Project ForgeA steel bar of 10×50 mm is cantilevered with two M12 bolts (P and Q) to a rigid support to carry a static load of 4 kN. The bolts P and Q are 400 mm apart (centre to centre), each 100 mm from the nearer edge of the mounting plate, and the 4 kN load acts 1.7 m beyond the far edge of the plate (i.e. 2.0 m from the bolt-group centroid). The primary and secondary shear loads on bolt P, respectively, are
- 2 kN, 20 kN
- B20 kN, 2 kN
- C20 kN, 0 kN
- D0 kN, 20 kN
Explanation
Primary (direct) shear per bolt = W/n = 4000/2 = 2 kN. Eccentricity from the bolt-group centroid to the load e=2.0m; moment M=4000×2.0=8000 N·m. Each bolt is r=0.2m from the centroid, so Σr²=2(0.2²)=0.08 m². Secondary shear = Mr/Σr² = 8000×0.2/0.08 = 20,000 N = 20 kN.
Source: GATE ME 2008 (2008)
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