If Fck25 Nmm2 and fyk500 Nmm2 Problem2 A short braced column

If Fck-25 N/mm2 and fyk-500 N/mm2. Problem2: A short braced column is having fck-30N/mm2 and FY-500N/mm2 is required to support an ultimate axial load of 2100KN. And a moment of 65 KN-m Determine a suitable section for a column and the Design the steel required

Solution

Solution:-

P_u = 0.45 f_ck A_c + 0.75 f_y A_sc

2100 x 10³ = 0.45 x 30 x A_c + 0.75 x 500 x 1.4 /100 x A_c

A_c = 112000 mm²

Assume, Where area of steel = 1.4 % of area of concrete

Assume that column is square .

Then size of column(a) = (112000)

                                      = 335 mm

Area of column = 335 mm x 335 mm

Area of steel = (1.4/100) x112000

                       = 1568 mm²

Let 16 mm bars are used

Total number of bars = 1568/(/4x 16²)

                                      = 8