The bolt is placed on straight lines - disks. The distance between the bolts in the direction of the force is called the step, perpendicularly - the track. The location can be ordinary and chess.

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 working on bending, longitudinal and transverse forces. Features of bolted connections in structures made of aluminum alloys.

Calculation of bolts in connections working on axial force.

The required number of bolts is determined

n=, where N bmin = minN bs

For connection 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 conservation by met. aluminum

μ = 0.42 – flame treatment

μ = 0.35 - steel brushes

μ = 0.25 - without treatment

γb =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 acting load (static, dynamic), the difference between the diameters of the hole and the bolt and the coefficient μ.

k is the amount of friction surface

When calculating a riveted or bolted connection in a complex stress state on the action of the bending moment, transverse and longitudinal forces, it is assumed that the longitudinal and transverse forces are equally distributed between all rivets and (bolts) of the semi-joint, and the maximum force from the action of the moment occurs in the rivets (bolts) furthest from the neutral axis. The calculation formula for determining the maximum force in the extreme rivet (bolt) is:

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

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

The number of vertical rows in the half joint;

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

In the absence of longitudinal forces in the formula, they take , and in the section of a pure bend, in which and, the maximum force on the extreme rivet (bolt),. Knowing the voltage of the connections is checked by the formulas, assuming.

Calculation of bolts in bending connections.

When bending, the force in the bolts increases unevenly

The current moment M is equal to

M \u003d m ΣN i l i \u003d m (N 1 l 1 + N 2 l 2 + ... + N i l i)

l 1 \u003d l max, N 1 \u003d 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

Bolted connections and connections on high-strength bolts

12.14. Holes in the details of steel structures should be made in accordance with the requirements of SNiP according to the rules for the production and acceptance of work for metal structures.

12.15*. Accuracy class A bolts should be used for connections in which holes are drilled to the design diameter in assembled elements or along conductors in individual elements and parts, drilled or driven to a smaller diameter in separate parts, followed by reaming to the design diameter in assembled elements.

Bolts of accuracy class B and C in multi-bolt connections should be used for structures made of steel with a yield strength of up to 380 MPa (3900 kgf / cm 2).

12.16. Elements in the node can be fixed with one bolt.

12.17. Bolts having sections with different diameters along the length of the uncut part are not allowed to be used in joints in which these bolts work in shear.

12.18*. Round washers should be installed under bolt nuts in accordance with GOST 11371-78*, washers should be installed under nuts and heads of high-strength bolts in accordance with GOST 22355-77*. For high-strength bolts in accordance with GOST 22353-77 * with increased sizes of heads and nuts and with a difference in the nominal diameters of the hole and bolt not exceeding 3 mm, and in structures made of steel with a tensile strength of at least 440 MPa (4500 kgf / cm 2) not exceeding 4 mm, it is allowed to install one washer under the nut.

The thread of the shear bolt should not be more than half the thickness of the element adjacent to the nut, or more than 5 mm, except for structural structures, power transmission towers and open switchgear and transport contact lines, where the thread must be outside the package of connected elements.

12.19*. Bolts (including high-strength ones) should be placed in accordance with Table. 39.

Connecting bolts should be placed, as a rule, at maximum distances, at joints and nodes, bolts should be placed at minimum distances.

When placing bolts in a checkerboard pattern, the distance between their centers along the force should be taken at least a + 1,5d, where a- distance between rows across the force, d- Bolt hole diameter. With this placement, the section of the element A n is determined taking into account its weakening by holes located only in one section across the force (not along the "zigzag").

When attaching a corner with one shelf, the hole farthest from its end should be placed at the risk closest to the butt.

12.20*. In connections with bolts of accuracy classes A, B and C (with the exception of fastening secondary structures and connections on high-strength bolts), measures must be taken against unscrewing the nuts (setting spring washers or lock nuts).

Table 39

Distance characteristic	Bolt spacing
1. Distances between bolt centers in any direction:
a) minimum
b) the maximum in the extreme rows in the absence of bordering corners in tension and compression	8d or 12 t
c) the maximum in the middle rows, as well as in the outer rows in the presence of bordering corners:
in tension	16d or 24 t
under compression	12d or 18 t
2. Distances from the center of the bolt to the edge of the element:
a) minimum along effort
b) the same, across the effort:
with cut edges
with rolling edges
c) maximum	4d or 8 t
d) minimum for high-strength bolts with any edge and any direction of force
* In connected elements made of steel with a yield strength of more than 380 MPa (3900 kgf / cm 2), the minimum distance between the bolts should be taken equal to 3 d. Designations adopted in table 39: d- bolt hole diameter; t is the thickness of the thinnest outer element. Note. In connected elements made of steel with a yield strength of up to 380 MPa (3900 kgf / cm 2), it is allowed to reduce the distance from the center of the bolt to the edge of the element along the force and the minimum distance between the centers of the bolts in cases of calculation taking into account the relevant coefficients of the operating conditions of the joints in accordance with paragraphs. 11.7* and 15.14*.

13. Additional requirements for the design of industrial buildings and structures 1

Relative deflections and deviations of structures

13.1*. Deflections and displacements of structural elements should not exceed the limit values ​​established by SNiP for loads and impacts.

Tab. 40* is excluded.

13.2-13.4 and Table 41* are excluded.

1 It is allowed to apply to other types of buildings and structures.

Distances between expansion joints

13.5. The greatest distances between the expansion joints of steel frames of one-story buildings and structures should be taken according to Table. 42.

When exceeding more than 5% of those indicated in Table. 42 distances, as well as with an increase in the rigidity of the frame by walls or other structures, the calculation should take into account climatic temperature effects, inelastic deformations of structures and compliance of nodes.

Table 42

Characteristics of buildings and structures	The greatest distances, m
	between expansion joints				from the expansion joint or the end of the building to the axis of the nearest vertical connection
	along the length of the block (along the building)		by block width
	in climatic areas of construction
		I 1 , I 2 , II 2 and II 3	all except I 1 , I 2 , II 2 and II 3	I 1 , I 2 , II 2 and II 3	all except I 1 , I 2 , II 2 and II 3	I 1 , I 2 , II 2 and II 3
Heated buildings
Unheated buildings and hot shops
Open flyovers
Note. If there are two vertical connections between the expansion joints of a building or structure, the distance between the latter in the axes should not exceed: for buildings - 40-50 m and for open flyovers - 25-30 m, while for buildings and structures erected in climatic regions I 1 , I 2 , II 2 and II 3 , the smaller of the indicated distances should be taken.

Farms and structural

coating slabs

13.6. The axes of the bars of trusses and structures should, as a rule, be centered at all nodes. The centering of the rods should be carried out in welded trusses according to the centers of gravity of the sections (rounded up to 5 mm), and in bolted trusses - according to the risks of the corners closest to the butt.

The displacement of the axes of the truss chords when changing the sections may not be taken into account if it does not exceed 1.5% of the height of the chord.

In the presence of eccentricities at the nodes, the elements of trusses and structures should be calculated taking into account the corresponding bending moments.

When loads are applied outside the truss nodes, the chords must be designed for the combined action of longitudinal forces and bending moments.

13.7. When spanning roof trusses over 36 m, a construction lift equal to the deflection from constant and long-term loads should be provided. For flat roofs, construction lifting should be provided regardless of the span, taking it equal to the deflection from the total standard load plus 1/200 of the span.

13.8. When calculating trusses with elements from corners or tees, the connections of elements in the truss nodes can be taken as hinged. With I-beam, H-shaped and tubular sections of elements, the calculation of trusses according to the hinged scheme is allowed when the ratio of the height of the section to the length of the elements does not exceed: 1/10 - for structures operated in all climatic regions, except for I 1, I 2, II 2 and II 3 ; 1/15 - in areas I 1 , I 2 , II 2 and II 3 .

If these ratios are exceeded, additional bending moments in the elements due to the rigidity of the nodes should be taken into account. It is allowed to take into account the stiffness of nodes in trusses by approximate methods; axial forces are allowed to be determined according to the hinged scheme.

13.9*. The distance between the edges of the elements of the lattice and the belt in the nodes of welded trusses with gussets should be taken at least a = 6t- 20 mm, but not more than 80 mm (here t- gusset thickness, mm).

A gap of at least 50 mm should be left between the ends of the joined elements of the truss belts, overlapped by overlays.

The welds that attach the elements of the truss lattice to the gussets should be brought to the end of the element to a length of 20 mm.

13.10. In truss nodes with belts made of T-beams, I-beams and single corners, fastening of gussets to the shelves of the belts end-to-end should be carried out with penetration through the entire thickness of the gusset. In designs of group 1, as well as those operated in climatic regions I 1, I 2, II 2 and II 3, the junction of nodal gussets to the belts should be performed in accordance with pos. 7 table 83*.

columns

13.11. The sending elements of through columns with gratings in two planes should be reinforced with diaphragms located at the ends of the sending element.

In through columns with a connecting grid in the same plane, the diaphragms should be located at least 4 m apart.

13.12*. In centrally compressed columns and racks with one-sided girdle seams in accordance with clause 12.9 * in the attachment points of braces, beams, struts and other elements in the force transfer zone, two-sided girdle seams should be used that extend beyond the contours of the attached element (node) by a length of 30 kf from each side.

13.13. Fillet welds attaching the gussets of the connecting grid to the overlapping columns should be assigned according to the calculation and placed on both sides of the gusset along the column in the form of separate sections in a checkerboard pattern, while the distance between the ends of such seams should not exceed 15 gusset thicknesses.

In structures erected in climatic regions I 1, I 2, II 2 and II 3, as well as when using manual arc welding, the seams must be continuous along the entire length of the gusset.

