Textbook Problem

A plane truss is subjected to loads 2P and P at joints B and C, respectively, as shown in the figure part a. The truss bars are made of two L 102 X 76 X 6.4 steel angles (see Table F-5(b): cross-sectional area or the two angles, A = 2180 mm², and figure part b) having an ultimate stress in tension equal to 390 MPa. The angles are connected to a 12-mm-thick gusset plate at C(figure part c) with 16-mm diameter rivets; assume each rivet transfers an equal share of the member force to the gusset plate. The ultimate stresses in shear and bearing for the rivet steel are 190 MPa and 550 MPa, respectively. Determine the allowable load P_allowif a safety factor of 2.5 is desired with respect to the ultimate load that can be carried. Consider tension in the bars, shear in the rivets, bearing between the rivets and gusset plate. Disregard friction between the plates the bars, and also bearing between the rivets and the and the weight of the truss itself.