Numerical Study on Upgrade of Steel I-Beams and Columns with Rectangular Web Openings

Abstract

This study investigated numerically the effect of small and large rectangular web openings in unstrengthened and strengthened steel I-beams and columns. With the use of a numerical model, 25 simply supported steel I-beams were subjected to a four-point bending test. In addition, 25 steel I-columns were tested numerically under axial compressive load. All steel I-beams and columns were compared with solid reference specimens without web openings (control specimen), where all specimens have the same 400 mm depth and 177 mm width steel section dimensions. Twelve of the 25 steel I-beams and columns with openings were strengthened with steel plates, and all had different web openings that were symmetrically located near the support areas. The performance of all steel I-beams and columns was compared before and after a strengthening procedure. The selected opening depths ranged from 40 to 280 mm. Aspect ratios of opening length to opening depth of 1.0, 2.0, and 3.0 were chosen. ABAQUS software was used to perform numerical analysis on I-sections (beams and columns) that were either unstrengthened or strengthened. All specimens were analyzed in terms of their load-displacement characteristics and failure modes. Finite element analysis showed that those beams and columns with small web openings have a slight decrease in strength and stiffness, which is considered to be within acceptable limits unlike solid steel beams and columns (control specimen). I-section beams and columns that have been strengthened have significant effects on increasing the load-displacement characteristics.