13.14. Assembly joints of columns should be made with milled ends, butt-welded, on overlays with welded seams or bolts, including high-strength ones. When welding overlays, the seams should not be brought to the joint by 30 mm on each side. It is allowed to use flange connections with the transfer of compressive forces through a tight touch, and tensile ones - by bolts.

Connections

13.15. In each temperature block of the building, an independent system of connections should be provided.

13.16. The lower chords of crane beams and trusses with a span of more than 12 m should be reinforced with horizontal braces.

13.17. Vertical connections between the main columns below the level of crane beams with two-branch columns should be located in the plane of each of the branches of the column.

The branches of two-branch connections, as a rule, should be interconnected by connecting grids.

13.18. Transverse horizontal connections should be provided at the level of the upper or lower chords of roof trusses in each span of the building along the ends of the temperature blocks. If the length of the temperature block is more than 144 m, intermediate transverse horizontal braces should be provided.

Rafter trusses that are not directly adjacent to the cross braces should be braced in the plane of the location of these braces with spacers and stretch marks.

At the locations of the cross-links, vertical links between the trusses should be provided.

In the presence of a hard disk of the roof at the level of the upper chords, removable inventory ties should be provided to align the structures and ensure their stability during installation.

In the coatings of buildings and structures operated in climatic regions I 1, I 2, II 2 and II 3, as a rule, vertical ties should be provided (in addition to those usually used) in the middle of each span along the entire building.

13.19*. Longitudinal horizontal connections in the plane of the lower chords of roof trusses should be provided along the outermost rows of columns in buildings with cranes of operating mode groups 6K-8K according to GOST 25546-82; in coverings with truss trusses; in one- and two-span buildings with overhead cranes with a lifting capacity of 10 tons or more, and with a mark of the bottom of the truss structures over 18 m - regardless of the lifting capacity of the cranes.

In buildings with more than three spans, horizontal longitudinal ties should also be placed along the middle rows of columns at least every span in buildings with cranes of operating mode groups 6K-8K according to GOST 25546-82 and two spans in other buildings.

13.20. Horizontal connections along the upper and lower chords of the split trusses of spans of conveyor galleries should be designed separately for each span.

13.21. When using a cross lattice of coating ties, it is allowed to calculate according to a conditional scheme on the assumption that the braces perceive only tensile forces.

When determining the forces in the elements of the connections, the compression of the truss chords, as a rule, should not be taken into account.

13.22. When installing a membrane deck in the plane of the lower chords of trusses, it is allowed to take into account the operation of the membrane.

13.23. In hanging pavements with planar bearing systems (double-zone, flexural-rigid guys, etc.), vertical and horizontal connections between the bearing systems should be provided.

beams

13.24. The use of sheet packs for chords of welded I-beams is generally not allowed.

For beam chords on high-strength bolts, it is allowed to use packages consisting of no more than three sheets, while the area of ​​the waist corners should be taken equal to at least 30% of the entire area of ​​the chord.

13.25. Belt seams of welded beams, as well as seams that attach auxiliary elements to the main beam section (for example, stiffeners), must be continuous.

13.26. When using one-sided belt welds in welded I-beams bearing a static load, the following requirements must be met:

design load must be applied symmetrically with respect to the cross section of the beam;

the stability of the compressed beam chord must be ensured in accordance with clause 5.16*, a;

in places where concentrated loads are applied to the beam chord, including loads from ribbed reinforced concrete slabs, transverse stiffeners should be installed.

In the crossbars of frame structures at the support nodes, two-sided waist seams should be used.

In beams calculated in accordance with the requirements of paragraphs. 5.18 * -5.23 of these standards, the use of one-sided waist seams is not allowed.

13.27. The stiffeners of welded beams must be removed from the wall joints at a distance of at least 10 wall thicknesses. At the intersection of the butt welds of the beam web with a longitudinal stiffener, the seams attaching the rib to the web should not be extended to the butt weld by 40 mm.

13.28. In welded I-beams of structures of groups 2-4, as a rule, one-sided stiffeners should be used with their location on one side of the beam.

In beams with one-sided waist welds, stiffeners should be located on the side of the web opposite to the location of one-sided waist welds.

Crane beams

13.29. The strength analysis of crane beams should be performed in accordance with the requirements of clause 5.17 for the effect of vertical and horizontal loads.

13.30*. The calculation of the strength of the walls of crane beams (with the exception of beams calculated for endurance, for cranes of the operating mode groups 7K in the shops of metallurgical production and 8K according to GOST 25546-82) should be performed according to formula (33), in which, when calculating the sections on the supports of continuous beams instead of a coefficient of 1.15, a coefficient of 1.3 should be taken.

13.31. Calculation for the stability of crane beams should be carried out in accordance with clause 5.15.

13.32. Checking the stability of the walls and belt sheets of crane beams should be carried out in accordance with the requirements of Sec. 7 of these rules.

13.33*. Crane beams should be calculated for endurance in accordance with Sec. 9 of these standards, while taking into account a= 0.77 for cranes of operating mode groups 7K (in metallurgical production shops) and 8K according to GOST 25546-82 and a= 1.1 in other cases.

In crane beams for cranes of operating mode groups 7K (in metallurgical production shops) and 8K according to GOST 25546-82, the walls should additionally be calculated for strength in accordance with clause 13.34* and endurance in accordance with clause 13.35*.

Calculation of crane beams for strength and endurance should be carried out for the action of crane loads, installed in accordance with the requirements of SNiP for loads and impacts.

13.34*. In the compressed zone of the walls of crane beams made of steel with a yield strength of up to 400 MPa (4100 kgf / cm 2), the following conditions must be met:

g f 1 - the coefficient of increase in the vertical concentrated load on an individual crane wheel, taken in accordance with the requirements of SNiP for loads and impacts;

F- design pressure of the crane wheel without taking into account the dynamic factor;

lef- conditional length, determined by the formula

where with- coefficient accepted for welded and rolled beams 3.25, for beams on high-strength bolts - 4.5;

J 1f- the sum of the own moments of inertia of the chord of the beam and the crane rail or the total moment of inertia of the rail and the chord in the case of welding the rail with seams that ensure the joint operation of the rail and the chord;

M t- local torque, determined by the formula

M t = Fe + 0,75 Q t h r, (147)

where e- conditional eccentricity, taken equal to 15 mm;

Q t- transverse calculated horizontal load caused by distortions of the overhead crane and non-parallelism of crane tracks, taken in accordance with the requirements of SNiP for loads and impacts;

hr- crane rail height;

where Rn- design fatigue resistance for all steels, taken equal, respectively, for welded beams and high-strength bolts: Rn\u003d 75 MPa (765 kgf / cm 2) and 95 MPa (930 kgf / cm 2) for the compressed upper zone of the wall (section in the span of the beam); Rn\u003d 65 MPa (665 kgf / cm 2) and 89 MPa (875 kgf / cm 2) for the tensioned upper zone of the wall (supporting sections of continuous beams).

The stress values ​​in formula (148) should be determined according to clause 13.34 * from crane loads, established in accordance with the requirements of SNiP for loads and effects.

Upper girdle seams in crane girders for cranes of operating mode groups 7K (in metallurgical production shops) and 8K according to GOST 25546-82 must be made with penetration through the entire wall thickness.

13.36. The free edges of the stretched chords of crane beams and beams of working platforms that directly perceive the load from rolling stock must be rolled, planed or cut by machine oxygen or plasma-arc cutting.

13.37*. The dimensions of the stiffeners of the crane beams must meet the requirements of clause 7.10, while the width of the protruding part of the double-sided rib must be at least 90 mm. Bilateral transverse stiffeners must not be welded to beam chords. The ends of the stiffeners must be tightly fitted to the upper chord of the beam; at the same time, in beams for cranes of operating modes groups 7K (in metallurgical production shops) and 8K according to GOST 25546-82, it is necessary to plan the ends adjacent to the upper chord.

In beams for cranes of operating mode groups 1K-5K according to GOST 25546-82, it is allowed to use one-sided transverse stiffeners with their welding to the wall and to the upper chord and location in accordance with clause 13.28.

13.38. The strength calculation of suspension beams of crane rails (monorails) should be performed taking into account local normal stresses at the site of application of pressure from the crane wheel, directed along and across the axis of the beam.

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Documents on standardization
Metal structures

CJSC "TsNIIPSK im. Melnikov

OAO NIPI Promstalkonstruktsiya

organization standard

BUILDING STEEL STRUCTURES
BOLT CONNECTIONS
Manufacturing and installation

STO 0051-2006
(02494680, 01408401)

Moscow
2006

Foreword

1 DEVELOPED CJSC Central Order of the Red Banner of Labor Research and Design Institute of Building Metal Structures. N.P. Melnikov (CJSC TsNIIPSK named after Melnikov).

OJSC Research and Design Institute "Promstalkonstruktsiya"

2 INTRODUCED by standards development organizations

3 ADOPTED at the Scientific and Technical Council TsNIIPSK them. Melnikov dated January 26, 2006 with the participation of representatives of the organization that developed the standard

4 INTRODUCED for the first time

5 Development, approval, approval, publication (replication), updating (change or revision) and cancellation of this standard are carried out by developing organizations

Introduction

This standard was developed in accordance with the Federal Law "On Technical Regulation" No. 184-FZ and is intended for use by all divisions of ZAO TsNIIPSK im. Melnikov" and JSC NIPI "Promstalkonstruktsiya", specializing in the development of projects of KM and KMD, diagnostics, repair and reconstruction of industrial buildings and structures for various purposes.

The standard can be applied by other organizations if these organizations have certificates of conformity issued by the Certification Bodies in the voluntary certification system created by the standard development organizations.

