When stairs spanning longitudinally are cast monolithically with their landings, the maximum bending moment per meter width is taken as___________________?
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Answer: B. wl²/8
Explanation
Longitudinal stairs cast monolithically with landings experience specific boundary restraint conditions. Engineering standards simplify these continuous slab moments to wl squared over eight. This formula accounts for both the self-weight and imposed loads acting downwards. Monolithic casting means stairs and landings are poured simultaneously as single units. Bending moment represents the internal reaction torque resisting external applied loads. The variable w denotes total load per unit length while l is span.
Staircases in multi-story residential buildings are frequently designed using this approach. Accurate moment calculation prevents excessive cracking and structural deflection in concrete. Safety coefficients are applied to guarantee long-term durability under heavy foot traffic. Option A uses wl squared over four which applies to cantilevered structural elements. Option C uses wl squared over ten which assumes different end restraint fixity. Option D uses wl squared over twelve which typically applies to fully fixed beams.
- Subject
- Engineering
- Category
- Civil Engineering
- Topic
- —
- Difficulty
- medium
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