A RELIABILITY STUDY ON A SYMMETRIC TWO-SPAN I - STEEL BEAM

Temple Nwofor

doi:10.3759/josem.v6i1.2320

Abstract

In this paper, a reliability study is carried out on a symmetric two-span I-Section steel beam using the First Order Reliability approach. The ultimate limit state of bending moment, shear stress and local buckling of web were the design criteria considered in the reliability index estimation. A Matlab code was developed based on the performance functions developed for the various failure modes and a Matlab optimizer, fmincon, was invoked in the reliability estimation. It was shown that the reliability indices decreased with increase in span of the beam and also decreased with increase in the load ratio. Also, increasing the beam span beyond 800 cm may jeopardize the safety of the beam for both the bending and shear failure modes. It was also found that the reliability indices decreased with increase in design strength for the web buckling mode. It was also found that the bending moment failure mode appeared to be more critical, followed by the shear stress failure mode and then the web buckling failure mode.