Organizations-developers do not bear any responsibility for the use of this standard by organizations that do not have certificates of conformity.

The need to develop a standard is dictated by the fact that the experience gained by the organizations developing the standard, as well as domestic enterprises and organizations in the field of design, manufacture and implementation of steel structures with bolted field connections, is contained in various regulatory documents, recommendations, departmental rules and others, in part obsolete and not generally covering the problem of safe operation of industrial buildings and structures for various purposes.

The main purpose of developing the standard is to create a modern regulatory framework for the manufacture and installation of steel structures with bolted connections.

Please send comments and suggestions on additions and changes to this standard to the following addresses:

117393 Moscow, st. Architect Vlasov, 49, ZAO TsNIIPSK im. Melnikov, fax 960-22-77, phone numbers for inquiries: 128-77-77, 120-10-21;

127473 Moscow, st. Sadovaya Samotechnaya, 13, OJSC NIPI Promstalkonstruktsiya, phone numbers (fax) for inquiries 200-17-02, 684-32-65.

Approved and put into effect:

Introduction date - 2006-03-01

1 area of ​​use

This standard applies to the manufacture and installation of load-bearing and enclosing steel building structures with bolted mounting joints, including high-strength ones, designed for stationary, collapsible and mobile buildings and structures for various purposes, perceiving permanent, temporary and special loads such as mobile, vibration , explosive, seismic in climatic regions with an estimated temperature of up to -65 ° C and seismicity up to 9 points, operated both in slightly aggressive and in medium aggressive and aggressive environments with the use of protective metal and paint coatings.

2 Normative references

Federal Law "On Technical Regulation" dated December 27, 2002 No. 184-FZ

3.2 The standard applies to the manufacture and installation of structures with bolted connections of the following types:

Friction, in which shear forces are perceived by friction forces acting on the contact surfaces of the elements to be connected as a result of the tension of the bolts for the design force;

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

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

Flanged, in which pre-tightened bolts work in tension with rigid flanges or in tension with bending with flexible flanges;

Bolt-riveting, used in the repair of riveted structures, in which the decrease in bearing capacity is compensated by friction forces after replacing defective rivets with bolts tightened to the design force.

3.3 Steel structures must be manufactured and assembled in accordance with the working documentation of KM (metal structures) and KMD (metal detailing structures). Design and calculation of bolted connections must be carried out in accordance with the requirements of STO 0041-2004.

3.4 The KM drawings must indicate:

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;

Bolt tensioning method - according to the torque;

Method of preparation of contact surfaces with indication of the calculated value of the coefficient of friction;

Parts and areas that are not subject to priming or painting at the steel structure manufacturer;

Additional requirements for the manufacture and installation of metal structures;

Normative documents on the manufacture of structures and technology for making bolted connections.

3.5 When developing KMD drawings, the technological capabilities of the manufacturer and the specifics of the installation work should be taken into account.

3.6 The organization that developed the KMD drawings is responsible for their compliance with the design decisions adopted in the KM drawings, for the reliability of non-design connections and assemblies. Deviations from the KM drawings must be agreed with the project developer.

3.7 The manufacture of structures should be carried out in accordance with the requirements of working drawings KM and KMD, GOST 23118, SP 53-101-98, technological maps of the manufacturer; installation in accordance with the project for the production of works, SNiP 3.03.01 and this standard.

3.8 In the process of manufacturing and installation of structures, control over the fulfillment of the requirements of this standard should be provided with the results of the control recorded in the factory acceptance documentation, as well as in the executive documentation for installation work.

3.9 The quality control of the manufacture of structures is carried out by the quality control department of the manufacturing enterprise, installation - by line engineering and technical personnel.

4 Manufacturing

4.1 Materials

4.1.1 Depending on the degree of responsibility of individual groups of structures of buildings and structures, as well as on the conditions of their operation and the climatic area of ​​\u200b\u200bconstruction, sheet and shaped steel products according to Table 50 and 51 SNiP II-23-81* (2000 edition).

4.1.2 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 (see clauses 8.4-8.6 of STO 0041-2004).

4.1.3 The applied welding technology and welding consumables shall ensure the values ​​of the tensile strength of the weld metal not lower than the normative values ​​of the tensile strength of the base metal.

4.1.4 The manufacturer of steel structures completes with fasteners in accordance with the requirements of STO 0031-2004. Foundation bolts must comply with GOST 24379.0-80 and GOST 24379.1-80.

4.2 Manufacturing requirements

4.2.1 Before being put into production, rolled products must be checked for compliance with the accompanying documentation, the absence of unacceptable deflections, local dents, cracks, delaminations, and deviations from geometric dimensions.

4.2.2 Cutting blanks of shaped and sheet metal is allowed both mechanically and thermally. In this case, the edges of structural elements working in tension, as well as those made of steel with a normative yield strength of more than 350 MPa, must be machined to a depth of at least 20% of the element thickness.

4.2.3 All holes for bolted field connections must be formed to the design diameter at the steel structure manufacturer, except for those specified in the design documentation.

4.2.4 The formation of holes should be made by drilling on production lines, machine tools with numerical control (CNC), on conductors, and in the absence of equipment - on templates with accuracy in accordance with the KM project or this standard. For non-design structural bolted connections, it is allowed to form holes according to the basting.

4.2.5 In non-rated joints, holes may be formed by punching for steels with a standard yield strength of up to 350 MPa at a ratio of metal thickness t and hole diameter d 0 no more than 0.7 at t≤ 20 mm.

4.2.6 In design connections, it is allowed to punch holes to a smaller diameter, but not more than 0.75 d 0 , with a metal thickness of not more than 0.8 d 0 followed by reaming to design diameter d 0 .

4.2.7 The maximum deviation of the hole diameter should not exceed + 0.6 mm for holes up to 28 mm in diameter and + 0.9 mm over 28 mm.

4.2.8 The maximum deviations of the hole centers are established by the design documentation, based on the condition of the assembly of structures at the installation.

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

4.2.10 Maximum deviation of the dimensions of the connected elements l should be no more than ± 3.0 mm at l≤ 6 m and ± 0.5 mm per meter of length with l> 6 m

4.2.11 The thickness of the overlays must not exceed:

For M12 bolts - 12 mm;

For M16 bolts - 16 mm;

For M20 bolts - 20 mm;

For M24 bolts - 25 mm;

For M27 bolts - 30 mm.

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

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.

4.2.13 For flange connections, the following combinations of bolt diameters and flange thicknesses should generally be used:

M20 - 20 mm;

M24 - 25 mm;

M27 - 30 mm.

4.2.14 The assembly of structural elements with flange connections should be carried out in conductors. The base surfaces of the conductors and the outer surfaces of the flanges after welding must be milled. The tangent of the deflection angle of the flange surface must not exceed 0.0007 in each of the two planes.

4.2.15 Shipping marks of structures shall be primed or painted (by agreement with the customer) except for the contact surfaces of friction and friction-shear joints, as well as the contact surfaces of flanges, if this is stipulated by the project documentation.

4.3 Check assembly

4.3.1 Test assembly of structures with bolted connections should be carried out at the manufacturer if it is specified in the design documentation.

4.3.2 Control assembly of structures is carried out in accordance with the requirements of the design and technological 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 pass through 100% of the holes in each joint.

4.3.3 The gaps between the connected elements are controlled by a 0.3 mm thick probe, between the flanges - by a 0.1 mm thick probe. The probe must not penetrate into the area limited by a radius of 1.3 d 0 from the axis of the bolt after tightening all the bolts of the connection to the design force.

5 Mounting

5.1 Assembly requirements for connections

5.1.1 Work on the construction of buildings and structures with bolted connections should be carried out in accordance with the approved project for the production of works (PPR), working documentation and SNiP 3.03.01-87.

5.1.2 Data on the production of installation work should be entered daily in the logs of work on installation and making connections on bolts with controlled tension ().

5.1.3 The structures used must comply with the requirements of the working drawings, and the hardware must comply with the standards or specifications specified in STO 0031. Each batch of bolts, nuts and washers must be provided with a quality certificate indicating the results of mechanical tests.

5.1.4 In case of doubts about the quality of the supplied fasteners, an incoming inspection of geometric dimensions or mechanical properties is carried out, which includes testing the bolts for hardness and rupture with the determination of the actual values ​​of temporary resistance, nuts for test load and hardness, washers for hardness and non-flatness. The thread quality of bolts and nuts is controlled by thread gauges in accordance with GOST 18107.

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

5.1.6 When assembling mounting elements, the stability and invariability of their position in space at all stages of installation should be ensured.

5.1.7 The execution of connections on bolts with controlled tension (friction, friction-shear and flange connections) and their acceptance should be carried out under the guidance of a person appointed responsible for the implementation of this type of connection by order of the organization performing these works. Only personnel who have undergone appropriate training and have a certificate of admission to the specified work are allowed to perform connections. The recommended training program and form of certification are given in.

5.1.8 The technological process of making connections provides for the following operations:

Preparation of bolts, nuts and washers;

Preparation of contact surfaces of elements and parts;

Assembly of connections;

Bolt tension for design force;

Quality control of connections;

Sealing of joints and priming of joints;

Installation of the stigma of the foreman and responsible person;

Entering the results of the implementation and quality control of the connections in the "Journal of the implementation of field connections on bolts with controlled tension" ().

5.2 Preparing bolts, nuts and washers

5.2.1 The technological process of preparing bolts, nuts and washers intended for joints with controlled bolt tension includes depreservation, cleaning from dirt and rust, threading of rejected bolts and nuts and applying lubricant.

