Which Strength load combination represents the simultaneous occurrence of normal vehicular use and a 90 km/h wind event with factors 1.35 and 0.40?

• A. Strength V
• B. Strength I
• C. Strength II
• D. Strength III

Answer: (A)

The key idea is that some load combinations are specifically meant to represent two actions happening at the same time — in this case, normal vehicular live load and a wind event. In LRFD practice, Strength load combinations are defined with particular sets of multipliers for different loads so engineers can check how the structure behaves under those concurrent actions.

For a 90 km/h wind event combined with typical traffic, the combination that uses a higher multiplier on the vehicular (live) load and a smaller multiplier on the wind component, exactly 1.35 and 0.40, is the one designated for this simultaneous scenario. That pairing is what Strength V represents, so it best matches the described condition. The other strength combinations are defined for different, non-concurrent or differently-weighted scenarios, so they don’t align with this specific case of live load together with wind at that speed.