The figure shows a cast-iron bearing block that is to be bolted to a steel ceiling joist and is to support a gravity load of 18 kN. Bolts used are M24 ISO 8.8 with coarse threads and with 4.6-mm-thick...

to support a gravity load of 18 kN. Bolts used are M24 ISO 8.8 with coarse threads and with

4.6-mm-thick steel washers under the bolt head and nut. The joist flanges are 20 mm in thickness, and the dimension
A, shown in the figure, is 20 mm. The modulus of elasticity of the

bearing block is 135 GPa.

(a) Find the wrench torque required if the fasteners are lubricated during assembly and the joint

is to be permanent.

(b) Determine the factors of safety guarding against yielding, overload, and joint separation.