inspection immediately before assembling the joints. Defective surfaces or areas thereof must be corrected in accordance with the requirements of 7.3.

9.3 Bolt tension control is carried out in accordance with the requirements of 9.3.1 - 9.3.4.

9.3.1 The actual value of the axial tension force of the bolts is monitored using torque wrenches based on the torque value (see 7.5.1).

9.3.2 The number of bolts subject to control of axial force (tightening torque) must be:

If the number of bolts in a connection is up to 5, all bolts;

If the number of bolts in a connection is 6 or more - 15% of the number of bolts in the connection, but not less than 5 pieces.

9.3.3 During control, the actual value of the torque must be no less than that calculated using formula (1) and not exceed it by more than 10%.

9.3.4 If the tightening torque of at least one bolt does not correspond to the calculated value, double the number of bolts is checked. If in this case a loose bolt is detected, all bolts of this connection are checked.

The tension of all bolts must be brought to the design value.

9.4 The tightness of the package tie is controlled with a feeler gauge opposite the tightened bolt in accordance with the requirements set out in 6.27 and 8.6.

9.5 When inspecting bolted connections responsible person(see 7.1.7) first of all, an external inspection of all installed bolts is carried out. During the inspection it is necessary to check that:

All installed bolts are the same length;

Bolts and nuts are marked accordingly;

The washers are installed in accordance with the requirements of the working documentation;

The parts of the bolts protruding beyond the nut have at least one turn of thread STO NOSTROY 2.10.76-2012 with a full profile above the nut or at least two turns of thread under the nut (inside the package).

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The bolt is placed on straight lines - disks. The distance between the bolts in the direction of the force is called a pitch, perpendicularly - a track. The arrangement can be row or staggered.

The minimum distance between the bolts is taken from the possible position of their installation and the conditions for safe puncture. The maximum distance is taken subject to the density of the elements.

d - hole diameter t - thickness of the thinnest outer element

17.Calculation of bolted connections in elements subject to bending, longitudinal and transverse forces. Features of bolted connections in structures made of aluminum alloys.

Calculation of bolts in connections subject to axial force.

The required number of bolts is determined

n=, whereN bmin =minN bs

For connections with high-strength bolts

R bun – tensile strength of a high-strength bolt

μ = 0.57 – shot blasting, shot blasting.

μ = 0.5 - shot blasting, shot blasting with preservation by met. aluminum

μ = 0.42 – gas flame treatment

μ = 0.35 – steel brushes

μ = 0.25 – without treatment

γ b =0.8 –n<5

γ b =0.9 - 5n<10

γ h – connection reliability coefficient

γ h = 1.02…1.7 is taken depending on the method of surface treatment, the effective load (static, dynamic), the difference between the diameters of the hole and the bolt and the coefficient μ.

k- amount of friction surface

When calculating a rivet or bolt connection in case of complex tension the effect of bending moment, transverse and longitudinal forces is based on the assumption that longitudinal and transverse forces are equally distributed between all rivets and (bolts) of the half-joint, and the maximum force from the moment occurs in the rivets (bolts) furthest from the neutral axis. The calculation formula for determining the maximum force in the outer rivet (bolt) is:

where is the force attributable to the most loaded (outermost) horizontal row of rivets (bolts) of the half-joint:

The sum of squared distances between horizontal rows of rivets (bolts) equidistant from the neutral axis;

Number of vertical rows in a half-joint;

The total number of rivets (bolts) in a half-joint.

In the absence of longitudinal forces in the formula, and in the section of pure bending, in which and, the maximum force on the outer rivet (bolt), is taken. Knowing the voltage of the connections, it is checked using the formulas, assuming.

Calculation of bolts in bending joints.

When bending, the force in the bolts increases unevenly

The acting moment M is equal to

М= m ΣN i l i = m(N 1 l 1 +N 2 l 2 + …+N i l i)

l 1 =l max , N 1 =N max

N 3 =…=N max M=m(N max+ N max+…+ N max) = m (l 1 2 +l 2 2 +…+l i 2)= mΣl i 2

I APPROVED

Director___________________

___________ .___________________

1. GENERAL PROVISIONS

1.1. High-strength bolts, nuts and washers should be used in accordance with the instructions of the working (DM) or detailing (DM) drawings of the steel structures of the object being installed.

1.2. Work execution plans (WPP) must contain work execution diagrams or technological maps that provide for the execution of connections with high-strength bolts in the specific conditions of the facility being installed.

1.3. Preparation, assembly and acceptance of connections with high-strength bolts should be carried out under the supervision of a person (foreman, foreman) appointed by the order of the installation organization responsible for performing this type of connection at the site.

1.4. Installers who are at least 18 years old and have undergone special theoretical and practical training, confirmed by a personal certificate for the right to perform these works, issued by the installation organization, are allowed to make connections with high-strength bolts.

2. TECHNICAL REQUIREMENTS

2.1. Requirements for the materials used

2.1.1. High-strength bolts, nuts, washers must be supplied to the site being installed in batches provided with certificates in accordance with the requirements of GOST 22353-77, GOST 22354-77, GOST 22355-77, GOST 22356-77.

2.1.2. For sandblasting (shot blasting) treatment of contact surfaces of connected structural elements, quartz sand should be used in accordance with GOST 8736-77 or shot made of cast iron or steel in accordance with GOST 11964-81 E.

2.1.3. To form an adhesive friction coating on the contact surfaces of the linings, glue based on epoxy-dian resin ED-20 in accordance with GOST 10587-76 and carborundum powder of grades KZ and KCH, fractions No. 8, 10, 12 in accordance with GOST 3647-80 should be used.

2.1.4. For gas-flame treatment of surfaces, acetylene should be used in accordance with GOST 5457-75 and oxygen in accordance with GOST 6331-78. Acetylene and oxygen must be supplied to the work site in steel cylinders in accordance with GOST 15860-70.

2.2. Requirements for connected structural elements and tools

2.2.1. The possibility of free supply of high-strength bolts and screwing of nuts using impact wrenches and torque wrenches should be ensured by the design of the connections.

2.2.2. Installation of connections is not allowed if there are burrs on structural elements around and inside the holes, as well as along the edges of the elements.

The contact surfaces of the elements are not subject to priming or painting. The distance between the axis of the bolts of the last row and the primed surface should not be less than 70 mm.

2.2.3. It is not allowed to use elements in connections that have dimensional deviations that do not meet the requirements of SNiP III-18-75 “Rules for production and acceptance of work. Metal constructions". The difference between the planes of elements connected by overlays should not exceed 0.5 mm inclusive.

2.2.4. In connections made of rolled sections with non-parallel surfaces of shelves, leveling spacers must be used.

2.2.5. The nominal diameters and blackness of holes (mismatch of holes in individual parts of the assembled package) must not exceed the requirements specified in chapter SNiP III-18-75 “Rules for production and acceptance of work. Metal constructions".

2.2.6. Control and calibration torque wrenches must be numbered, calibrated and provided with calibration graphs or tables. Pneumatic and electric impact wrenches must meet the passport requirements.

3.1. Preparatory operations

3.1.1. Preparatory operations include: re-preservation and cleaning of high-strength bolts; preparation of structural elements; control and calibration check of the tool.

3.1.2. High-strength bolts, nuts, washers must be cleaned of factory preservation, dirt, rust and covered with a thin layer of lubricant. Depreservation and cleaning are carried out using the following technology.

