The beam shown is simple span and is subjected to an unfacto

The beam shown is simple span and is subjected to an unfactored dead load PD = 2 k and live load PL = 3k at the middle of the beam. Dead load does not include beam weight. Select the beam depth to satisfy minimum height so that deflection does not need to be calculated. Select the beam width that is ½ the minimum height rounded up to the nearest inch. Reinforcement will be enclosed in #3 stirrups. Select the amount of reinforcing steel required (select from bars with diameters less than #8). Check minimum spacing requirements. Beam will be located inside a building (not exposed to weather). Concrete compressive strength, f’c = 4000 psi, and the steel is grade 60.

What is the required strength of the beam, M_u?

A) 65 kip-ft

B) 30 kip-ft

C) 44 kip-ft

D) 50 kip-ft

Solution

option D is correct. moment of resistance can be calculate using following

Load = 2+3 = 5 k.

Moment of resistance = 5*10 = 50 k-ft.