5.2.2 Depreservation of bolts, nuts and washers and application of lubricant to bolts and nuts should be carried out by boiling in water (10÷15 min) followed by hot washing in a mixture consisting of 70÷75% unleaded gasoline and 30÷25% mineral oils in accordance with GOST 20799. The applied ratio of gasoline and oil should provide a thin layer of lubricant on the surface of bolts and nuts.

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

5.2.4 Prepared hardware should be stored in closed boxes without access to atmospheric precipitation for no more than 10 days, since with longer storage, the lubricant evaporates, friction in the thread increases, and the tension force of the bolts decreases.

1 - washing bath; 2 - lifting device; 3 - bath for boiling;

4 - containers; 5 - pallet; 6 - stand

Figure 1 - Hardware preparation post

5.2.5 To drive the threads of rejected bolts and nuts, it is recommended to use suitably equipped pneumatic or electric wrenches, as well as taps and dies of the appropriate diameter.

5.2.6 In case of exceeding the storage period, as well as after threading, the hardware must be processed again.

5.2.7 Estimated consumption of gasoline per 100 kg of hardware is 2.2 liters, oil - 0.8 liters.

5.2.8 As a thread lubricant, it is allowed to use hard grades of paraffin in accordance with GOST 23683. Cleaning of bolts, nuts and washers from factory preservative grease 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 nuts preheated to a temperature of at least +80°C. The consumption of paraffin is 3÷4 g per 1 kg of fasteners. Detailed technology is given in the "Recommendations for the use of high-strength bolts coated with a paraffin-based composition in field joints of steel structures", Moscow, 1989.

5.2.9 Preparation of hardware with metal coatings is allowed by lubricating the nut threads by dipping them into a container with mineral oil in accordance with GOST 20799 no later than 8 hours before assembling the joints, followed by determining the value of the torque coefficient ( To h) with the help of dynamometric control devices. Installation of bolts with a broken coating, with traces of rust or with To h > 0.2 is not allowed.

5.3 Preparation of contact surfaces

5.3.1 The method of processing the contact surfaces of friction, friction-shear and flange joints is indicated in the KM or KMD drawings.

5.3.3 The contact surfaces of the elements of connections on bolts without controlled tension must be cleaned of contamination with metal brushes.

5.3.4 Treated surfaces should be protected from dirt, oil and paint, as well as from the formation of ice. Dirt is removed with metal brushes, oil with solvents, paint and ice with heat.

5.3.5 In case of exceeding the period from the moment of preparation of the contact surfaces to the assembly of the connection for more than 3 days, it is necessary to re-process in the manner used during the primary processing.

5.3.6 The requirements for re-treatment do not apply to rust deposits formed on the contact surfaces after their cleaning, as well as in case of contact with precipitation in the form of moisture or condensation of water vapor.

5.3.7 Re-fire treatment is allowed instead of pneumatic, while propane can be used as a combustible gas.

5.4 Assembling connections

5.4.1 The technological process of assembling joints provides for:

Inspection of structures and verification of compliance of the geometric dimensions of the assembled elements with the requirements of working drawings;

Alignment of holes and fixation in the design position of the elements and parts of the connection using mounting mandrels;

Setting bolts in holes free from mandrels;

The tension of the supplied bolts to the force provided for in the project;

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

It is not allowed to install bolts in holes formed by manual gas cutting or welding.

5.4.2 The difference in the thicknesses of the elements covered by the overlays, determined before the installation of the overlays with the help of a ruler and a feeler gauge, should not exceed 0.5 mm.

5.4.3 If the difference in the planes of the connected elements is from 0.5 to 3.0 mm, to ensure a smooth bending of the lining, the edge of the protruding element should be removed with an emery stone at a distance of at least 30 mm from the edge. With a difference of more than 3.0 mm, gaskets should be used. The use of gaskets must be agreed with the project developer,

5.4.4 Blackness (misalignment of holes in individual parts assembled package) should not exceed the difference between the nominal diameters of holes and bolts and should not interfere with the free, without distortion, placement of bolts in holes.

5.4.5 In the assembled package, the bolts of the diameter specified in the project must pass through 100% of the holes. It is allowed to clean 20% of the holes with a drill or a conical reamer, the diameter of which is 1.0 mm larger than the nominal diameter of the bolt.

5.4.6 It is forbidden to use bolts in design connections that do not have the manufacturer's stamp and marking indicating the strength class.

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

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

5.4.9 At the time of installation of the bolts, the nuts must be screwed freely by hand along the thread, otherwise the nut or bolt should be replaced, and the rejected bolts and nuts should be sent for threading and re-preparation.

5.4.10 When calculating connections for the action of mounting loads, the work of mandrels and bolts may be taken into account together. The number of mandrels and bolts at each stage of the connection device should be taken into account for the action of mounting loads.

5.4.11 The number of mandrels according to the condition of matching the holes should be 10% of the number of holes in the connection, but not less than 2 pieces, and the number of tie bolts - 15÷20%.

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

5.4.13 Places and stages of installation of mandrels are indicated in the project for the production of works, and the sequence of bolt tension - in accordance with.

5.4.14 The lengths of the bolts of friction and flange connections are assigned depending on the total thickness of the assembled package in accordance with Table 1. In this case, the thread protruding above the nut must have at least one, and at least two turns with a full profile must remain under the nut.

5.4.15 The lengths of the bolts of friction-shear and shear joints are selected so that the thread does not fall in the shear plane and is at least 5 mm away from the nearest of them or at least half the thickness of the element adjacent to the nut.

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

Table 1

Bolt length, mm	Thickness of the package, subject to the installation of two washers, for bolts with a diameter, mm
	0÷ 10
	13÷ 20	0÷16	0÷12
	23÷ 30	16÷26	8÷22	0÷18	0÷14	0÷11
	33÷40	26÷36	18:32	15:28	11:24	6÷21	0÷18
	43÷50	36÷ 46	28÷42	25÷38	21÷34	16:31	10÷28	0÷20
	53÷60	46÷56	38÷52	35÷48	31÷44	26÷41	20÷38	8÷30	0÷24
	63÷70	56÷66	48÷62	45÷58	41÷54	36÷51	30÷48	18:40	8÷34	0÷30
	73÷80	66÷76	58÷72	55÷68	51÷ 64	46÷61	40÷58	28÷50	18:44	6÷40
	93÷100	86÷96	78÷92	75÷88	71÷84	66÷81	60÷78	48÷70	38÷64	20÷60
		106÷116	98÷112	95÷108	81÷104	86÷ 101	80÷98	68÷90	58÷84	40÷80
		126÷136	118÷132	115÷128	111÷124	106÷121	100÷ 118	88÷110	78÷104	60÷100
			138÷152	135÷149	131÷144	126÷141	120÷ 138	108÷130	98÷124	80÷120
				155÷168	151÷164	146÷161	140÷158	128÷150	108÷144	100÷140
					171÷184	166÷181	160÷178	148÷ 170	128÷164	120÷160

5.5 Bolt tension

5.5.1 The tension of the bolts to the design force is ensured by adjusting the forces according to the torque.

5.5.2 Bolts should be tensioned from the middle of the connection or from its most rigid part towards the free edges. If the total thickness of the connected elements exceeds 2 bolt diameters, the number of bypasses must be at least two.

5.5.3 If, when the bolt is tightened, the nut turns without increasing the torque, then the bolt and nut must be replaced.

5.5.4 Bolts can be tensioned both by the nut and by the bolt head. Nuts or bolt heads tightened to design force are marked with paint or chalk.

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

the package is tightly tightened by tensioning 15÷20% of the supplied bolts (coupling) to 80÷100% of the design force, evenly distributing them over the connection field, while the location of the coupling bolts in the immediate vicinity of the mandrels is mandatory;

all supplied bolts, including coupling bolts, are tightened to the design force;

the mandrels are replaced with bolts and tightened to the design force.

5.5.6 When adjusting forces, the calculated value of the torque for various diameters and strength classes of bolts is determined by the formula

where R- the value of the axial tension force of the bolts specified in the project;

d- nominal diameter of the bolt;

K h - tightening factor of bolts and nuts, taken equal to 0.175 for bolts supplied in accordance with GOST 22353 and GOST 1759.4 and prepared in accordance with;

K n = 1.05 - reliability coefficient.

5.5.7 Due to the lack of statistical data, the value of the torque factor for bolts, nuts and washers with metal, paraffin or other types of coatings, as well as those supplied according to others not specified in clause 5.5.6 of this standard, should be established experimentally for each batches of bolts and nuts with the help of dynamometric control devices on certified equipment.

5.5.8 The values ​​of the axial tension forces of the bolts, calculated according to the formula (6) STO 0041-2004, as well as the tightening torques of the bolts with a diameter of 12÷27 mm, calculated according to the formula (1), are given in Table 2.

5.5.9 Pre-tensioning of bolts up to 80÷90% of the design value is recommended to be done with wrenches, followed by tightening with torque wrenches. When the number of bolts in the connection is not more than 4 and in hard-to-reach places, the tension of the bolts with torque wrenches is allowed at one time.

table 2

Bolt strength classes	Nominal bolt diameters, mm	Bolt tension force, kN (tf)	Twisting moments M h, H m (kgf m) at the value of the twisting coefficientK h = 0.175
High strengthGOST 22353		118 (12,0)	330 (34)
		184 (18,8)	644 (66)
		229 (23,4)	882 (90)
		266 (27,1)	1117 (114)
		346 (35,3)	1634 (167)
		61 (6,2)	128 (13)
		114 (11,6)	319 (33)
		178 (18,2)	623 (64)
		49 (5,0)	103 (11)
		91 (9,3)	255 (26)
		142 (14,5)	497 (51)

5.5.10 The torque transmitted by the key must be recorded during the movement of the key in the direction that increases the bolt tension. Tightening should be done smoothly, without jerks.