3.1.3. Place high-strength bolts, nuts and washers weighing no more than 30 kg in lattice containers.

3.1.4. Immerse the lattice container filled with hardware in a tank of boiling water for 8 - 10 minutes (see drawing).

3.1.5. After boiling, rinse hot hardware in a mixture consisting of 85% unleaded gasoline according to GOST 2084-77 and 15% engine oil (type autol) according to GOST 20799-75 by immersing it 2-3 times, followed by drying.

3.1.6. Place processed bolts, nuts and washers separately in closed boxes with handles with a capacity of no more than 20 kg for transferring them to the workplace.

3.1.7. On the portable container, indicate the standard sizes, number of bolts, nuts and washers, processing date, certificate and batch numbers.

3.1.8. Cleaned bolts, nuts and washers should be stored in closed boxes for no more than 10 days, after which it is necessary to re-process in accordance with paragraphs. 3.1.4 and 3.1.5.

3.1.9. Burrs found around and inside holes, as well as along the edges of elements, must be completely removed. Removal of burrs around holes and along the edges of elements should be done using pneumatic or electric grinding machines without forming a recess that disrupts the contact of the contacting surfaces, and if there are burrs inside the hole, with a drill whose diameter is equal to the diameter of the bolt.

3.1.10. If the difference between the planes of the joined elements is more than 0.5 to 3.0 mm inclusive, it is necessary to make a bevel on the protruding element using a pneumatic or electric stripping machine at a distance of up to 30.0 mm from the edge of the element. If the difference between planes is more than 3.0 mm, leveling spacers should be used.

3.1.11. Calibration (checking calibration) of control and calibration torque wrenches should be done once per shift before starting work on special stands or devices in accordance with recommended Appendix 1. Calibration of impact wrenches is carried out in accordance with recommended Appendix 2.

Equipment for boiling high strength bolts, nuts and washers

1 - heating element; 2 — lattice container for bolts; 3 - water tank;

4 - drain plug

3.2. Basic technological operations

3.2.1. The main technological operations include:

— treatment of contact surfaces;

— assembly of connections;

— installation of high-strength bolts;

- tension and control of bolt tension.

3.2.2. The method of processing contact surfaces is selected in accordance with the friction coefficient specified in the KM or KMD drawings and chapter SNiP II-23-81 “Steel structures. Design standards".

The following methods for processing contact surfaces, carried out at the installation site, have been established: sandblasting (shot blasting); gas-flame; metal brushes; adhesive friction.

3.2.3. Sandblasting (shot blasting) of the contact surfaces of the joined elements should be carried out using sandblasting or shot blasting machines in accordance with GOST 11046-69 (ST SEV 3110-81).

When sandblasting (shot blasting) processing of contact surfaces, mill scale and rust must be completely removed until a uniform light gray surface is obtained.

3.2.4. Gas-flame treatment of contact surfaces must be carried out with wide-cut gas-flame burners GAO-60 or GAO-2-72 in accordance with GOST 17357-71.

Gas-flame processing is allowed with a metal thickness of at least 5.0 mm.

The burner movement speed is 1 m/min for metal thicknesses of more than 10 mm and 1.5-2 m/min for metal thicknesses up to 10 mm inclusive.

Combustion products and scale should be swept away with soft wire brushes and then with hair brushes.

The surface after flame treatment must be free from dirt, paint, oil stains and easily peelable scale. Complete removal of mill scale is not necessary.

The equipment of the gas-flame processing post and a brief technical characteristics of the equipment are given in the recommended Appendix 3.

3.2.5. Treatment of contact surfaces with metal brushes should be carried out using pneumatic or electric cleaning machines, the brands of which are indicated in the recommended Appendix 4.

It is not allowed to bring the contact surfaces to be cleaned to a metallic shine.

3.2.6. The adhesive friction coating on the contact surfaces of the linings is usually applied at manufacturing plants of metal structures.

The technological process for producing adhesive friction coating includes:

— processing of contact surfaces of linings in sandblasting (shot blasting) machines in accordance with GOST 11046-69 (ST SEV 3110-81);

— applying epoxy-polyamide glue to the treated contact surfaces of the pads;

- applying carborundum powder over uncured glue.

The safety of the adhesive friction coating must be ensured by packaging the linings for the entire period of their loading, transportation, unloading and storage at the construction site.

The shelf life of linings with adhesive friction coating is unlimited.

The composition of the adhesive friction coating is given in recommended Appendix 5.

Before assembly, the contact surfaces of the main connected elements must be treated with metal brushes in accordance with clause 3.2.5.

3.2.7. Metallization treatment of the contact surfaces of connected structural elements (galvanizing, aluminizing), as a rule, is carried out at manufacturing plants of metal structures.

3.2.8. Treated surfaces must be protected from dirt, oil, and ice formation. The shelf life of structures treated by sandblasting (shot blasting), gas flame methods or metal brushes before assembly should not exceed three days, after which the surfaces should be re-treated in accordance with paragraphs. 3.2.3 - 3.2.5.

Surfaces treated by sandblasting (shot blasting) can be cleaned using a gas flame method when re-processed.

3.2.9. Contact surfaces without treatment must be cleaned of dirt and loose scale with metal brushes; from oil - unleaded gasoline, from ice - by chipping.

3.2.10. Assembling connections with high-strength bolts includes the following operations:

— alignment of holes and fixation of connection elements in the design position using assembly plugs, the number of which should be 10% of the number of holes, but not less than 2 pcs.;

— installation of high-strength bolts in holes free from assembly plugs;

- tight seal of the package;

— tension of installed high-strength bolts to the force specified in the KM and KMD drawings;

— removing the assembly plugs, inserting high-strength bolts into the vacated holes and tensioning them to the design force;

— priming of the connection.

3.2.11. Under the heads and nuts of high-strength bolts it is necessary to place only one heat-treated washer in accordance with GOST 22355-77.

The protruding end of the bolt must have at least one thread above the nut.

3.2.12. If the holes do not coincide, their drilling in elements with machined surfaces should be done without using coolants.

3.2.13. Pre- and final tensioning of high-strength bolts must be carried out from the middle of the connection to the edges or from the most rigid part of the connection towards its free edges.

3.2.14. The method of tensioning high-strength bolts must be specified in the KM or KMD drawings.

3.2.15. In the absence of instructions, the tensioning method is selected by the installation organization according to the recommended Appendix 2.

4. ACCEPTANCE RULES AND CONTROL METHODS

4.1. After completing the assembly connection on high-strength bolts, the foreman is required to put a personal stamp (a set of numbers) on the connection and present the finished connection to the person in charge.

4.2. After inspection and verification, the responsible person (master, foreman) must present the finished connection to the customer’s representative. If the customer has no comments, the connection should be considered accepted and the person in charge enters all the necessary information about it into the journal for performing installation connections on high-strength bolts (see mandatory Appendix 6).

4.3. After acceptance, the finished connection should be primed and painted. The grades of primer and paint and varnish material are accepted according to the “List of polymeric materials and products approved for use in construction”, approved by the USSR Ministry of Health, the same as for priming and painting metal structures. The grades of primer and paint must be indicated in the KM and KMD drawings.

4.4. The responsible person checks the quality of connections made with high-strength bolts through operational control. Subject to control:

— quality of processing of contact surfaces;

— compliance of the installed bolts, nuts and washers with the requirements of GOST 22353-77, GOST 22354-77, GOST 22355-77, GOST 22356-77, as well as other requirements specified in the KM and KMD drawings;

— the presence of washers under the bolt heads and nuts;

— presence of manufacturer’s marks on the bolt heads;

— the length of the protruding part of the bolt thread above the nut;

— presence of the mark of the foreman in charge of the assembly of the compound.

