(Solved): 2. Figure Q2 shows a simply-supported pin-jointed truss carrying a crane rail on its top chord BH. ...

2. Figure Q2 shows a simply-supported pin-jointed truss carrying a crane rail on its top chord BH. The truss is provided with a support system comprising simply supported beams so that all loads applied to the crane rail will be transmitted to the truss only at the joints of the top chord. (a) Draw the influence lines for the following load effects if a vertical unit load moves from B to H:- (1) vertical reaction R, at support a; and (ii) force Fcd in the inclined member cD. (12 marks) (b) If a loading system comprising a uniformly distributed load of 30 kN/m (which can be of any length) and a pair of point loads of 100 kN and 60 kN at 4 m apart moves on the crane rail, show how the loading should be arranged to produce critical live load effects in (a) above and determine the magnitudes. State clearly the sign conventions adopted. (8 marks) Loading applied on top chord only E F G H B ? D W 8m A I b ? d e f g h Member D 8m a 8 panels @ 6m = 48m Figure Q2