5.5.11 Torque wrenches must be numbered and calibrated. Keys should be calibrated before the start of the shift using the STP-2000 stand or another type of device, or test weights in accordance with GOST 8.541 clause 2.1.1 (). Calibration results must be recorded in the key calibration log ().

5.5.12 The deviation of the actual value of the torque from the calculated one should not exceed +15%. Undertightening of bolts is not allowed.

5.5.13 The main technological operations when making bolted connections are given in the mandatory "Typical technological process bolted connections.

5.6 Making bolted connections without controlled tension

5.6.1 When making connections on bolts without controlled tension, bolts, nuts and washers are installed in the connections without removing the factory preservative lubricant, and in its absence, the threads of the bolts and nuts are lubricated with mineral oil according to GOST 20799.

5.6.2 The contact surfaces of the elements and parts before assembling the joints must be inspected and cleaned from burrs, dirt, loose rust, loose scale and ice. Cleaning is carried out in accordance with paragraphs. , . Burrs are removed with electric or pneumatic grinders.

5.6.3 Assembly of connections is carried out in accordance with the requirements set forth in section 5.4. The bolts are tightened to failure with mounting wrenches with a force of 294 N (30 kgf) ÷ 343 N (35 kgf) and a handle length of 200 ÷ 250 mm for M12 bolts, 300 ÷ 350 mm - M16, 350 ÷ 400 mm - M20, 400 ÷ 450 mm - M22, 500÷550 mm - M24, 550÷600 mm - for M27 bolts.

5.6.4 To prevent self-unscrewing, the nuts are additionally secured by setting special washers or locknuts. For bolts in tension, fastening of nuts should be carried out exclusively by setting locknuts. It is forbidden to weld nuts to the threads of bolts and to the elements of connections, as well as driving a thread protruding from the nut.

5.6.5 In structures that perceive static loads, the nuts of bolts tightened to a force exceeding 50% of the calculated tensile strength may not be additionally secured.

5.6.6 Nuts and heads of bolts, including foundation bolts, after tension, should be in close contact (without gaps) with the planes of washers or structural elements, and the bolt shafts protrude from the nuts (locknuts) by at least one thread with a full profile. The tightness of the screed of the assembled package should be checked with a probe 0.3 mm thick, which should not penetrate into the area limited by a radius of 1.3 d 0 from the center of the bolt, where d 0 - nominal hole diameter.

Foundation (anchor) bolts must be tightened in accordance with the requirements of SNiP 2.09.03-85, appendix 2.

5.6.7 The quality of bolt tightening without controlled tension is checked by tapping them with a hammer weighing 0.4 kg, while the bolts should not move. It is allowed to tighten the bolts and control the tension with limit torque wrenches.

5.7 Quality control, acceptance and sealing of joints

5.7.1 The quality of bolted connections is checked by carrying out step-by-step control. When accepting work, the quality of preparation of contact surfaces, the accuracy of bolt tension, the density of the tightened package, as well as the compliance of the geometric dimensions of the assembled structures with the requirements of working drawings of the KM in the KMD are controlled.

5.7.2 The quality of the preparation of the contact surfaces of the elements and parts to be joined (linings, gaskets) is controlled visual inspection just before assembling connections. Defective surfaces or areas thereof are subject to correction in accordance with section 5.3 of this standard.

5.7.3 The method of controlling the actual value of the axial bolt tension force is assigned the same as when adjusting their tension forces.

5.7.4 Regardless of the method of force regulation, the inspector (responsible person) must, first of all, make an external inspection of all supplied bolts and make sure that all bolts of the connection have the specified marking and the same length; washers are installed under all bolt heads and nuts (with the exception of p.p. ÷); the parts of the bolts protruding beyond the nut have at least one thread with a full profile above the nut or two threads under the nut (inside the package); axial tensile forces of the bolts correspond to those specified in the project; on the assembled node there is a brand of the team that performed these works, and the results are recorded in the log of the execution of connections on bolts with controlled tension.

5.7.5 The number of bolts subject to control of axial force (torque) should be:

With the number of bolts in the connection up to 5 pcs. - all bolts;

6 and more - 15%, but not less than 5 pieces.

5.7.6 During the control, the actual value of the twisting moment shall not be less than the calculated value and shall not exceed it by more than 15%.

5.7.8 The representative of the customer who accepts the work performed is given the right additional control 10% of bolts with a torque wrench.

5.7.9 If the test results for at least one bolt do not match, double the number of bolts is controlled. If, in this case, an undertightened bolt is detected, all the bolts of this connection are controlled. The tension of all bolts must be brought to the calculated value.

5.7.10 The tightness of the package tie is controlled by a probe 0.3 mm thick opposite the tightened bolt. In this case, the probe should not penetrate into the zone limited by a radius of 1.3 d 0 from the bolt axis, where d 0 - nominal hole diameter.

5.7.11 The results of the control, regardless of the method of adjusting the bolt tension forces, should be recorded in the journal ().

5.7.12 In the absence of comments, next to the brand of the brigade, the brand of the foreman is installed. If the bolts or nuts are prepared by paraffin waxing, the “P” stamp is additionally put. Types and sizes of stamps must comply with GOST 25726.

5.7.13 After the joints are accepted by the inspector, all joint surfaces, including bolt heads, nuts and washers, including the contours of the overlays, must be primed, and the gaps filled with sealant or mounting foam. Mark the location of the stamps with white paint with a size of at least 100 × 100 mm.

Annex A
(mandatory)

Design of covers and pages of the magazine for performing field connections on bolts with controlled tension

Title page Magazine making field connections on bolts with controlled tension №_______ Name of the organization performing the work __________________________________ Name of the construction object _____________________________________________ Position, surname, initials and signature of the person responsible for the performance of work and keeping a log ______________________________________________________________ The organization that developed project documentation, KM drawings ____________________ ____________________________________________________________________________ The organization that developed the project for the production of works ______________________________ ____________________________________________________________________________ Project code ________________________________________________________________ The enterprise that developed the KMD drawings and manufactured the structures _________________ ____________________________________________________________________________ Order code _________________________________________________________________ Customer (organization), position, surname, initials and signature of the head (representative) of technical supervision _____________________________________________ ____________________________________________________________________________ The journal was started on "___" _____________ 200__. The journal ended on "___" _____________ 200__.

1st page

List of linkmen (installers) involved in the installation of bolts

Full Name	Assigned category	Assigned number or sign (brand)	Qualification certificate		Note
			date of issue	issued by whom

2nd and subsequent pages

the date	KMD drawing number and name of the node (joint) in the connection	Bolt setting				Control results
		number of supplied bolts in the connection, pcs.	bolt certificate number	method of processing contact surfaces	design torque, kgf m	quality of contact surfaces	number of tested bolts, pcs	torque test results, kgf m	stamp number, foreman's signature	signature of the person responsible for setting the bolts	signature of the client's representative

3rd cover page
Numbered and laced in the magazine
Pages
"____" __________________ 200___
(position, surname, initials and signature of the head of the organization that issued the magazine)
Place
printing

Training program for installers and engineers on the implementation and acceptance of bolted connections (20 hours)

1. Types of connections, features of the operation of connections with and without controlled
controlled bolt tension 2 hours

2. Materials, products and conditions for their use2 hours

3. Technology for making connections on bolts with controlled tension:

theoretical lessons3 hours

practical training3 hours

4. Applied devices, tools and fixtures 2 hours

5. Acceptance and sealing of joints2 hours

6. Technical as-built documentation1 hour

7. Safety 2 hours

8. Certification and issuance of certificates3 hours

After training on a 20-hour program, certification is carried out and a certificate is issued for the right to perform work for a period of 1 year.

ID form

Recheck details:

a photo

Position

Place of work

M.P.

Certificate No.

After checking the knowledge, he was allowed to perform field connections on bolts with controlled tension.

Issued

(Full Name)

Protocol dated "__" ___________ 200__ No.__

Position

Place of work

Valid until "___" ________ 200__.

in that, after checking the knowledge, it is allowed to perform field connections on bolts with controlled tension.

Protocol dated "__" ___________ 200__ No.__

Valid until "__" __________200__.

Commission Chairman

Commission Chairman

(Full name.)

(Full name.)

Commission member

Commission member

(Full name.)

(Full name.)

MP.

Method for determining the twist factor K h

Determining the actual value K z for a batch of bolts, nuts and washers should be made on a UTB-40 hydraulic dynamometric device or other certified equipment that allows you to simultaneously record the amount of axial force in the bolt shaft R and the torque applied to the nut M h.

Value K h for a batch of bolts and nuts is determined by formula (1) and is taken as the arithmetic mean value based on the test results of 5 pieces of bolts, nuts and washers.

where d- nominal bolt diameter, mm;

Axial force in the bolt shaft, kN;

The smallest tensile strength of the bolt, kN/mm;

Net cross-sectional area of ​​the bolt, mm 2 .

Determination results K h are drawn up in a protocol or act.

1 - piston; 2 - body; 3 - flange;

4 - pressure gauge; 5 - tested bolt

Figure 1B - General form devices UTB-40

Annex D
(mandatory)

Torque wrench calibration

G1. Torque wrenches are calibrated using special calibration stands or test weights (weights) in accordance with GOST 8.541-86 clause 2.1.2.