4.5. The quality of processing of contact surfaces is checked by visual inspection immediately before assembling the connections. The control results must be recorded in a journal (see mandatory Appendix 6).

4.6. The compliance of the bolt tension with the design value is checked depending on the tension method. The deviation of the actual tightening torque from the torque specified in the KM and KMD drawings should not exceed 20%.

The angle of rotation of the nut is determined by the position of the marks on the protruding end of the bolt and nut. With two-stage bolt tensioning, the deviation of the rotation angle should be within ±15°, with single-stage tensioning - ±30°.

Bolts whose mark positions are outside the specified limits must be loosened and tightened again.

4.7. The tension of high-strength bolts is checked with a torque wrench or a calibrated control wrench.

The tension of the bolts should be controlled by spot check: with the number of bolts in a connection up to 5 inclusive, 100% of the bolts are controlled, with the number of bolts from 6 to 20 - at least 5, with a larger number - at least 25% of the bolts in the connection.

4.8. If the inspection reveals at least one bolt whose tension does not meet the requirements of clause 4.6 of this standard, then 100% of the bolts in the connection are subject to inspection. In this case, the tension of the bolts must be brought to the required value.

4.9. The density of the compressed bag is controlled with 0.3 mm probes. The probe should not pass between the planes along the contour of the elements being connected.

4.10. Documentation presented upon acceptance of the finished object, except for the documentation provided for by Chapter SNiP III-18-75 “Rules for production and acceptance of work. Metal structures" must contain:

— log of installation connections using high-strength bolts;

— certificates for bolts, nuts and washers;

— certificates for materials for the formation of adhesive friction coatings.

5. SAFETY REQUIREMENTS

5.1. The organization of the site for the enlarged assembly of structures with assembly connections on high-strength bolts should ensure the safety of workers at all stages of the work.

Work on the installation of structures on high-strength bolts must be carried out in accordance with the PPR, which contains the following safety solutions:

— organization of workplaces and passages;

— sequence of technological operations;

— methods and devices for safe work of installers;

— location and coverage areas of installation mechanisms;

— methods of storing building materials and structural elements.

5.2. The placement of work equipment and the organization of workplaces must ensure the safety of evacuation of workers in emergency situations, taking into account current building codes.

5.3. All work at height to make installation connections using high-strength bolts should be carried out from a scaffold that provides free access to the connection with the tool.

Scaffolding means and other devices that ensure the safety of work must comply with the requirements of Chapter SNiP III-4-80 “Rules for the production and acceptance of work. Safety in construction", GOST 12.2.012-75, GOST 24259-80 and GOST 24258-80.

5.4. Electrical safety at the installation site must be ensured in accordance with the requirements of GOST 12.1.013-78.

5.5. When processing contact surfaces with sandblasting (shot blasting) devices, the “Rules for the design and safety of operation of pressure vessels” approved by the USSR State Mining and Technical Supervision Authority should be followed.

5.6. The sandblasting (shot blasting) work area should be fenced and appropriate warning signs and notices should be posted near it.

5.7. Materials for sandblasting (shot blasting) surfaces (sand, shot, metal sand) should be stored in containers with a tightly closed lid.

5.8. The operator of the sandblasting (shot blasting) machine and the auxiliary worker are equipped with spacesuits or helmets with a forced supply of clean air.

5.9. The air supplied to the spacesuit must first be passed through a filter to remove dust, water and oil.

5.10. Between the workplaces of the operator and the auxiliary worker located near the sandblasting (shot blasting) machine, a sound or light alarm must be provided.

5.11. When treating contact surfaces with metal brushes (manual and mechanical), workers must be provided with safety glasses in accordance with GOST 12.4.003-80 or masks, mittens and respirators.

5.12. When processing contact surfaces using the gas-flame method, it is necessary to comply with the requirements of chapter SNiP III-4-80 “Rules for production and acceptance of work. Safety precautions in construction”, as well as sanitary rules for welding and cutting metals, approved by the USSR Ministry of Health.

5.13. Places where gas-flame work is carried out must be cleared of combustible materials within a radius of at least 5 m, and from explosive materials and installations (including gas cylinders and gas generators) - within a radius of 10 m.

5.14. It is not allowed to carry out work on gas-flame treatment of the surfaces of structural elements in rainy weather outside the premises without installing a canopy.

5.15. When performing gas-flame treatment of contact surfaces, workers must be provided with closed-type safety glasses with filter glasses of grades G-1 or G-2.

Auxiliary workers must be provided with safety glasses with filter glasses of grades B-1 or B-2.

5.16. The application of an adhesive friction layer to the surface of the linings, as a rule, should be carried out at manufacturing plants. In this case, the safety requirements in accordance with GOST 12.3.008-75, GOST 12.3.016-79 and GOST 10587-76 must be observed, as well as safety rules when working with synthetic adhesives.

5.17. The preparation of glue and the application of adhesive friction coatings must be carried out in a separate room equipped with exchange and local ventilation.

5.18. Persons working with epoxy-diane resins must be provided with protective clothing and gloves.

To protect the skin from the effects of epoxy-diane resins, protective pastes and ointments based on lanolin, petroleum jelly or castor oil should be used.

5.19. The room for applying adhesive friction coatings must be provided with fire extinguishing means - carbon dioxide and foam fire extinguishers.

5.20. Removal of bolts, nuts and washers should be carried out in an open area with a canopy.

5.21. When boiling hardware in water, the bath must be grounded. Workers re-preserving hardware should not have direct contact with boiling and lubricating baths. The loading process must be mechanized.

5.22. When performing assembly operations, alignment of holes and checking their coincidence in mounted structural elements must be done using a special tool - conical mandrels, assembly plugs, etc. It is not allowed to check the coincidence of holes with your fingers.

5.23. The operation of mechanisms and small-scale mechanization equipment, including maintenance, must be carried out in accordance with the requirements of chapter SNiP III-4-80 “Rules for production and acceptance of work. Safety precautions in construction" and instructions from manufacturers.

5.24. When using manual machines, you must comply with the safety rules provided for by GOST 12.1.012-79 (ST SEV 1932-79, ST SEV 2602-80) and GOST 12.2.010-75, as well as the instructions of the manufacturers.

5.25. The labor regime when working with manual electric and pneumatic machines and impact wrenches should be established in accordance with the “Recommendations for the development of Regulations on the labor regime of workers in vibration-hazardous professions,” approved in December 1971 by the All-Russian Central Council of Trade Unions, the USSR Ministry of Health, and the State Committee of the USSR Council of Ministers on Labor Issues and wages, as well as instructions from manufacturers for performing work with specific types of machines.

5.26. Priming and painting of finished connections on high-strength bolts should be done at the metal structures assembly site.

5.27. Only workers who know the rules for safe handling of the equipment and materials used and are familiar with fire safety rules are allowed to work on priming connections.

5.28. Workers engaged in priming and painting joints must undergo a medical examination in accordance with the requirements of Order No. 400 of the USSR Ministry of Health dated May 30, 1969 “On conducting preliminary upon employment and periodic medical examinations of workers.”

5.29. Temporary production and auxiliary premises must be provided with ventilation and lighting, and also equipped with fire extinguishing means in accordance with the requirements of GOST 12.4.009-75.

