What wind speed threshold defines Strength III load combinations?

• A. 70 km/h
• B. 60 km/h
• C. 120 km/h
• D. 90 km/h

Answer: (D)

Wind design uses different load combinations depending on how severe the wind action is. The code sets a specific wind speed threshold that tells you when to switch to a stronger set of combinations, which include higher wind effects together with dead and live loads. The value 90 km/h is that threshold for Strength III in this context, meaning once the wind speed reaches or exceeds 90 km/h, you evaluate the structure with the Strength III combinations to account for more demanding wind actions and their interaction with other loads. The other numbers correspond to thresholds for other strength levels, not the point at which Strength III is triggered, so they don’t fit as the defining limit. In short, 90 km/h is the wind speed that activates the Strength III load combinations.