Calibration of limit or control (indicator) keys with loads is carried out in the following order. A key is hung on a hexagonal mandrel or on a tightened high-strength bolt so that its handle with a suspended load is in a horizontal position (Figure 1D). At a fixed point at the end of the key, a set of weights with a total mass of m is suspended. The weight of each weight should not exceed 10÷15 kgf (98÷147 N). Each load is marked with its mass to the nearest 0.1 kgf (0.98 N).

For limit wrenches weight m, at which the key is triggered, will be:

where M h - design twisting moment (clause 5.5.6);

Δ M h - a moment equal to the product of the mass of the key and the distance from the center of its gravity to the axis of rotation of the key;

l- distance from the point of application of the load to the axis of rotation of the key.

When calibrating indicator keys before hanging loads, the arrow measuring device is set to "0". After hanging loads with a mass m the reading is taken from the measuring device and the division value of the device is determined, equal to

where M h = m l- estimated twisting moment;

n- indications of the measuring device.

The measurements are repeated 2÷4 times until a stable result is obtained.

Calibration results are recorded in the key calibration log ().

G2. The applied torque wrenches must comply with GOST R 51254 and provide the limit of the basic permissible error from the measured value not less than the value determined by the equation

where K= 35 with a confidence level of measurement results equal to 0.95.

1 - support; 2 - welded hexagon,

3 - calibrated key; 4 - calibration weight

Figure 1D - Calibration of keys

With a tightening tolerance of 15% (clause 5.7.6), the permissible error in the measurements of the keys Δ will be

For keys with a measurement limit up to 130 kgf ∙ m (1274 Nm) and length l= 1.5 m measurement error Δ when calibrated by loads weighing up to 10÷15 kgf (98÷147 N) and weighed with an accuracy of 0.1 kgf (0.98 N) will be

(name of the construction site)

_____________________________________________________________

(location of the object)

Magazine

control calibration of torque wrenches

the date	Key		Cargo weight, n (kgf)	Moment from the control load, nm (kgf m)	Indications on the device *, cases.	Foreman's signature
	type	room
* - when calibrating the limit keys in the column "Indications on the device" the entry "key actuation" is made.

Annex E
(mandatory)

Typical workflow for making bolted connections

No. p / p	Name of technological operations	Required Tools, Equipment and materials
	Preparing bolts, nuts and washers
	Clean and lubricate bolts, nuts and washers by boiling in water for 10-15 minutes followed by hot immersion in a mixture of 70-75% unleaded gasoline and 30-35% mineral oil	Lattice containers up to 30 l. Capacity for 40÷ 100 l. Gasoline 2.2 l, oil 0.8 l per 100 kg of hardware
	Before applying the paraffin coating, clean the bolts, nuts and washers from preservative grease by boiling in water with the addition of detergent MS-18, MS-15 or soda ash with a concentration of 15÷ 30 g/l	Lattice containers up to 30 l. Capacity for 40÷ 100 l
	Apply a paraffin coating to fasteners (bolts, nuts and washers or single nuts) preheated in a cleaning solution. The temperature of fasteners should not be lower than 80°C, of ​​paraffin composition - 70÷ 80°C	Bath with molten paraffin. Paraffin consumption is 3÷ 4 g/kg
	Place prepared bolts, nuts and washers (separately) in a special portable container. The shelf life of prepared hardware is: lubricated with mineral oil or washed in a cleaning solution for no more than 10 days; with paraffin coating - up to 4 months.	Closed boxes for supplying hardware to workplace
	Preparation of contact surfaces
	Remove burrs around holes and along the edges of elements and parts with the flat side of a grinding stone. Eliminate staggering of connected elements	grinder
	Treat the contact surfaces of the connected elements and parts, including gaskets, in the manner specified in the project
	Record the results of the preparation of contact surfaces in a journal () and present them for control to the responsible person
	Connection assembly
	Check the absence of local curvatures on the connected elements and parts, compliance of the geometric dimensions with the requirements of the working drawings	Steel ruler 1 m long, tape measure
	Make sure that there are no traces of oil on the contact surfaces, as well as burrs around the holes and along the edges of the parts. If necessary, re-process the contact surfaces
	Install the linings in the design position and fix the relative position of the parts with assembly plugs in the amount of 10%, but not less than two of the number of holes and coupling bolts	Assembly plugs, hammer, colic and open-end wrenches
	Align structural elements in space	Roulette, ruler, theodolite, level
	In case of mismatch, clean up to 20% of the holes with a conical reamer with a diameter not less than the nominal diameter of the bolts and not more than the nominal diameter of the holes	Conical reamers, drilling machine
	Fill free holes with bolts of the required length, placing one washer under the bolt heads and nuts	Mounting spanners, boxes of hardware with a tag indicating the date of preparation
	Torque bolt tension
	Calibrate the torque wrenches on the stand or using test weights ()	Calibration stand, set of weights weighing 10÷ 20 kg each
	Tighten the nuts to the calculated torque. Pre-tensioning can be done with a wrench that creates a bolt tension 0÷10% lower than the calculated one.	Torque wrench, wrench
	Record the results of the bolt tension in a journal (), set the brand of the brigade on the assembled unit, present the connections to the responsible person for control	Hammer, stamp on GOST 25726
	Quality control making connections
	Check the tightness of the package screed with a probe 0.3 mm thick	Probe 0.3 mm
	Check that the installed bolts comply with the requirements of the project	Visually
	Check the tension of the bolts in each connection in the amount of 15%, but not less than 5 pcs.	Torque wrench
	Record the results of the control in a journal (), next to the stigma of the brigade, establish the stigma of the foreman
	Joint sealing
	Seal the accepted connection, prime the unpainted places, fill the gaps with sealant or mounting foam. Mark the location of the stamp with a white stencil	Brush, primer GF-021 or FL-OZK with the addition of dry pigment, sealant, white paint

Keywords: fasteners, strength class, connection, shear, shear, crush, tension, friction, force, torque

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

Among the shortcomings, one can note a large 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 version of SNiP II-23-81)

SNiP 3.03.01-87 Bearing and enclosing structures

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

STO 0031-2004 Bolted connections. Product range and applications

STO 0041-2004 Bolted connections. Design and calculation

STO 0051-2006 Bolted connections. Manufacturing and installation

Types of bolted connections

According to the number of bolts: single-bolt and multi-bolt. I don't think it needs to be explained.

By 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 it works in the general case. bolted connection when working on a cut.

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

The calculation of non-shear 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 resulting friction forces. Such a connection is called a connection without controlled tension of the bolts.

Shear or friction joints use high-strength bolts that tighten the plates with such a force that the load Q is transferred through frictional forces between the 2 plates. Such a connection can be friction 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 implement it in practice in a multi-bolt connection - there is no certainty that all the bolts can simultaneously bear the load on the shear, therefore it is better to calculate the friction connection without taking into account the shear.

At high shear loads, a friction connection is more preferable. the metal content 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 smaller in diameter and gradually reamed to desired diameter. The diameter of the hole in such connections should not exceed the diameter of the bolt by more than 0.3 mm. It is extremely difficult to make such a connection, therefore, in building structures they are practically not used.

Bolts of accuracy class B (normal accuracy) and C (coarse accuracy) are installed in holes 2-3 mm larger than the diameters of the bolts. The difference between these bolts is the bolt diameter error. For bolts of accuracy class B, the actual diameter may 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, as a rule, bolts of accuracy class B are used. in the realities of installation on a construction site, it is almost impossible to achieve high accuracy.

Types of bolts by strength and their application

For carbon steels, the strength class is indicated by two numbers through 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 digit in the bolt strength classification indicates the tensile strength of the bolt - one unit indicates a tensile strength of 100 MPa, i.e. the ultimate 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 tensile strength in tens of percent - for a bolt of strength class 9.8, the yield strength is 80% of the tensile 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 steel tensile testing. The horizontal axis indicates the change in the length of the test specimen, and the vertical axis indicates the applied force. As you can see from the diagram, with an increase in 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 point, then with a slight increase in load, the bolt stretches more, at point D the bolt breaks - this is the tensile strength . In building structures, it is necessary to ensure the operation of a bolted connection 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 is no marking on the bolts, then most likely these are bolts of a strength class below 4.6 (their marking is not required according to GOST). The use of bolts and nuts without marking is prohibited in accordance with SNiP 3.03.01.

On high-strength bolts, it is additionally indicated symbol swimming trunks.

For the bolts used, it is required 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. It is possible to replace nuts of one strength class with higher ones (for example, if it is more convenient to complete nuts of one strength class for an object).

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

For bolts from of stainless steel also marked on the head of the bolt. 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 \u003d 800 MPa.

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

Choice of bolt steel grade

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

Selection of bolt diameter for constructionstructures

For connections of building metal structures, bolts with a hexagonal head of normal accuracy according to GOST 7798 or increased accuracy according to GOST 7805 with a coarse thread pitch of diameters from 12 to 48 mm of strength classes 5.6, 5.8, 8.8 and 10.9 according to GOST 1759.4, hex nuts of normal accuracy according to 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 execution of 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 so as to provide the necessary 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 the use of such a connection is not recommended 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 from the following table:

Bolt spacing

Distances when placing bolts should be taken in accordance with Table 40 of SP 16.13330.2011

In joints and nodes, bolts must be located closer to each other, and structural connecting bolts (used to connect parts without transferring significant loads) at maximum distances.

It is allowed to fasten parts with one bolt.

Choice of bolt length

We determine the length of the bolt as follows: add up the thicknesses of the elements to be joined, the thicknesses of the washers and nuts, and add 0.3d (30% of the bolt diameter) and then look at the assortment and select the nearest length (rounded up). According to building codes the bolt must protrude from the nut by at least one turn. A bolt that is too long cannot be used. there is a thread only at the end of the bolt.

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

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

Here's an example:

The bolt works in 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 accepted.