An example of calibration of a torque wrench type KTR-3 1

_________________

1 KTR-3 keys are manufactured by installation organizations according to the drawings of the Central Research Institute ProektStalkonstruktsiya.

Torque wrenches are calibrated on special calibration stands or by hanging a load of a given size to its handle. A torque wrench is hung on a hexagonal mandrel or a tightened high-strength bolt so that its handle is in a horizontal position (see drawing).

At a fixed point at the end of the key, a load weighing

Where M z— calculated torque;

D M z— moment equal to the product of the mass of the key and the distance from its center of gravity to the axis of the mandrel or bolt;

l— the distance from the center of gravity of the load to the axis of the mandrel or bolt.

When the load is suspended, the countdown is carried out using a recording device, for example, a dial indicator ICH 10 mm according to GOST 577-68. The measurement is carried out 2-3 times until a stable result is obtained. The calibration results are recorded in the wrench control calibration log (see mandatory appendix 7).

Torque wrench calibration diagram

1 - welded hexagon or tightened high-strength bolt;

2 - rigid support; 3 — indicator; 4 — calibrated wrench; 5 - calibrated load

Tensioning Methods for High Strength Bolts

1. Tension of high-strength bolts by tightening torque

1.1. High-strength bolts should be tensioned to the design force by tightening the nuts with a torque wrench to the design torque value. Torque value M z required to tension high-strength bolts is determined by the formula:

M z = kPd,

k— the average value of the torque coefficient for each batch of bolts according to the certificate or established using control instruments at the installation site;

R— bolt tension force specified in the KM and KMD drawings;

d- nominal diameter of the bolt.

1.2. To pre-tighten the nuts, pneumatic or electric impact wrenches specified in recommended Appendix 4 and torque wrenches should be used.

1.3. When tensioning the bolt, the head or nut should be held against turning with a mounting wrench. If turning does not stop as the bolt is tightened, the bolt and nut must be replaced.

1.4. The torque should be recorded as the key moves in the direction that increases tension.

Tightening should be done smoothly, without jerking.

1.5. Torque wrenches must be numbered and calibrated. They should be calibrated at the beginning of the shift.

2. Tension of high-strength bolts according to the angle of rotation of the nut

2.1. High-strength bolts must be installed in holes free of assembly plugs and tightened with a wrench adjusted to a tightening torque of 800 N × m. Each bolt must be tightened until the nut stops rotating. After removing the assembly plugs and replacing them with bolts, the latter must be tightened to a tightening torque of 800 N × m.

2.2. To control the angle of rotation of the nuts, it is necessary to apply marks on them and the protruding ends of the bolts using a combined center punch (see drawing) or paint.

Combined center punch

1 - center punch; 2 - nut; 3 - high-strength bolt; 4 - package

2.3. The final tightening is carried out with a wrench adjusted to a tightening torque of 1600 N × m, and the nut should turn to the angle indicated in the table.

3. Calibration of impact wrenches according to the angle of rotation of the nut

3.1. Calibration of impact wrenches should be carried out using a special calibration package consisting of three bodies with a number of holes of at least 20.

High-strength bolts are inserted into the holes of the calibration package and tightened with a wrench until the nut stops rotating. A group of bolts (calibration bolts) in an amount of at least 5 pcs. don't delay.

The calibration bolts must be manually tightened with a mounting wrench with a handle length of 0.3 m until failure (initial position).

3.2. The wrench is calibrated using the prepared calibration bolts.

3.3. The compressed air pressure is set so that when the nut is turned through an angle of 180±30° from its original position, the wrench fails.

Air pressure must be checked periodically.

Air pressure should be monitored using a GOST 2405-72 pressure gauge installed at the point where the impact wrench hose is connected to the line.

3.4. When calibrating the impact wrench (to monitor the angle of rotation of the nut), marks must be placed on its replaceable head.

3.5. The impact wrench is considered calibrated if the angle of rotation of the nut during the process of tensioning all bolts at the moment of failure of the impact wrench is 180 ± 30°.

3.6. The results of the impact wrench calibration must be entered into the impact wrench calibration log (see mandatory appendix 8).

3.7. If the compressed air pressure changes after eliminating a malfunction in the impact wrench, it is necessary to carry out a control calibration.

APPENDIX 3

Fire cleaning station equipment

APPENDIX 4

Equipment, mechanisms and tools used for processing contact surfaces, connecting elements and tensioning high-strength bolts

The vibration levels of electric and pneumatic hand-held grinding machines and impact wrenches (Table 1) do not exceed those established in GOST 16519-79 (ST SEV 716-77) and GOST 12.1.012-78.

Table 1

The noise levels of electric and pneumatic hand-held grinding machines and impact wrenches do not exceed those established in GOST 12.1.003-76. The vibration parameters and noise characteristics of electric and pneumatic manual machines used in processing the contact surfaces of connected elements and for tensioning high-strength bolts are given in Table 1, respectively. 2 and 3.

table 2

Vibration parameters

Table 3

Noise characteristics

Composition of adhesive friction coating

CONTACT ELECTRICAL CONNECTIONS CLASSIFICATION. GENERAL TECHNICAL REQUIREMENTS GOST 10434-82

STATE STANDARD OF THE USSR UNION
CONTACT ELECTRICAL CONNECTIONS
Classification. General technical requirements
Electric contact connections. Classification.
General technical requirements
GOST 10434-82

Recording date 01/01/83

This standard applies to dismountable and non-separable electrical contact connections of busbars, wires or cables (hereinafter referred to as conductors) made of copper, aluminum and its alloys, steel, aluminum-copper wires with terminals of electrical devices, as well as contact connections of conductors with each other for currents from 2. 5 A. For contact connections of electrical devices for currents less than 2.5 A, the standard requirements are recommended. The requirements of the standard regarding the permissible value of electrical resistance and durability of contact connections during through currents also apply to contact connections in circuits of grounding and protective conductors made of steel.

The standard does not apply to electrical contact connections of special-purpose electrical devices.

The terms used in the standard correspond to GOST 14312-79, GOST 18311-80.

1. CLASSIFICATION

1.1. Depending on the area of ​​application, electrical contact connections (hereinafter referred to as contact connections) are divided into classes in accordance with table. 1.

Table 1

Note. Standards and technical specifications for specific types of electrical devices must indicate classes 2 and 3; class 1 is not indicated.

1.2. Depending on the climatic version and the category of placement of electrical devices according to GOST 15150-69, contact connections are divided into groups in accordance with table. 2.

1.3. According to their design, contact connections are divided into non-separable and collapsible.

1.4. Depending on the material of the connected conductors and the group of contact connections according to clause 1.2, dismountable contact connections are divided into:

- not requiring the use of means for stabilizing electrical resistance - see paragraphs. 2.1.6 and 2.1.8;
- requiring the use of means of stabilizing electrical resistance - see paragraphs. 2.1.7 and 2.1.8.

table 2

2. TECHNICAL REQUIREMENTS

2.1. Design requirements

2.1.1. Contact connections must be made in accordance with the requirements of this standard, standards and technical specifications for specific types of electrical devices according to working drawings approved in the prescribed manner.

2.1.2. The terminals of electrical devices must comply with the requirements of GOST 24753-81.

2.1.3. Contact screw terminals must comply with the requirements of GOST 25034-85, type-set terminals must comply with the requirements of GOST 19132-86.

2.1.4. Linear fittings must comply with the requirements of GOST 13276-79.

2.1.5. Permanent contact connections must be made by welding, soldering or crimping. It is permissible to use other methods specified in the standards or technical specifications for specific types of electrical devices.

