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Shear and Tension Capacity of stainless steel bolts

Introduction

(NB The information given on this page was in accord with the approach originally presented in SCI publication P291, ‘Structural Design of Stainless Steel’, 2001, but a new procedure is recommended in the latest version of the design manual, see , and this should be followed for structural applications. The approach given here is more conservative. )

The shear capacity of a bolt, Psb, should be taken as:
Psb = psb As
where:
psb is the shear strength of bolt = 0.48 Usb or <= 0.69 Y0.2b (i.e. use whichever is lower)
As is the shear area, usually taken as the tensile stress area, unless it can be guaranteed that the threaded portion will be excluded from the shear plane, in which case it can be taken as the unthreaded shank area.

The tension capacity Pnom is given by Pnom = 0.8 ptb At where:

ptb= 0.7 Usb (U is the tensile strength) or <= Y0.2b (i.e. use whichever is lower)

The 0.8 factor is a simple  allowance for prying forces, which need not be calculated when using this approach, see and AD 354.

The following tables gives the shear strengths, (in N/mm2), of stainless steel bolts and shear capacities, (in kN), for bolts of diameter M10 to M24.

Shear and tensile strengths of bolts in clearance holes

Bolt grade (BS EN ISO 3506) Property class (BS EN ISO 3506) Shear strength psb (N/mm2) Tensile strength ptb (N/mm2)
A1, A2 and A4 50 145 210
70 311 450
80 384 560

Shear and tension capacities of bolts in clearance holes

Bolt size Property class

(BS EN ISO 3506)

Shear capacity (1)

Psb (kN)

Tension Capacity

Pnom (kN)

M10 50  8.4 9.8
70 18.0 20.9
80 22.3 26.0
M12 50 12.2 14.2
70 26.2 30.3
80 32.4 37.8
M14 50 16.7 19.3
70 35.8 41.4
80 44.2 51.5
M16 50 22.7 26.4
70 48.7 56.5
80 60.3 70.3
M20 50 35.5 41.2
70 76.1 88.2
80 94.1 109.8
M24 50 51.1 59.3
70 109.6 127.1
80 135.6 158.1
M27 50 66.4 77.1
70 142.5 165.3
80 176.3 205.6
M30 50 81.2 94.2
70 174.2 202.0
80 215.5 251.3
M33 50 100.5 116.6
70 215.5 249.9
80 266.6 310.8
M36 50 118.3 137.2
70 253.7 294.2
80 313.8 365.9
M39 50 141.3 164.0
70 303.0 351.4
80 374.9 437.1
(1) The shear area As has been taken as the tensile stress area of the bolt, At

Note: These values of shear capacity should be used in conjunction with FACTORED loads. The relevant load factors can be obtained from BS 5950 The structural use of steelwork in building, Part 1 Code of practice for design – rolled and welded sections.

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