Reliability Analysis of Steel Structures under Buckling Load in Second-order Theory

There are various theoretical methods and procedures to evaluate instability of members in steel frames, in which effects of overall buckling and also geometrical nonlinearity are considered. In the first part, aims are to compare these conventional methods and investigate the potential of the software to applying the effects in analysis. For this reason, obtained buckling loads of simple frames from conventional methods are compared with results of SAP2000. In order to consider the actual design issues and generalize the problem, buckling load of multi-storey steel frames with multiple openings (3 and 5 floors, 3 openings) is calculated. Also, uncertainties that exist in loading and modeling of structures such as geometrical imperfection, yield stress, and modulus of elasticity in buckling load of 2D framed steel structures have been studied. By performing these uncertainties to each reliability analysis procedures (first-order, second-order, and simulation methods of reliability), a reliability index from each procedure is determined. These values are studied and compared.