Examples of making permanent contact connections are given in Appendix 1.

2.1.6. Demountable contact connections that do not require the use of means for stabilizing electrical resistance must be made using steel fasteners protected from corrosion in accordance with the requirements of GOST 9.303-84, GOST 9.005-72.

2.1.7. Demountable contact connections requiring the use of means for stabilizing electrical resistance must be made using both individually and in combination the following means:

1) fasteners made of non-ferrous metals with a linear expansion coefficient from 18·10 -6 to 21·10 -6 1/°С;
2) disc springs in accordance with GOST 3057-90 or technical specifications for specific types of springs;
3) protective metal coatings of working surfaces, selected according to GOST 9.303-84, taking into account the requirements of GOST 9.005-72.
It is allowed to use other types of protective coatings specified in the standards or technical specifications for specific types of electrical devices;
4) transition parts in the form of copper-aluminum plates in accordance with GOST 19357-81, copper-aluminum tips in accordance with GOST 9581-80 and hardware clamps made of clad aluminum in accordance with TU 34-13-11438-89;
5) transition parts in the form of plates and tips made of aluminum alloy with a tensile strength of at least 130 MPa (hereinafter referred to as hard aluminum alloy);
6) pin tips according to GOST 23598-79 made of hard aluminum alloy;
7) pin tips according to GOST 23598-79, copper-aluminum;
8) electrically conductive lubricants or other electrically conductive materials, if the possibility of their use is confirmed by test results in accordance with GOST 17441-84 and is specified in the standards or technical specifications for specific types of electrical devices.

When using means 2)-8), contact connections, as a rule, must be made using steel fasteners protected from corrosion in accordance with the requirements of GOST 9.303-84, GOST 9.005-72.

Note. The need to apply a protective metal coating to the working surfaces of copper conductors must be specified in the standards or technical specifications for specific types of electrical devices.

(Changed edition, Amendment No. 1, 2, 3).

2.1.8. Demountable contact connections, depending on the group according to clause 1.2 and the material of the connected conductors and terminals of electrical devices, must be made in accordance with the requirements of the standard specified:

- for contact connections of conductors with flat leads, as well as contact connections of conductors among themselves - in table. 3;
- for contact connections of conductors with pin terminals - in table. 4;
- for contact connections of conductors with socket terminals - in table. 5.

Table 3

Contact connections in accordance with the climatic design and the category of placement of electrical devices, determined according to GOST 15150-69 and GOST 15543-70, must withstand the influence of environmental climatic factors specified in GOST 15150-69, GOST 15543-70, GOST 15963-79, GOST 16350-80, GOST 17412-72 or in standards and technical specifications for specific types of electrical devices.

Table 4

* Contact connections of electrical devices of climatic versions U, UHL of placement categories 1 and 2 may be manufactured according to clause 2.1.6.

Note. In all cases, copper or brass thrust nuts must be used for pin terminals rated above 40 A.

Table 5

* The possibility of direct connection must be specified in the standards or technical specifications for a specific type of electrical device.

** It is allowed to connect aluminum cores fused into a monolith with the addition of alloying additives from a hard aluminum alloy.

*** The contact connection is made by terminating with copper pin tips in accordance with GOST 22002.5-76, GOST 22002.12-76, GOST 22002.13-76, GOST 23598-79 or by tinning the cores with tin-lead solders in accordance with GOST 21931-76.

It is allowed, by agreement with the consumer, to use contact connections that differ from those indicated in the table. 3-5.

Examples of making collapsible contact connections are given in Appendix 2.

(Changed edition, Amendment No. 1, 3).

2.1.9. Contact connections of plates made of hard aluminum alloy and the aluminum part of copper-aluminum plates with aluminum conductors (leads) must be made by welding or soldering, and connections of lugs made of hard aluminum alloy and the aluminum part of copper-aluminum lugs with aluminum conductors of wires and cables must be made by welding or crimping.

2.1.10. Dismountable contact connections of single-wire conductors of wires and cables with flat or pin terminals must be carried out:

- cores with a cross-section of up to 16 mm 2 - after termination with lugs in accordance with GOST 7386-80 or directly: by forming into a ring or without it, with protection in both cases from extrusion with shaped washers or other methods;
- cores with a cross-section of 25 mm 2 or more - after termination with lugs in accordance with GOST 7386-80, GOST 7387-82, GOST 9581-80 or by forming the end of the core into a flat clamping part with a hole for a bolt.

2.1.11. Demountable contact connections of stranded wires and cables with flat or pin terminals must be carried out:

- cores with a cross-section of up to 10 mm 2 - after termination with lugs in accordance with GOST 7386-80, GOST 9688-82, GOST 22002.1-82, GOST 22002.2-76 - GOST 22002.4-76, GOST 22002.6-82, GOST 22002.7-76 - GOST 2200 2.11- 76, GOST 22002.14-76 or directly: by forming into a ring or without it, with protection in both cases from extrusion with shaped washers, or other methods;
- cores with a cross-section of 16 mm 2 or more - after termination with lugs in accordance with GOST 7386-80, GOST 7387-82, GOST 9581-80, GOST 22002.1-82, GOST 22002.2-76, GOST 22002.6-82, GOST 22002.7-76.

(Changed edition, Amendment No. 1, 2).

2.1.12. It is recommended to connect no more than two conductors to each flat terminal bolt (screw) or pin terminal, unless otherwise specified in the standards or technical specifications for specific types of electrical devices.

2.1.13. In collapsible contact connections, fasteners of strength classes in accordance with GOST 1759.4-87 and GOST 1759.5-87 specified in table should be used. 6. It is recommended to use screws in contact connections with a cylindrical or hexagonal head.

Table 6

2.1.14. Requirements for the preparation of working surfaces of contact parts are given in Appendix 3.

2.2. Electrical Requirements

2.2.1. The ratio of the initial electrical resistance of contact connections (except for contact connections with pin terminals) to the electrical resistance of the section of connected conductors, the length of which is equal to the length of the contact connection, should not exceed:

- for class 1 - 1, unless otherwise specified in the standards or technical specifications for specific types of electrical devices;
- for class 2 - 2;
- for grades 3 - 6.

In contact connections of conductors with different electrical resistance, a comparison is made with a contact part with greater electrical resistance.

2.2.2. The initial electrical resistance of contact connections of class 1 conductors with pin terminals should not exceed the values ​​​​specified in table. 7.

Table 7

Requirements for contact connections of classes 2 and 3, if necessary, are specified in standards or technical specifications for specific types of electrical devices.

2.2.3. The electrical resistance of contact connections (except welded and soldered), tested for compliance with the requirements of standards and other technical documentation according to the method specified in GOST 17441-84, should not exceed the initial value by more than 1.5 times. The electrical resistance of welded and soldered contact connections must remain unchanged. The need for mandatory use of torque indicator keys must be indicated in the standards or technical specifications for specific types of electrical devices.

2.2.4. When the rated (long-term permissible) current flows, the maximum permissible temperature of contact connections of classes 1 and 2 should not exceed the values ​​​​indicated in table. 8. In this case, the current loads of conductors are taken according to the “Rules for the Construction of Electrical Installations”, approved by Gosenergonadzor on April 12, 1969, according to standards or technical specifications for specific types of electrical devices.

Table 8

* It is allowed for conductors made of copper without insulation or with insulation of classes B, F and H according to GOST 8865-87 to increase the temperature to 135 ° C, if the possibility of this is confirmed by test results according to GOST 17441-84 and is indicated in the standards or technical specifications for specific types electrical devices.

