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In roof systems, a high strength steel profiled sheeting fastened to high strength steel cold-formed purlins of a lipped C- or Z-section is commonly used throughout the world. The design of such systems is performed according to the provisions of the limit states Australia/New Zealand Standard for Cold-Formed Steel Structures in Australia and the North American Specification for the Design of Cold-Formed Steel Structural Members in the United States. In both standards, which include the newly developed direct strength method of design (DSM), the method presented is limited to pure compression and pure bending. The situations of pure shear and combined bending and shear as occurs in a continuous purlin system are not considered. In order to extend the DSM to purlin systems, three different test series on high strength cold-formed C-section purlins have been performed at the University of Sydney. The test series include predominantly shear, combined bending and shear, and bending only test series. Two different section depths and three different thicknesses of the lipped channel section were tested in this study. Further, tests with and without torsion/distortion restraint straps screwed on the top flanges adjacent to the loading points were also considered. This paper summarizes the test results and formulas developed from the effective width method and the DSM. Proposals for design are included in this paper. Comparisons with the Australian Steel Structures Standard are also included to take account of the tension field action. [ABSTRACT FROM AUTHOR]

A series of tests on cold-formed high-strength stainless steel square and rectangular hollow sections subjected to web crippling is presented in this paper. The types of stainless steel investigated in this study were high strength austenitic and duplex material. The measured web slenderness value of the hollow sections ranged from 16.5 to 49.7. The tests were carried out under four loading conditions considered in the American Specification and Australian/New Zealand Standard for cold-formed stainless steel structures, namely end-one-flange, interior-one-flange, end-two-flange, and interior-two-flange loading conditions. The web crippling test strengths were compared with the design strengths obtained using the American, Australian/New Zealand, and European Specifications for stainless steel structures. In addition, the North American Specification for cold-formed carbon steel structural members was also used to predict the web crippling strengths and compared with the test results. It is shown that the design strengths predicted by the specifications are either unconservative or very conservative. Hence, a unified web crippling equation with new coefficients for cold-formed high strength stainless steel square and rectangular hollow sections is proposed in this paper. It is shown that the proposed web crippling equation is safe and reliable. [ABSTRACT FROM AUTHOR]

An experimental investigation of cold-formed stainless steel hollow sections subjected to web crippling is presented in this paper. Tests were conducted on square and rectangular hollow sections of austenitic stainless steel type 304. Tensile and compression coupon tests were performed to obtain the longitudinal tension and transverse compression material properties. The web crippling tests were conducted under two loading conditions for end-two-flange and interior-two-flange specified in the current American Specification and Australian/New Zealand Standard for cold-formed stainless steel structures. The test strengths obtained from this study and the test strengths of stainless steel lipped channel sections under end-one-flange and interior-one-flange loading conditions conducted by other researchers are compared with the design strengths obtained using the current American Specification, Australian/New Zealand Standard and European Code for cold-formed stainless steel structures. In addition, the test strengths are also compared with the design strengths obtained using the unified web crippling equation as specified in the North American Specification for cold-formed carbon steel structural members. A unified web crippling equation for cold-formed stainless steel sections with single web is proposed in this paper. [ABSTRACT FROM AUTHOR]