Find the allowable tensile force that the multiple bolted structural joint shown in figure (a) and (b) below can transmit. Also find the efficiency...

Find the allowable tensile force that the multiple bolted structural joint shown in figure (a) and (b) below can transmit. Also find the efficiency of the joint.

The plates are 250 mm wide and 20 mm (main plate) and 12 mm (cover plates) thick.

The bolts are 19 mm in diameter.

The allowable stresses are 140 MPa in tension, 70 MPa in shear and 340 MPa in bearing.