The temperature of class 3 contact connections is established in standards or technical specifications for specific types of electrical devices, depending on the materials used, coatings, insulation class of connected conductors and operating conditions.

(Changed edition, Amendment No. 1, 2, 3).

2.2.5. (Deleted, Amendment No. 1).

2.2.6. After the through current mode, the contact connections should not have mechanical damage that would prevent their further operation. The temperature of contact connections in through current mode should not be more than 200 °C for connections of conductors made of aluminum copper, aluminum and its alloys, as well as for connections of these conductors with copper, 300 °C for connections of copper conductors and 400 °C for connections of steel conductors.

2.2.7. The value of the permissible through current of contact connections must be no less than the permissible through currents of specific types of electrical devices specified in the standards or technical specifications for these devices.

In the absence of these data, the value of the one-second current density should correspond to 165 A/mm 2 - for copper conductors, 105 A/mm 2 - for aluminum and aluminum-copper conductors, 90 A/mm 2 - for conductors made of aluminum alloy and 20 A/mm 2 - for steel conductors.

(Changed edition, Amendment No. 1).

2.3. Requirements for resistance to mechanical factors

2.3.1. Contact connections must withstand the effects of mechanical environmental factors according to the group of operating conditions in accordance with GOST 17516-72, which must be specified in the standards or technical specifications for specific types of electrical devices.

In the absence of such instructions, contact connections subject to vibration must withstand vibration for 1 hour at a constant frequency of 40 to 50 Hz and an amplitude of 1 mm.

2.3.2. Contact connections must withstand the effects of static axial tensile loads causing stresses of at least:

- 90% of the tensile strength of the entire conductor - for contact connections of power line wires operating in tension;
- 30% tensile strength of an entire conductor - for permanent contact connections that do not work in tension, as well as for connections of conductors with socket terminals, connections of unterminated wires and cables with flat terminals equipped with shaped washers.

For conductors with a cross section of up to 1.5 mm2, it is not allowed to use a screw clamp, the end of the screw of which is rotated along the core.

2.3.1.-2.3.3. (Changed edition, Amendment No. 1).

2.3.4. Dismountable contact connections of conductors with leads, single-bolt contact connections that may be exposed to through short-circuit currents, as well as dismountable contact connections subject to vibration or located in explosive areas must be protected from self-unscrewing by locknuts, spring washers, disc springs or other means.

(Changed edition, Amendment No. 2).

2.4. Reliability requirements

2.4.1. To assess the reliability of contact connections, a gamma-percentage resource is established, unless otherwise established in the standards or technical specifications for specific types of electrical devices.

The lower value of the gamma percentage resource must ensure the operation of electrical devices in accordance with the reliability requirements established in the standards or technical specifications for these electrical devices.

(Changed edition, Amendment No. 1).

2.5. Safety requirements

2.5.1. Contact connections in terms of safety requirements must comply with GOST 12.2.007.0-75 and ensure the operating conditions established by the “Rules for the technical operation of consumer installations” and “Safety rules for the operation of consumer electrical installations”, approved by Gosenergonadzor on April 12, 1969.

2.5.2. Contact connections in terms of fire safety requirements must comply with GOST 12.1.004-91, which is ensured by meeting the requirements of GOST 10434-82.

(Introduced additionally, Amendment No. 3).

ANNEX 1
Information

PERMANENT CONTACT CONNECTIONS

a - welding or soldering; b - with pin terminal welding; c - welding through a transition copper-aluminum plate; d - connection of wire (cable) cores through a connecting sleeve by crimping; d - connection of a wire (cable) core with a cable lug by crimping (welding, soldering); e - connection of wire cores in oval connectors

1 - flat output (bus); 2 - tire; 3 - pin terminal; 4 - copper-aluminum plate; 5 - wire (cable); 6 - connecting sleeve; 7 - cable lug; 8 - oval connector

APPENDIX 2
Information

DISMOUNTABLE CONTACT CONNECTIONS

a - with a lock nut; b - with a spring washer; c - single-wire (multi-wire) core of wire (cable) cross-section. up to 10 mm 2 with bending into a ring; g - single-wire (multi-wire) wire (cable) core cross-section. up to 10 mm 2 without bending into a ring.

1 - flat output (bus); 2 - bus (cable lug); 3, 4, 5 - steel washer, bolt and nut; 6 - spring washer; 7 - screw; 8 - shaped washer (star washer); 9 - wire (cable); 10 - shaped washer (arched washer)

a - fasteners made of non-ferrous metal with a lock nut; b - fasteners made of non-ferrous metal with a spring washer; c - steel fasteners with a disc spring; d - steel fasteners with protective metal coatings on working surfaces with a lock nut (spring washer); d - steel fasteners through a transition copper-aluminum plate with a lock nut (spring washer); e - steel fasteners through an adapter plate made of hard aluminum alloy with a lock nut (spring washer).

1 - flat output (bus); 2 - bus (cable lug); 3 - 5 - washer, bolt, nut made of non-ferrous metal; 6 - spring washer; 7 - steel nut; 8 - steel bolt; 9 - disc spring; 10 - steel washer (enlarged washer); 11 - steel washer; 12 - flat terminal (bus) with a protective metal coating of the working surface; 13 - busbar (cable lug) with a protective metal coating of the working surface; 14 - copper-aluminum plate; 15 - hard aluminum alloy plate

a - conductor made of copper, hard aluminum alloy or aluminum with a protective metal coating of the working surface; b, c, d - aluminum conductor; d - aluminum conductor through a copper-aluminum transition plate; e - single-wire (multi-wire) core of the cable cross-section. 10 mm 2 with bending into a ring.

1-pin copper or brass terminal; 2 - nut made of copper or brass; 3 - busbar (cable lug) made of copper, hard aluminum alloy or aluminum with a protective metal coating of working surfaces; 4 - steel nut; 5 - pin copper terminal; 6 - steel washer; 7 - aluminum busbar (cable lug); 8 - pin brass terminal; 9 - pin steel terminal; 10 - disc spring; 11 - copper-aluminum plate; 12 - wire (cable); 13 - spring washer; 14 - shaped washer (star washer)

a, b - single-wire (multi-wire, fused into a monolith) core; c - stranded core terminated with a cable lug.

1 - dial clamp; 2 - wire (cable); 3 - socket output; 4 - pin cable lug

REQUIREMENTS FOR PREPARATION OF WORKING SURFACES OF CONTACT PARTS

1. Contact parts that have two or more holes for bolts in a transverse row are recommended to be made with longitudinal cuts, as shown in the drawing.

2. The working surfaces of contact parts of dismountable contact connections and non-separable contact connections with linear fittings must be prepared immediately before assembly:

- copper without coating and aluminum-copper - stripped.
When stripping aluminum-copper wires, the copper sheath should not be damaged;
- aluminum and aluminum alloys - cleaned and lubricated with neutral lubricant (KVZ Vaseline in accordance with GOST 15975-70, CIATIM-221 in accordance with GOST 9433-80 or other lubricants with similar properties).
The recommended time between cleaning and lubrication is no more than 1 hour;
- working surfaces with protective metal coatings are washed with an organic solvent.

(Changed edition, Amendment No. 3).

3. The working surfaces of copper contact parts connected by crimping must be cleaned, unless otherwise specified in the standards or technical specifications for specific types of electrical devices.

