How many members are typically required for load path redundancy?

• A. 3+
• B. 2
• C. 1
• D. 4

Answer: (A)

Load path redundancy is about having multiple independent routes for the forces from the load on the structure to the supports, so the system can still carry the load if one member or path is compromised. In bridge practice, this means there should be at least three members forming alternate paths for transferring the load. With three or more paths, the loss of one member doesn’t leave the structure with a single path that could overload others or lead to progressive failure—the remaining paths can still carry the load. Two paths are not typically sufficient because losing one can overburden the other, and one path provides no redundancy at all. So, three or more is the standard expectation for meaningful load path redundancy.