Question

frame, whhere thhe steel. Take4 ksi ength factor, K is found to be 1.05. The RC comm is reinford Sestion A-Bending [Figures are not-to-scale (a) (4 pts] Determ ine the maximum P, the column can carry if it is loaded concentrically. Take b- 24 in. ine the maximum P and M, the column can carry if the outermost tensile layer of met is stretched toatensilestrain of000. Again,»-2Aǐn 0, determine the maximum M, the column can carry. Again, b-24 in. steel reinforce (C) 14 pts] If P is theumn adequately designed to carry P.-s10 k and M.-585 k-t. Explain Again. a pas ls the column adequately designed to carry P,-259 k and M.-85 k-ft. Esplain. Ag b 24 in. Bonus 2 pts] What is an adequate (or maximum) unsupported length (J) of the column to ha erness effect ignored. Take b-20 in. a)

Answer 1

Given that: The RC tied column shown Belongs a moment, resisting framw where the effective length factor k, is found to be 1.05 the RC column resistance with Am = 12 in_2 and fe = 4 k si a) b = 24 in By using column sale ratio lambda eaulto 0 lu/20 = 10 lu = 200 lu = 16.67 bt b) The maximum Po is given by Pu = 0.85 fc^prime (Ag - A_st) + f_y A_st = 0.85 times 4 times (20 times 20) - 10) + 60 times 10 Therefore Pu = 1936 ksi