The working surfaces of aluminum contact parts must be cleaned and lubricated with quartz-vaseline paste or other lubricants, pastes and compounds with similar properties.

4. The surfaces of contact parts connected by welding or soldering must first be cleaned, degreased or etched.

5. The location and size of holes for bolts in contact parts of dismountable contact connections is recommended to be taken in accordance with GOST 21242-75.

By agreement with the consumer, oval holes can be made.

(Introduced additionally, Amendment No. 2).

TORQUES

Table 9

Note. For bolted connections of conductors made of copper and hard aluminum alloy, it is recommended to use torques whose values ​​are 1.5 - 1.7 times higher than those specified in the table.

(Changed edition, Amendment No. 3).

INFORMATION DATA

1. DEVELOPED AND INTRODUCED by the Ministry of Installation and Special Construction Works of the USSR

DEVELOPERS
N. N. Dzektser, Ph.D. tech. Sciences (topic leader); V. L. Fuks; O. V. Fesenko, Ph.D. tech. sciences

2. APPROVED AND ENTERED INTO EFFECT by Resolution of the USSR State Committee for Product Quality Management and Standards dated 02/03/82 No. 450

3. INSTEAD GOST 10434-76

4. REFERENCED REGULATORY TECHNICAL DOCUMENTS

5. Validity period extended until 01/01/96 by Decree of the USSR State Committee for Product Quality Management and Standards dated 05/25/90 No. 1309

6. REISSUE (October 1993) with Amendments No. 1, 2, 3, approved in April 1985, June 1987, May 1990 (IUS 7-85, 10-87, 8-90)

Steel structures on a construction site are almost always connected using a bolted connection and it has many advantages over other connection methods and, above all, welded connections - ease of installation and quality control of the connection.

Among the disadvantages, one can note a higher metal consumption compared to a welded joint because In most cases, overlays are needed. In addition, the bolt hole weakens the section.

There are a great many types of bolted connections, but in this article we will consider the classic connection used in building structures.

SNiP II-23-81 Steel structures

SP 16.13330.2011 Steel structures (Updated edition of SNiP II-23-81)

SNiP 3.03.01-87 Load-bearing and enclosing structures

SP 70.13330.2011 Load-bearing and enclosing structures (Updated edition of SNiP 3.03.01-87)

STO 0031-2004 Bolted connections. Range and areas of application

STO 0041-2004 Bolted connections. Design and calculation

STO 0051-2006 Bolted connections. Manufacturing and installation

Types of bolted connections

By number of bolts: single-bolt and multi-bolt. I think there is no need to explain the meaning.

According to the nature of the transfer of force from one element to another:

Not shear-resistant and shear-resistant (friction). To understand the meaning of this classification, let’s consider how a bolted connection generally works when working in shear.

As you can see, the bolt compresses the 2 plates and part of the force is perceived by friction forces. If the bolts do not compress the plates strongly enough, then the plates slip and force Q is perceived by the bolt.

The calculation of non-shear-resistant connections implies that the tightening force of the bolts is not controlled and the entire load is transmitted only through the bolt without taking into account the friction forces that arise. This type of connection is called a connection without controlled bolt tension.

Shear-resistant or friction joints use high-strength bolts that tighten the plates with such force that the load Q is transferred through frictional forces between the 2 plates. Such a connection can be frictional or friction-shear; in the first case, only friction forces are taken into account in the calculation; in the second, friction forces and the shear strength of the bolt are taken into account. Although the friction-shear connection is more economical, it is very difficult to practically implement it in a multi-bolt connection - there is no certainty that all the bolts will simultaneously be able to bear the shear load, so it is better to calculate the friction connection without taking into account the shear.

For high shear loads, a friction connection is more preferable because The metal consumption of this compound is less.

Types of bolts by accuracy class and their application

Bolts of accuracy class A - these bolts are installed in holes drilled to the design diameter (i.e. the bolt fits into the hole without clearance). Initially, the holes are made of a smaller diameter and gradually drilled out to the desired diameter. The diameter of the hole in such connections should not be more than 0.3 mm larger than the diameter of the bolt. It is extremely difficult to make such a connection, so they are practically not used in building structures.

Bolts of accuracy class B (normal accuracy) and C (rough accuracy) are installed in holes 2-3 mm larger than the bolt diameters. The difference between these bolts is the bolt diameter error. For bolts of accuracy class B, the actual diameter can deviate by no more than 0.52 mm, for bolts of accuracy class C up to 1 mm (for bolts with a diameter of up to 30 mm).

For building structures, bolts of accuracy class B are usually used because in the realities of installation on a construction site, achieving high accuracy is almost impossible.

Types of bolts by strength and their application

For carbon steels, the strength class is indicated by two numbers separated by a dot.

There are the following bolt strength classes: 3.6; 3.8; 4.6; 4.8; 5.6; 5.8; 6.6; 8.8; 9.8; 10.9; 12.9.

The first number in the bolt strength classification indicates the tensile strength of the bolt - one unit indicates a tensile strength of 100 MPa, i.e. the tensile strength of a bolt of strength class 9.8 is 9x100=900 MPa (90 kg/mm²).

The second digit in the classification of the strength class indicates the ratio of the yield strength to the ultimate strength in tens of percent - for a bolt of strength class 9.8, the yield strength is equal to 80% of the ultimate strength, i.e. the yield strength is 900 x 0.8 = 720 MPa.

What do these numbers mean? Let's look at the following diagram:

Here is a general case of tensile testing of steel. The horizontal axis indicates the change in the length of the test sample, and the vertical axis indicates the applied force. As we can see from the diagram, with increasing force, the length of the bolt changes linearly only in the area from 0 to point A, the stress at this point is the yield strength, then with a slight increase in load the bolt stretches more strongly, at point D the bolt breaks - this is the strength limit . In building structures, it is necessary to ensure that the bolted connection operates within the yield strength.

The strength class of the bolt must be indicated on the end or side surface of the bolt head

If there are no markings on the bolts, then most likely these are bolts of a strength class below 4.6 (their markings are not required by GOST). The use of bolts and nuts without markings is prohibited in accordance with SNiP 3.03.01.

On high-strength bolts, the symbol of the melt is additionally indicated.

For the bolts used, it is necessary to use nuts corresponding to their strength class: for bolts 4.6, 4.8, nuts of strength class 4 are used, for bolts 5.6, 5.8, nuts of strength class 5, etc. You can replace nuts of one strength class with higher ones (for example, if it is more convenient to assemble nuts of the same strength class for an object).

When bolts are used only for shearing, it is allowed to use the strength class of the nuts with the bolt strength class: 4 – at 5.6 and 5.8; 5 – at 8.8; 8 – at 10.9; 10 – at 12.9.

For stainless steel bolts, markings are also applied to the bolt head. Steel class - A2 or A4 and tensile strength in kg/mm² - 50, 70, 80. For example A4-80: steel grade A4, strength 80 kg/mm² = 800 MPa.

The strength class of bolts in building structures should be determined according to Table D.3 SP 16.13330.2011

Selecting a bolt steel grade

The steel grade of bolts should be assigned according to Table D.4 SP 16.13330.2011

Selection of bolt diameter for constructiondesigns

For connections of building metal structures, bolts with a hexagonal head of normal accuracy in accordance with GOST 7798 or increased accuracy in accordance with GOST 7805 with a large thread pitch of diameters from 12 to 48 mm should be used, strength classes 5.6, 5.8, 8.8 and 10.9 in accordance with GOST 1759.4, hex nuts of normal accuracy in accordance with GOST 5915 or increased accuracy according to GOST 5927 strength classes 5, 8 and 10 according to GOST 1759.5, round washers for them according to GOST 11371 version 1 accuracy class A, as well as high-strength bolts, nuts and washers according to GOST 22353 - GOST 22356 diameters 16, 20 , 22, 24, 27, 30, 36, 42 and 48 mm.

