Failure of RHS Steel Columns and Local Buckling at Elevated Temperatures

Abstract

This study investigates the behavior of RHS(Rounded Hollow Square) steel columns in fire conditions and represents the functional effect of temperature on yield strength and modulus of elasticity. A nonlinear finite element modal using Ansys(9) has been developed to investigate the effect of fire on the buckling of RHS and mode shape. With an increase of temperature, strength of steel and stiffness of columns decrease leading to buckling at an even much lower of external loading than at no temperature effect. An extensive parametric study on columns with RHS are discussed to study of their behavior under fire conditions. The results are used to study the different types of failure mode occur due to increasing of temperature and studying of  the influence of slenderness ratio due to fire. In this study the local buckling coefficient for stiffened elements, is equal to 4.4 in 900^oC and 5.97 in 0^oC than compare with the values of some searchers is good .