Column's load calculation

Column's load calculation

1. 16 mm dia and 500W rod four nos used in 15” X 15” RCC tide column. Cylinder test result is 300 psi for 28 days. What is the allowable load?

Soln: Given that,

       A_g= 15 x 15 =225 in²

       A_sf  = 8 x 0.31 = 2.48 in²

       P_g = A_st/A_g = 2.48/ 225 = 0.11

F_y = 500W = 500 MPa

       = 500 x 145 = 7250 PSI

       = 72.5 Ksi                                                                                           

Column design

F_c = 300 Psi

       = 3 ksi

F_s = 0.4 x f_y = 0.4 x 72.5 = 29 ksi

Load P = 0.85 x A_g (0.25f_c x f_sP_g)

            = 0.85 x 225 ( 0.25 x m + 29 x 0.011)

            = 0.85 x 225 x 1.069

           = 204.45 kip