The diameter and number of bolts are selected to ensure the required strength of the assembly.

If significant loads are not transmitted through the connection, then M12 bolts can be used. To connect loaded elements, it is recommended to use bolts from M16, for foundations from M20.

for M12 bolts - 40 mm;

for M16 bolts - 50 mm;

for M20 bolts - 60 mm;

for M24 bolts - 100 mm;

for M27 bolts - 140 mm.

Bolt hole diameter

For bolts of accuracy class A, the holes are made without clearance, but it is not recommended to use such a connection due to the great complexity of its manufacture. In building structures, as a rule, bolts of accuracy class B are used.

For bolts of accuracy class B, the hole diameter can be determined using the following table:

Bolt spacing

Distances when placing bolts should be taken according to table 40 SP 16.13330.2011

At joints and assemblies, the bolts must be placed closer to each other, and the structural connecting bolts (which serve to connect parts without transferring significant loads) at maximum distances.

It is allowed to fasten parts with one bolt.

Selecting Bolt Length

We determine the length of the bolt as follows: add up the thicknesses of the elements being connected, the thicknesses of the washers and nuts, and add 0.3d (30% of the bolt diameter) and then look at the range and select the nearest length (rounded up). According to building codes, the bolt must protrude from the nut by at least one turn. It will not be possible to use a bolt that is too long because... There is thread only at the end of the bolt.

For convenience, you can use the following table (from the Soviet reference book)

In bolted shear connections, with a thickness of the outer element up to 8 mm, the thread must be located outside the package of elements being connected; in other cases, the bolt thread should not go deeper into the hole by more than half the thickness of the outer element on the nut side or more than 5 mm. If the selected bolt length does not meet this requirement, then the bolt length must be increased so that this requirement is met.

Here's an example:

The bolt works for shear, the thickness of the fastened elements is 2x12 mm, according to the calculation, a bolt with a diameter of 20 mm, a washer thickness of 3 mm, a spring washer thickness of 5 mm, and a nut thickness of 16 mm are assumed.

The minimum bolt length is: 2x12+3+5+16+0.3x20=54 mm, according to GOST 7798-70 we select an M20x55 bolt. The length of the threaded part of the bolt is 46 mm, i.e. the condition is not satisfied because the thread should go no more than 5 mm into the hole, so we increase the length of the bolt to 2x12+46-5=65 mm. According to the standards, you can accept an M20x65 bolt, but it is better to use an M20x70 bolt, then all the threads will be outside the hole. The spring washer can be replaced with a regular one and another nut can be added (this is very often done because the use of spring washers is limited).

Measures to prevent loosening of bolts

To ensure that the fastening does not loosen over time, it is necessary to use a second nut or lock washers to prevent the bolts and nuts from unscrewing. If the bolt is in tension, then a second bolt must be used.

There are also special nuts with a locking ring or flange.

It is prohibited to use spring washers for oval holes.

Installing washers

No more than one washer should be installed under the nut. It is also allowed to install one washer under the bolt head.

Strength calculation of a bolted connection

Bolted connection can be divided into the following categories:

1) tensile connection;

2) shear connection;

3) connection working in shear and tension;

4) friction connection (working on shear, but with strong tension on the bolts)

Calculation of a bolted connection in tension

In the first case, the strength of the bolt is checked using formula 188 SP 16.13330.2011

where Nbt is the tensile load-bearing capacity of one bolt;

Rbt is the design tensile strength of the bolt;

Calculation of a bolted shear connection

If the connection works for shear, then it is necessary to check 2 conditions:

calculation for shear according to formula 186 SP 16.13330.2011

where Nbs is the shear load-bearing capacity of one bolt;

Rbs—design bolt shear resistance;

Ab is the gross cross-sectional area of ​​the bolt (accepted according to Table G.9 SP 16.13330.2011);

ns is the number of cuts of one bolt (if the bolt connects 2 plates, then the number of cuts is equal to one, if there are 3, then 2, etc.);

γb is the coefficient of operating conditions of a bolted connection, adopted in accordance with Table 41 SP 16.13330.2011 (but not more than 1.0);

γc is the operating condition coefficient adopted in accordance with Table 1 of SP 16.13330.2011.

and calculation for crushing according to formula 187 SP 16.13330.2011

where Nbp is the bearing capacity of one bolt in crushing;

Rbp is the design resistance of the bolt in crushing;

db is the outer diameter of the bolt shaft;

∑t - the smallest total thickness of the connected elements, crushed in one direction (if a bolt connects 2 plates, then the thickness of one thinnest plate is taken, if a bolt connects 3 plates, then the sum of thicknesses for plates that transmit the load in one direction and is compared with the thickness of the plate transmitting the load in the other direction and the smallest value is taken);

γb - coefficient of operating conditions of a bolted connection, accepted according to table 41 SP 16.13330.2011 (but not more than 1.0)

γc is the operating condition coefficient adopted in accordance with Table 1 of SP 16.13330.2011.

The design resistance of the bolts can be determined from table D.5 SP 16.13330.2011

The calculated resistance Rbp can be determined from table D.6 SP 16.13330.2011

The calculated cross-sectional areas of the bolts can be determined from table D.9 SP 16.13330.2011

Calculation of shear and tension joints

When forces are simultaneously applied to a bolted connection, causing shearing and tension of the bolts, the most stressed bolt, along with checking using formula (188), should be checked using formula 190 SP 16.13330.2011

where Ns, Nt are the forces acting on the bolt, shearing and tensile, respectively;

Nbs, Nbt - design forces determined by formulas 186 and 188 SP 16.13330.2011

Calculation of friction connection

Friction joints, in which forces are transmitted through friction that occurs along the contacting surfaces of the connected elements due to the tension of high-strength bolts, should be used: in structures made of steel with a yield strength of over 375 N/mm² and directly bearing moving, vibration and other dynamic loads; in multi-bolt connections, which are subject to increased requirements in terms of limiting deformability.

The design force that can be absorbed by each friction plane of elements fastened with one high-strength bolt should be determined using the formula 191 SP 16.13330.2011

where Rbh is the calculated tensile strength of a high-strength bolt, determined in accordance with the requirements of 6.7 SP 16.13330.2011;

Abn is the net cross-sectional area (adopted according to Table D.9 SP 16.13330.2011);

μ is the coefficient of friction between the surfaces of the parts being connected (accepted according to table 42 SP 16.13330.2011);

γh - coefficient adopted according to table 42 SP 16.13330.2011

The number of bolts required for a friction connection can be determined using the formula 192 SP 16.13330.2011

where n is the required number of bolts;

Qbh is the design force that one bolt absorbs (calculated using formula 191 SP 16.13330.2011, described just above);

k - the number of friction planes of connected elements (usually 2 elements are connected through 2 overhead plates located on different sides, in this case k = 2);

γc is the operating condition coefficient adopted in accordance with Table 1 of SP 16.13330.2011;

γb is the operating conditions coefficient, taken depending on the number of bolts required to absorb the force and taken equal to:

0.8 at n< 5;

0.9 at 5 ≤ n< 10;

1.0 for n ≤ 10.

Designation of bolted connections in drawings