A Warren Truss is used to transfer the load from a bridge as shown in Fig. Q1(a). Two trusses stand on either side of the carriageway so that when a car weighing 15kN moves on the bridge, only half of the load is carried by each truss. (i) Determine the force in members AB, BC and BD when the car is at the middle of the bridge. [8 marks] B D 6@4m=24m Fig. Q1(a) 4m 15kN If BD has a cross-sectional area of 4000 mm and a Young's modulus of 200 GPa, what is the change in its length due to the applied force? [2 marks] (iii) On the basis of the change in length obtained for member BD, estimate the change in length for member AB if it also has the same cross-sectional area and Young's modulus as BD. [2 marks]