Question

1. For the beams shown, find the location of the neutral axis relative to the compression face, c, and the strain in the steel, Et. Is the section tension controlled, compression controlled or in the transition zone? What is the nominal moment21 strength, Mn, the strength reduction factor, , and the design moment strength, Mn 20 3-48 a) fe 3000 psi ASTM A615 Gr60 reinforcement QUESTION2 Problem 1a: What is the nominal moment strength of the beam, Mn? O245 ft-k 223 ftk 207 ft-k 188 ft-k

Answer 1

answer is b

"Given Data: A615 Gv 60 f_y = 60,000 psi f'_c = 3000 psi AS = 3 = 3 times 0.79 = 2.37 in^2 [Area = 0.79 in^2] Equating compressive force to Tensile 0.85 f'_c b a = A_s f_y a = A_s f_y/0.85 times f'_c times b = 237 times 60,000/0.85 times 3000 times 24 = 2.32 in Location of the neutral axis c = a/