The minimum length of the bolt is: 2x12 + 3 + 5 + 16 + 0.3x20 = 54 mm, according to GOST 7798-70, we select the 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 deep into the hole by no more than 5 mm, so we increase the length of the bolt to 2x12 + 46-5 = 65 mm. According to the norms, an M20x65 bolt can be accepted, 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 (very often this is 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 required to use a 2nd nut or lock washers to prevent unscrewing of the bolts and nuts. If the bolt is in tension, then a 2nd bolt must be used.

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

Do not use spring washers for oval holes.

Washer installation

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) connection working in tension;

2) shear connection;

3) connection working on shear and tension;

4) friction connection (working in shear, but with a strong bolt tension)

Calculation of a bolted connection in tension

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

where Nbt is load bearing capacity one tensile bolt;

Rbt is the design tensile strength of the bolt;

Calculation of a bolted shear connection

If the connection works on a slice, then you need to check 2 conditions:

shear calculation according to formula 186 SP 16.13330.2011

where Nbs is the bearing capacity of one bolt per shear;

Rbs is the design shear strength of the bolt;

Ab is the gross sectional area of ​​the bolt (accepted in accordance with Table D.9 of 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 one, if 3, then 2, etc.);

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

γc is the coefficient of working conditions, taken according to Table 1 of SP 16.13330.2011.

and calculation for collapse according to the formula 187 SP 16.13330.2011

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

Rbp is the design bearing strength of the bolt;

db- outside diameter bolt shaft;

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

γb is the coefficient of the working condition of the bolted connection, taken in accordance with Table 41 of SP 16.13330.2011 (but not more than 1.0)

γc is the coefficient of working conditions, taken according to Table 1 of SP 16.13330.2011.

Design resistance of bolts can be determined according to Table D.5 of SP 16.13330.2011

The design resistance Rbp can be determined from Table D.6 of SP 16.13330.2011

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

Calculation of a connection working in shear and tension

With the simultaneous action on the bolted connection of forces that cause shear and tension of the bolts, the most stressed bolt, along with the check according to the formula (188), should be checked according to the 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 of SP 16.13330.2011

Friction connection calculation

Friction joints, in which forces are transmitted through friction that occurs on the contacting surfaces of the elements to be joined due to the tension of high-strength bolts, should be used: in steel structures with a yield strength of more than 375 N / mm² and directly perceiving moving, vibrational 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 taken by each friction plane of elements tightened by one high-strength bolt should be determined by formula 191 SP 16.13330.2011

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

Abn is the net cross-sectional area (accepted in accordance with Table D.9 of SP 16.13330.2011);

μ is the coefficient of friction between the surfaces of the parts to be joined (accepted according to Table 42 of SP 16.13330.2011);

γh is the coefficient taken according to Table 42 of SP 16.13330.2011

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

where n is the required number of bolts;

Qbh is the design force that one bolt takes (calculated according to the formula 191 SP 16.13330.2011, described a little higher);

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

γc is the coefficient of working conditions, taken in accordance with Table 1 of SP 16.13330.2011;

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

0.8 at n< 5;

0.9 for 5 ≤ n< 10;

1.0 for n ≤ 10.

Designation of a bolted connection in the drawings

measurement of low resistance values ​​with a resolution of 1 μΩ with an operating current from 0.1 mA to 10 A: welded and equipotential joints; clamps, terminals, connectors; welded rails; conductors of cables and wires; windings of transformer motors; low resistance coils;

automatic discharge of inductance after measurement;

checking the continuity of the grounding conductor and the quality of all connections;

three ways to start measurements: normal (one measurement of active resistance); automatic (activation when all four measuring wires are connected to the object); continuous (measurement one after another continuously with the result displayed after three seconds);

high noise immunity;

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

STATE STANDARD OF THE UNION OF THE SSR
CONNECTIONS CONTACT ELECTRIC
Classification. General technical requirements
Electrical contact connections. classification.
General technical requirements
GOST 10434-82

Date of maintenance 01.01.83

This standard applies to demountable and non-separable electrical contact connections of tires, wires or cables (hereinafter referred to as conductors) made of copper, aluminum and its alloys, steel, aluminum-copper wires with leads of electrical devices, as well as to contact connections of conductors to each other for currents from 2, 5 A. For contact connections electrical devices for currents less than 2.5 A, the requirements of the standard are recommended. The requirements of the standard in terms of the permissible value of electrical resistance and resistance of contact connections with 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 electrical devices for special purposes.

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

1. CLASSIFICATION

1.1. Depending on the field of application, electrical contact connections (hereinafter referred to as contact connections) are divided into classes in accordance with Table. one.

Table 1

Scope of contact connection	Contact connection class
1. Contact connections of circuits, the sections of the conductors of which are selected according to the permissible long-term current loads (power electrical circuits, power lines, etc.)	1
2. Contact connections of circuits, the sections of conductors of which are selected for resistance to through currents, loss and voltage deviation, mechanical strength, overload protection. Contact connections in circuits of grounding and protective conductors made of steel	2
3. Contact connections of circuits with electrical devices, the operation of which is associated with the release a large number heat ( heating elements, resistors, etc.)	3

Note. in standards and specifications for specific types of electrical devices, classes 2 and 3 should be indicated, class 1 is not indicated.

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

1.3. By 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, collapsible 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 for stabilizing electrical resistance - see paragraphs. 2.1.7 and 2.1.8.

table 2

Climatic version and placement category of the electrical device
1. All climatic versions for location category 4.1 with atmosphere types II and I. Climatic modifications U, UHL, TS for placement category 3 and climatic modifications UHL, TS for placement category 4 with atmosphere types II and I	BUT
2. Any combination of climate version and location category, other than those indicated above, with atmosphere types II and I. Any combination of climate version and placement category with atmosphere types III and IV	B

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 specifications for specific types of electrical devices according to working drawings approved in the prescribed manner.

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

2.1.3. Contact screw clamps must comply with the requirements of GOST 25034-85, terminal clamps 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. Non-separable contact connections must be made by welding, soldering or crimping. It is allowed to use other methods specified in the standards or specifications for specific types of electrical devices.

Examples of making non-separable contact connections are given in Appendix 1.

2.1.6. Collapsible contact connections that do not require the use of electrical resistance stabilization means 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. Detachable contact connections requiring the use of means for stabilizing electrical resistance must be made using the following means either individually or in combination:

1) fasteners made of non-ferrous metals with a linear expansion coefficient from 18 10 -6 to 21 10 -6 1/°C;
2) Belleville springs in accordance with GOST 3057-90 or specifications for specific types of springs;
3) protective metal coatings of working surfaces, selected in accordance with 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 specifications for specific types of electrical devices;
4) transition parts in the form of copper-aluminum plates according to GOST 19357-81, copper-aluminum lugs according to GOST 9581-80 and hardware clamps made of clad aluminum according to 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 the test results in accordance with GOST 17441-84 and is indicated in the standards or specifications for specific types of electrical devices.

When using means 2)-8), contact connections, as a rule, should 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 on the working surfaces of copper conductors should be specified in the standards or specifications for specific types of electrical devices.

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

2.1.8. Collapsible 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 to each other - 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 connection group	Conductor material	Standard item number depending on the material of the output or the second conductor
		copper and its alloys	solid aluminum alloy	aluminum	steel
BUT	Copper, aluminum copper	2.1.6			2.1.6
	Solid aluminum alloy
	Aluminum	2.1.7 1) or 2) or 3) or 4) or 5) or 8)
B	Copper, aluminum copper	2.1.6			2.1.6
	Solid aluminum alloy	2.1.7* 3) or 4) or 5) and 3)	2.1.6		2.1.7 4) or 5) and 3)
	Aluminum	2.1.7 4) or 5) and 3) or 1) and 3) or 2) and 3)	2.1.7 1) or 2) or 3) or 4) or 5)

Contact connections in accordance with the climatic version and category of placement of electrical devices, determined in accordance with GOST 15150-69 and GOST 15543-70, must withstand the effects of climatic factors external environment specified in GOST 15150-69, GOST 15543-70, GOST 15963-79, GOST 16350-80, GOST 17412-72 or in standards and specifications for specific types of electrical devices.

Table 4

Contact connection group	Conductor material	Standard item number depending on the material of the pin
		copper or brass for rated current		steel for rated current up to 40 A
		up to 630 A	above 630 A
BUT	Copper, aluminum copper	2.1.6
	Solid aluminum alloy
	Aluminum	2.1.7 1)	2.1.7 3) or 4) or 5)	2.1.7 2) or 3) or 4) or 5)
B	Copper, aluminum copper	2.1.6
	Solid aluminum alloy	2.1.7 4) or 5) and 3)	2.1.7* 4) or 5) and 3)	2.1.7 4) or 5) and 3)
	Aluminum	2.1.7 4) or 5) and 3)

* Contact connections of electrical devices of climatic modifications U, UHL of placement categories 1 and 2 are allowed to be made according to clause 2.1.6.

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

Table 5

Contact connection group	Conductor material	Standard item number depending on the type of core
		single-wire	stranded
BUT	Copper	direct connection
	Aluminum copper		-
	Aluminum		Direct connection* or 2.1.7 6) or 7)**
B	Copper	Direct connection* or 2.1.6***	2.1.6***
	Aluminum copper		-
	Aluminum	2.1.7 7) or 6) and 3)

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

** It is allowed to connect aluminum conductors 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 according to GOST 22002.5-76, GOST 22002.12-76, GOST 22002.13-76, GOST 23598-79 or by tinning the cores with tin-lead solders according to GOST 21931-76.

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

Examples of collapsible contact connections are given in Appendix 2.

