A cylindrical pressure vessel with a 1.5 m inside diameter is subjected to internal steam pressure of 1.5 MPa. It is made from steel plate by triple-riveted double-strap longitudinal butt joint with equal straps. The pitch of the rivets in the outer row is twice of the pitch of the rivets in the inner rows. The rivets are arranged in a zigzag pattern. The efficiency of the riveted joint should be at least 80%. The permissible stresses for the plate and rivets in tension, shear and compression are 80, 60 and 120 N/mm² respectively. Assume that the rivet in double shear is 1.875 times stronger than in single shear. Design the joint and calculate:
(i) thickness of the plate;
(ii) diameter of rivets;
(iii) pitch of rivets;
(iv) distance between the rows of rivets;
(v) margin;
(vi) thickness of the straps; and
(vii) efficiency of the joint.
Draw a neat sketch of the riveted joint showing calculated values of dimensions.