Effect of circular holes on the web crippling capacity of cold-formed LiteSteel beams under Interior-Two-Flange load case

摘要

Lite Steel Beams (LSB) are innovative cold-formed formed steel sections, made of two rectangular hollow flanges with a web, and introduced in Australia claiming of flexural capacity enhancement. However, these sections are vulnerable to web crippling under concentrated loads and support reactions because of their slender webs when used as bearers and joists in floor systems. Limited research studies have been performed to investigate web crippling behaviour of these sections with fastened and unfastened supports under all four load cases, but without considering web hole effects. Recently few research studies indicated that the web crippling capacity of these sections reduced with the introduction of centred beneath and offset web holes under the End-Two-Flange load case, and hence it is critical. However, no investigations have been performed to explore the web hole effect of these sections under the Interior-Two-Flange load case. Therefore, this paper investigates the web crippling behaviour of LSB sections with three types of web holes: centred beneath, one offset, and two offset web holes, under Interior-Two-Flange (ITF) load case. The FE validations have been performed using four different experimental data sets from past research studies to generate accurate finite element models in ANSYS. In addition, a parametric study has been performed using validated FE models. A parametric study using 1126 FE models has proposed suitable capacity reduction equations for LSBs for centred beneath, one-side offset and both-side offset web holes. The results showed that the proposed equations provide accurate web crippling strength compared to design standards.