A pressure vessel of the boiler consists of cylindrical shell of 0.8 m inner diameter. It is subjected to internal steam pressure of 2 MPa. Triple-riveted double strap longitudinal butt joint is used to make the shell. The straps are of unequal width. The pitch of the rivets in outer row is twice of the pitch of rivets in middle and inner rows. A zig-zag pattern is used for arrangement of rivets. The efficiency of the joint should be at least 80%. The corrosion allowance is 2 mm. The permissible stresses for rivets and sheli in tension, shear and compression are 80, 60 and 120 N/mm2 respectively. Calculate: (i) thickness of the shell (ii) diameter of the rivets;  (ii), pitch of the rivets in outer row (iv) distance between outer and middle (v) distance between middle amd inner rows; (vi) thickness of inner strap; (vii) thickness of outer strap; and (vii) efficiency of the joint [(i) 14.5 or 15 mm (ii) 23.24 or 24 mm (ii) 130 mm (iv) 53.6 or 55 mm (v) 37.53 or 40 mm (vi) 11.25 or 12 mm (vi) 9.38 , or 10 mm(viii) 81.54%)]