Consider for a client, the design a footbridge for crossing a small stream on a purchased land. The bridge is intended for residential use only. The bridge consists of two identical trusses, spaced $3$ ft apart. For ease of fabrication, each truss is to be constructed of one size of welded steel pipe from that sourced in the table. All members are to have the same $3$ ft length. The $100$ lb forces represent the dead loads.

Design objective: You are to a$)$ specify the maximum safe live load for the bridge and b$)$ the diameter of pipe to be used. Establish a rationale for your design loads.

STEPS:

$1.$ First solve for the forces in each member by hand using only a model of the planar truss.