Which load combination category is used to model the response of a bridge to hydrologic events with reduced live load?

• A. Reduced live load for certain hydraulic events
• B. Earthquake loading with gamma_EQ
• C. Normal vehicular live load
• D. Slender steel member slip

Answer: (A)

In design practice, different load combination categories are used to represent how a bridge responds under specific scenarios. For hydrologic events like floods, traffic is largely absent, so the live load is reduced in the combination to reflect that reality. This approach lets engineers capture the dominant effects of water-related actions while avoiding overstressing the bridge with full vehicle loads. The category that specifically uses a reduced live load for hydraulic events is the one designed for this situation. It’s not about seismic loading, normal vehicular loading, or unrelated member behavior, which is why it best fits the question.