Answer Happy

The end supports are assumed to be a pin at A and a roller at B. A vertical loading of 5 kN is to be supported within the middle 3 m of the span. This load can be applied in part to several joints on the top members within this region, or to a single joint at the middle of the span. The force of the wind and the weight of the members are neglected. Assume the maximum tensile force in each member cannot exceed 4.25 kN; and regardless of the length of the member, the maximum compressive force cannot exceed 3.5 kN. Design the most economical truss (Your design should include at least two different types of truss system eg: Pratt and Gambrell or Warren and Howe, etc.) that will support the loading. The members cost $3.50 per member and the gusset plates cost $8.00 each. Note: The 5 kN can be shared as: 1 + 3 + 1 or 2.5 +2.5 or 5 or any other combination within the 3 m span. The height of the bridge is arbitrary and would be dependent on your design.