Structural performance of cold formed sections with single and multiple web openings. Part 1: Experimental investigation

In light gauge construction, the buildability of cold formed sections may be greatly improved by the provision of web openings, which allows easy integration of building services within the section depth. In order to assess the structural implication of web openings, to cold formed sections, the reduction in the web crippling and the load resistances of perforated sections were investigated. The effects of different opening sizes and shapes, and of different forms of stiffening around the openings, were also studied. A total of six test series with 57 web crippling and 41 beam tests were carried out on cold formed sections with single and multiple web openings; the results of the tests are presented in detail. It is found that, for perforated sections with practical opening sizes and shapes, the reduction to the web crippling and the load resistances is often not significant. In typical floor beams, the presence of single web openings in the sections may reduce the load resistances of the sections by only 5%-10%, provided that the web openings are located at specific positions. For sections with multiple web openings, the reduction to the load resistance of the sections is unlikely to exceed 15%. Consequently, it is demonstrated that the buildability of cold formed sections can be greatly enhanced with the provisions of web openings, without significant adverse effect in their structural performance. Simple design miles for perforated cold formed sections are also presented and they are supplementary to the normal design of the unperforated sections.