Which load combination category is typically tailored to the material being used in the bridge structure?

• A. Service limit state load combinations
• B. Extreme-Event limit states
• C. Strength I Load Combination
• D. Fatigue and Fracture limit states

Answer: (C)

In bridge design, different load combinations serve different purposes, but the one used to verify that a member can actually carry the expected loads based on the material’s strength is the Strength I load combination. This category ties the resisting capacity of the member directly to the material properties (like yield strength for steel or compressive strength for concrete) and checks that capacity against the factored loads. Since the material’s strength governs the available resistance, this category is the one tailored to the material used in the structure. The other categories—serviceability checks under typical service conditions, extreme-event scenarios, and fatigue/ fracture considerations—focus on performance under different loading needs and do not align as directly with material-specific capacity in the same way.