Question

Calculate bearing strength of 20mm diameter bolt of grade 4.6 for joining main plates of 10mm thick using cover plate of 8mm thick using single cover butt joint.

(a) 70.26 kN

(b) 109.82 kN

(c) 50.18 kN

(d) 29.56 kN

I have been asked this question in an online quiz.

Origin of the question is Bolted Connections topic in portion Bolted Connections of Design of Steel Structures

Answer 1

Correct answer is (c) 50.18 kN

Easy explanation: diameter of bolt = 16mm, diameter of hole =16+2 =18mm

e=1.5×18=27mm, p=2.5×16=40mm

e/3d0 = 27/(3×18) = 0.5, p/3d0 -0.25 = 40/(3×18) -0.25=0.49, fub /fb = 400/410=0.975

kb = minimum of (e/3d0, p/3d0 -0.25, fub /fb,1) = 0.49

bearing strength = 2.5kbdtfu/1.25 = 2.5×0.49x16x8x400x10-3/1.25 = 50.18 kN.