The effect of flange restraint on web crippling strength of cold-formed steel Z- and I-sections

PREFACE When considering the web crippling strength of a cold-formed steel member, the current edition of the AISI Specification for the Design of Cold-Formed Steel Structural Members does not distinguish between the behavior of a member having its flanges attached to a support member, and a member not attached to its support. To enhance the industry and design professional\u27s understanding of web crippling, a study was initiated at the University of Missouri-Rolla to explore the influence of flange attachment. This research consisted of web crippling tests on identical specimens. The specimens were tested where either cross sections were attached to a support beam or were not attached to the support beam. This enabled direct comparison and evaluation of flange attachment. The results were compared with AISI design criteria and other prediction equations, and suggested design recommendations were developed. This report is based on the thesis presented to the Faculty of the Graduate School of the University of Missouri-Rolla in partial fulfillment of the requirements for the degree of Masters of Science in Civil Engineering. This investigation was sponsored by the American Iron and Steel Institute and the Metal Building Manufacturers Association. The technical guidance provided by the AISI Subcommittee on Flexural Members and the AISI Staff is gratefully acknowledged. Members of the AISI Subcommittee are: J. N. Nunnery (chairman), R. E. Albrecht, R. E. Brown, C. R. Clauer, D. S. Ellifritt, S. J. Errera, J. M. Fisher, T. V. Galambos, M. Golovin, G. J. Hancock, A. J. Harold, R. B. Heagler, D. L. Johnson, W. J. Kile, R. A. LaBoube, M. R. Loeske, R. Madsen, T. M. Murray, T. B. Pekoz, R. M. Schuster, P. A. Seaburg, T. Sputo, T. W. Trestain, and W. W. Yu. The AISI Staff include R. B. Haws and K. L. Slaughter. Thanks are also extended to W. L. Shoemaker of the Metal Building Manufacturers Association for his assistance