PREFACE An experimental investigation of the shear buckling limit state was conducted on single web, cold-formed steel flexural members with web openings. The purpose of the investigation was to develop a better understanding of the behavior of web elements having a web opening, and to propose appropriate design recommendations based on the observed behavior. The present AlSI ASD and LRFD specifications do not contain design provisions for webs with openings, thus the findings of this study will aid in enhancing the shear design provisions. The test specimens, constructed from C-sections, were subjected to linearly varying shear resulting from the application of a uniform load. Test data from this investigation was combined with previous test data which was based on test specimens subjected to a constant shear. Three hole geometries, rectangular with comer fillets, circular, and diamond, were represented by the available test data. All openings were centered at mid-depth of the web. Based on the findings of this study, it was concluded that the slenderness ratio of the web element above or below the opening was dominant parameter influencing the shear behavior. It was also discovered that the distribution of the shear across the opening affected the shear capacity of the web. Based on the findings and conclusions obtained from the experimental investigations, a design expression was developed. The design expression recognizes the reduction in shear capacity of a web when an opening is present in the web. This report is based on a thesis presented to the faculty of the University of Missouri-Rolla in partial fulfillment of the requirements for the degree of Master of Science in Civil Engineering. The report was prepared for the AlSI Committee on Specifications for the Design of Cold-Formed Steel Structural Members. The investigation was sponsored by the American Iron and Steel Institute (AlSI). The technical guidance provided by the AlSI Stud Design; Perforated Elements Subcommittee is acknowledged. The Subcommittee members are: E. R. Estes, Jr. (Chairman), F. M. Bolio, R. E. Brown, C. R. Clauer, E. R. diGirolamo, L. Hernandez, W. Guiher, J. Klaiman, R. A. LaBoube, R. Madsen, J. P. Matsen, W. R. Midgley, T. H. Miller, K. T. Niu, T. B. Pekoz, C. W. Pinkham, G. S. Ralph, V. Sagan, R. J. Schrader, R. M. Schuster, T. W. Trestain, S. Walker, R. Zadeh. Thanks are also extended to D. F. Boring, R. B. Haws, H. Chen, K. C. Slaughter, and S. P.Bridgewater, AlSI staff. The cold-formed steel C-sections that were used in the test program were kindly donated by Dale/Incor Industries and Dietrich Industries. Their generosity is acknowledged. Thanks are also extended to J. J. Bradshaw, J. M. McCracken, and S. Gabel, staff of the Department of Civil Engineering, for their technical support
