Experimental Investigation of Cold-formed Steel Tubes Subjected to Web Crippling

A series of tests on cold-formed steel square and rectangular hollow sections subjected to web crippling is reported in this paper. The web crippling tests were conducted under two loading conditions of end-two-flange (ETF) and interior-two-flange (ITF), which are specified in the current North American Specification for cold-formed steel structures. The concentrated load was applied by means of bearing plates, which act across the full flange width of the specimen sections. Different bearing lengths were investigated. The test specimens were fabricated by cold-rolling from steel sheet with nominal yield strength of 345MPa. The measured web slenderness values of the tubes ranged from 15.5 to 46.0. The test strengths obtained from this study are compared with the design strengths obtained using the current North American Specification, Australia Standard, European Code and Chinese Code for cold-formed steel structures. It is shown that the design strengths predicted by the specifications are either unreliable or too conservative.