Strengthening Circular Holesin Web of Steel I-Beams

Abstract

This study aims to investigate the effect of making circular hole in web of existing steel I-beam on stiffness response and Ultimate Load Capacity (ULC) in addition how to strengthen this hole using steel ring stiffener. The experimental investigation has focused on testing four steel I-beam cases under concentrated point loads. The first one was tested steel I-beam with solid web as a reference (Control) case and the other three specimens were tested by making circular hole in web of steel I-beam without and with steel ring stiffeners. The experimental results demonstrate that the ULC and stiffness of steel I-beams significantly decrease with making a hole in web. Accordant of experimental work, it can be noted that behavior of steel I-beam with stiffening opening web using steel ring is satisfactory agreement with behavior of steel I-beam with solid web ( before cutting hole). To simulate the experimental cases, the nonlinear finite element model (NFEM) using ANSYS ver.11 software was adopted in this study. The numerical resultsof load-deflection response and distribution stress along the examined beams have been compared with experimental tests. In general, good agreement between the (NFEM) and experimental results has been obtained. The purposed of NFEM has been done for implementation a parametric study to investigate the effects of three parameters: size, location of opening web and thickness of stiffener steel ring. It was found that the ULC of steel I-beam with opening web dropped almost linearly with the increase in hole diameter of web at ratio of diameter hole to beam depth (D/H) greater than (0.5). Therefore, it can be recommended to usesteel ring stiffeners to strengthen steel I-beam with opening web which have diameter greater than half depth of this beam (0.5H).