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

2.1.9. Contact connections of hard aluminum alloy plates and the aluminum part of copper-aluminum plates with aluminum conductors (leads) must be made by welding or soldering, and the connections of hard aluminum alloy lugs 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. Collapsible contact connections of single-wire conductors of wires and cables with flat or pin terminals must be carried out:

- lived with a cross section of up to 16 mm 2 - after termination with lugs according to GOST 7386-80 or directly: by forming into a ring or without it, with protection in both cases from extrusion by shaped washers or other methods;
- core 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 bolt hole.

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

- lived with a cross section of up to 10 mm 2 - after termination with lugs according to 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 22002.11- 76, GOST 22002.14-76 or directly: by forming into a ring or without it with protection in both cases from extrusion by shaped washers, or by other means;
- lived with a cross section of 16 mm 2 or more - after termination with lugs according to 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, Rev. No. 1, 2).

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

2.1.13. In collapsible contact connections, fasteners of strength classes according to GOST 1759.4-87 and GOST 1759.5-87, indicated in Table. 6. Screws in contact connections are recommended to be used 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 leads) 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 specifications for specific types of electrical devices;
- for class 2 - 2;
- for class 3 - 6.

In contact connections of conductors with different electrical resistance, comparison is made with a contact piece with a higher electrical resistance.

2.2.2. The initial electrical resistance of contact connections of class 1 conductors with pin terminals should not exceed the values ​​\u200b\u200bspecified in Table. 7.

Table 7

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

2.2.3. The electrical resistance of contact joints (except for welded and soldered ones) that have passed the test 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 joints must remain unchanged. The need for the mandatory use of torque indicator keys should be indicated in the standards or specifications for specific types of electrical devices.

2.2.4. When the rated (continuous) current flows, the maximum allowable temperature contact connections of classes 1 and 2 should not exceed the values ​​\u200b\u200bspecified in table. 8. At the same time, the current loads of conductors are taken according to the "Electrical Installation Rules" approved by the State Energy Supervision Authority on 12.04.69, according to standards or specifications for specific types of electrical devices.

Table 8

Characteristics of the connected conductors	The highest allowable heating temperature, °С in units
	up to 1000 V	St. 1000 V
1. Conductors made of copper, aluminum copper, aluminum and its alloys without protective coatings of working surfaces	95	According to GOST 8024-90
2. Conductors made of copper, aluminum copper, aluminum and its alloys with protective coatings of working surfaces with base metals	110*
3. Conductors made of copper and its alloys without insulation or with insulation of classes B, F and H according to GOST 8865-87 with protective coating work surfaces with silver	135

* 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 the test results according to GOST 17441-84 and is indicated in the standards or specifications for specific types electrical devices.

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

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

2.2.5. (Deleted, Rev. No. 1).

2.2.6. After the through current mode, the contact connections should not have mechanical damage that prevents their further operation. The temperature of contact connections in the through current mode should not exceed 200 °C for connections of conductors made of aluminium-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 allowable through current of contact connections must not be less than the allowable through currents of specific types of electrical devices specified in the standards or specifications for these devices.

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

(Changed edition, Rev. No. 1).

2.3. Requirements for resistance to mechanical factors

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

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

2.3.2. Contact joints must withstand the effects of static axial tensile loads, causing stresses not less than:

- 90% of the tensile strength of the whole conductor - for contact connections of wires of a power line operating in tension;
- 30% of the tensile strength of the whole conductor - for non-separable 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 mm 2, it is not allowed to use a screw clamp, the screw end of which is rotated along the core.

2.3.1.-2.3.3. (Revised edition, Rev. No. 1).

2.3.4. Collapsible contact connections of conductors with leads, single-bolt contact connections that may be subjected to through short-circuit currents, as well as demountable contact connections that are subject to vibration or located in explosive rooms, must be protected from self-unscrewing by lock nuts, spring washers, Belleville springs or other means.

(Revised edition, Rev. No. 2).

2.4. Reliability Requirements

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

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 specifications for these electrical devices.

(Revised edition, Rev. 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 technical operation installations of consumers" and "Safety regulations for the operation of electrical installations of consumers", approved by the State Energy Supervision Authority on April 12, 1969.

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

(Introduced additionally, Rev. No. 3).

APPENDIX 1
Reference

NON-REMOVABLE CONTACT CONNECTIONS

a - welding or soldering; b - with a pin output by welding; c - welding through a transitional copper-aluminum plate; g - connection of cores of wires (cables) through a connecting sleeve by crimping; e - connection of the core of the wire (cable) with the cable lug by crimping (welding, soldering); e - connection of wire cores in oval connectors

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

APPENDIX 2
Reference

REMOVABLE CONTACT CONNECTIONS

a - with a locknut; b - with a spring washer; c - single-wire (multi-wire) core of a wire (cable) sec. up to 10 mm 2 with bending into a ring; g - single-wire (multi-wire) core of a wire (cable) sec. 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 Belleville spring; g - steel fasteners with protective metal coatings of working surfaces with a lock nut (spring washer); e - steel fasteners through an adapter 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 working surface; 13 - tire (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 the transitional copper-aluminum plate; e - single-wire (multi-wire) cable wire core sec. 10 mm 2 with bending into a ring.

1 pin copper or brass; 2 - nut made of copper or brass; 3 - tire (cable lug) made of copper, hard aluminum alloy or aluminum with a protective metal coating of working surfaces; 4 - steel nut; 5 - pin copper output; 6 - steel washer; 7 - aluminum bus (cable lug); 8 - pin brass output; 9 - pin steel output; 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 - typesetting clip; 2 - wire (cable); 3 - socket output; 4 - pin cable lug

REQUIREMENTS FOR THE PREPARATION OF WORKING SURFACES OF CONTACT DETAILS

1. Contact parts with two or more bolt holes 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 collapsible contact joints and non-separable contact joints with linear fittings immediately before assembly must be prepared:

- uncoated copper and aluminum-copper - cleaned.
When stripping aluminum-copper wires, the copper sheath should not be damaged;
- aluminum and aluminum alloys - cleaned and lubricated with neutral grease (Vaseline KVZ according to GOST 15975-70, TsIATIM-221 according to GOST 9433-80 or other lubricants with similar properties).
The recommended time between cleaning and lubrication is no more than 1 hour;
- work surfaces with protective metal coatings, - washed with an organic solvent.

(Revised edition, Rev. No. 3).

3. The working surfaces of copper contact parts connected by crimping must be cleaned, unless otherwise specified in the standards or 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 be pre-cleaned, degreased or pickled.

5. The location and size of the bolt holes in the contact details of the collapsible contact connections are recommended to be taken in accordance with GOST 21242-75.

By agreement with the consumer, it is allowed to make oval holes.

(Introduced additionally, Amendment No. 2).

TORQUES

Table 9

Thread diameter, mm	Torque, N m, for bolted connection
	with slotted head (screws)	with hexagon head
M3	0,5+0,1	-
M3.5	0.8±0.2
M4	1.2±0.2
M5	2.0±0.4	7.5±1.0
M6	2.5±0.5	10.5±1.0
M8	-	22.0±1.5
M10		30.0±1.5
M12		40.0±2.0
M16		60.0±3.0
M20		90.0±4.0
M24		130.0±5.0
M30		200.0±7.0
M36		240.0±10.0

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

(Revised edition, Rev. No. 3).

INFORMATION DATA

1. DESIGNED AND INTRODUCED by the Ministry assembly and special construction works the USSR

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

2. APPROVED AND INTRODUCED BY Decree State Committee USSR on product quality management and standards dated 03.02.82 No. 450

3. REPLACE GOST 10434-76

4. REFERENCE REGULATIONS

The designation of the NTD to which the link is given	Item number, listing, application
GOST 9.005-72
GOST 9.303-84	2.1.6; 2.1.7, listings 3, 8
GOST 12.1.004-91	2.5.2
GOST 12.2.007.0-75	2.5.1
GOST 1759.4-87	2.1.13
GOST 1759.5-87	2.1.13.
GOST 3057-90	2.1.7 item 2
GOST 7386-80	2.1.10; 2.l.11
GOST 7387-82	2.1.10; 2.1.11
GOST 8024-90	2.2.4
GOST 8865-87	2.2.4
GOST 9433-80	Appendix 3
GOST 9581-80	2.1.7, listing 4; 2.1.10; 2.1.10; 2.1.11
GOST 9688-82	2.1.11
GOST 13276-79	2.1.4; 2.1.7
GOST 14312-79	Introduction
GOST 15150-69	1.2; 2.1.8
GOST 15543-70	2.1.8
GOST 15963-79	2.1.8
GOST 15975-70	Appendix 3
GOST 16350-80	2.1.8
GOST 17412-72	2.1.8
GOST 17441-84	2.1.7 item 8; 2.2.3; 2.2.4
GOST 17516-72	2.3.1
GOST 18311-80	Introduction
GOST 19132-86	2.1.3
GOST 19357-81	2.1.7 item 4
GOST 21242-75	Appendix 3
GOST 21931-76	2.1.8
GOST 22002.1-82	2.1.11
GOST 22002.2-76 - GOST 22002.4-76	2.1.11
GOST 22002.5-76	2.1.8
GOST 22002.6-82	2.1.11
GOST 22002.7-76 - GOST 22002.11-76	2.1.11
GOST 22002.12-76	2.1.8
GOST 22002.13-76	2.1.8
GOST 22002.14-76	2.1.11
GOST 23598-79	2.1.7, listing 6, 7; 2.1.8
GOST 24753-81	2.1.2
GOST 25034-85	2.1.3
GOST 34-13-11438-89	2.1.7 item 4

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

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