Define 'redundant load path' and provide an example in a typical multispan bridge.

• A. A single load path with no backups.
• B. An alternate means of carrying loads if a primary member fails; for example, adjacent girders or cross-bracing taking on load if a main girder fails.
• C. A theoretical concept with no real-world example.
• D. A method to transfer all loads to foundations during a collapse.

Answer: (B)

Redundant load path means there are alternate routes to carry loads if a primary member fails, so the structure can keep transferring forces to supports even after a component is compromised. In a typical multispan bridge, redundancy is created by designing adjacent girders to share the load and by using cross-bracing and diaphragms that connect elements so that if one main girder sustains damage, the neighboring girders and the deck can take on part of the load and continue delivering it to the supports. This setup helps prevent a rapid, progressive collapse caused by a single point of failure. By contrast, a single load path with no backups describes a non-redundant system, and viewing redundancy as merely a theoretical concept with no real-world example isn’t accurate since bridges routinely incorporate backup load paths.