Secondary Collapse refers to which scenario?

• A. A collapse that occurs during the initial event.
• B. A collapse that occurs after the initial collapse (e.g., aftershocks, weather, movement).
• C. A collapse that occurs only in trenches.
• D. A collapse that happens due to interior piping.

Answer: (B)

Secondary collapse means the structure can fail again after the first collapse has already occurred, as ongoing conditions or loads cause additional portions to give way. This includes factors like aftershocks, weather effects, or movement of the damaged structure that destabilize other sections. That’s why the scenario described is a collapse occurring after the initial collapse, such as due to aftershocks, weather, or movement. It isn’t the initial event, it isn’t limited to trenches, and it isn’t specifically caused by interior piping.