Code-check of bolts according to Indian standard
Shear capacity of bolts
The design strength of the bolt, , as governed shear strength is given by IS 800, Cl. 10.3.3:
where:
- – design shear capacity of a bolt
- – nominal shear capacity of a bolt
- – ultimate tensile strength of a bolt;
- – area for resisting shear; for shear plane intercepted by the threads, for the case where threads do not occur in shear plane
- – net tensile stress area of the bolt
- – cross-section area at the shank
- – partial safety factor for bolts – bearing type – IS 800, Table 5; editable in Code setup
When the grip length of bolts (equal to the total thickness of the connected plates) is higher than , the design shear capacity is reduced by a factor – IS 800, Cl. 10.3.3.2:
According to IS 800, Cl. 10.3.3.3, the design shear capacity of bolts carrying shear through a packing plate with the thickness mm shall be decreased by a factor:
Each shear plane is checked separately, and the worst result is shown.
Bearing capacity of bolts
The design bearing strength of a bolt on any plate, as governed by bearing is given by IS 800, Cl. 10.3.4:
where:
- – design bearing strength of a bolt
- – nominal bearing strength of a bolt
- – factor for joint geometry and material strength
- – end distance of the fastener along bearing direction
- – pitch distance of the fastener along bearing direction
- – ultimate tensile strength of the bolt
- – ultimate tensile strength of the plate
- – nominal diameter of the bolt
- – diameter of bolt hole
- – plate thickness
- – partial safety factor for bolts – bearing type – IS 800, Table 5; editable in Code setup
Bearing on each plate is checked separately and the worst result is shown.
The bearing resistance is reduced for oversized and slotted holes by a factor:
- 0.7 – for oversized and short slotted holes
- 0.5 – for long slotted holes
Sizes of oversized, short slotted, and long slotted holes are determined according to IS 800, Table 19.
Tension capacity of bolts
A bolt subjected to a factored tensile force is checked according to IS 800, Cl. 10.3.5:
where:
- – design tensile capacity of the bolt
- – nominal tensile capacity of the bolt
- – ultimate tensile strength of the bolt
- – yield strength of the bolt
- – net tensile stress area of the bolt
- – cross-section area at the shank
- – partial safety factor for bolts – bearing type – IS 800, Table 5; editable in Code setup
- – partial safety factor for resistance governed by yielding – IS 800, Table 5; editable in Code setup
Bolt subjected to combined shear and tension
A bolt required to resist both design shear force and design tensile force at the same time shall according to IS 800, Cl. 10.3.6 satisfy:
where:
- – factored shear force
- – design shear resistance of the bolt – IS 800, Cl. 10.3.2
- – design shear resistance
- – design bearing resistance
- – factored tensile force
- – design tensile capacity of the bolt