The structural behavior of cold-formed steel members with perforated elements

Analytical and experimental investigations have been conducted to study the influence of perforations on the structural behavior of cold-formed steel structural members. Since in many cases, the load-carrying capacity of cold-formed steel members depends on the buckling behavior of individual component elements, emphasis has been concentrated on the study of the instability and post-buckling strength of perforated elements. In this investigation, the buckling loads and post-buckling strength of stiffened and unstiffened compression elements having single circular and square holes have been studied analytically by using the finite element method. The effects of different holes on the buckling coefficient have been verified by the experimental data obtained from the testing of columns and beams with perforated flanges. The equations for determination of the effective width have been developed on the basis of the post-buckling strength of compression elements. An experimental investigation has been conducted to study the influence of holes on the shear buckling load of beam webs. The test data was compared with analytical results of other investigators. Better correlation was found between the test data and the analytical solution for the simple support condition. A load reduction equation was derived on the basis of the experimental study. The crippling strength of perforated webs were also investigated experimentally. In this investigation, twenty tests were conducted to cover a practical range of height-to-thickness ratios. Based on the results obtained from tests, load reduction factors were derived for steel members with circular and square perforated webs. The stability of perforated plates subjected to equal and opposite point loads were investigated. The trend of this analytic study was found in agreement with the experimental investigation. Design recommendations are developed for: perforated stiffened compression elements, perforated unstiffened compression elements, perforated shear webs, and crippling of perforated webs --Abstract, pages ii-iii

The structural behavior of cold-formed steel members with perforated elements

PREFACE This report was originally a dissertation presented to the Faculty of the Graduate School of the University of Missouri-Rolla in partial fulfillment of the requirements for the Degree of Doctor of Philosophy in Civil Engineering, for conferment in May 1972. The research project described within was sponsored by American Iron and Steel Institute through a Special Engineering Fellowship in the fiscal year 1970-71. The author wishes to thank Dr. Wei-Wen Yu, Associate Professor of Civil Engineering, University of Missouri-Rolla for his invaluable guidance in his joint capacity as the project director and as major advisor of my advisory committee. Thanks are due to Mr. L.A. Barron, Vice President - Engineering and Dr. A.L. Johnson, Senior Research Engineer of American Iron and Steel Institute for their advice and cooperation. Appreciation should also be expressed to the AISI committee, for which Dr. J.B. Scalzi was the chairman

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