Check whether a welded CHS NB 80 (M) (t=4 mm, OD=88.9 mm, a=10.7 cm , r=3 cm), subjected to factored compression of 70 kN, and factored tension of 80 kN is safe or not. Take effective length =1.8 m about all the axes. The maximum permissible slenderness ratio is 250. Given, fu=450 MPa, fy=310 MPa. 15