Civil Engineering Study 96-2
I. INTRODUCTION A. GENERAL An environmental concern regarding the use of wood being an appropriate construction material has become a contemporary issue. The depletion of forests, caused not only by the building construction industry, but also by natural disasters such as forest fires, has raised many questions about the conservation of the environment. Trees are being replanted in an effort to make up for the loss, but trees take many years to mature. Therefore, in an attempt to improve the environment and the feasibility of building construction, alternative materials for residential construction are being investigated. One material that is being researched extensively is cold-formed steel. Cold-formed steel has many advantages over other building materials. The foremost advantage is its recyclability, which is an environmentally attractive advantage. Other advantages of cold-formed steel are that it has a very high weight-to-strength ratio, construction is fast and easy, it can be mass produced with consistent cross-sectional properties, it is termite proof and rotproof, it is economic in transportation and handling, and it is noncombustible. Cold-formed steel has been preferred in light-industrial construction for many years because it is cost competitive and because of the aforementioned advantages. The use of cold-formed steel members in building construction began around the 1850's in the United States and Great Britain. Although cold-formed steel building construction began in the 1850's, cold-formed steel was not widely used until around 1940. Since 1946 the use and the development of thin-walled cold-formed steel construction in the United States have been accelerated by the printing of the Specification for the Design of Cold-Formed Steel Structural Members of the American Iron and Steel Institute (AISI). Each subsequent edition incorporates investigation results which have improved the completeness and surety of the specification. For example, based on a study by Hetrakul and Yu (1978), the 1980 edition underwent expansive refinement in the design of beam webs subjected to web crippling and the combination of bending and web crippling. However, the web crippling provisions and combined bending and web crippling provisions of the 1980 and subsequently revised editions of the Specification pertain only to flexural members without web openings. Since 1990, the University of Missouri-Rolla has conducted a comprehensive study of the behavior of web elements of flexural members with web openings subjected to loads causing bending, shear, and web crippling, and combinations thereof. The current AISI ASD Specification (1986) and AISI LRFD Specification (1991a) have no provisions for the possible degradation in strength for the various limit states of flexural members caused by the presence of web openings. The use of members with web openings spaced at intervals along the longitudinal axis of the section provides passages for conduits frequently used in building construction. The most significant reason for conducting this research investigation was the concern that the presence of web opening(s) would have a degrading effect on the web crippling behavior of flexural members. Therefore, the effect of a web opening must be defined, and if necessary, recognized by the AISI Specification provisions.
Civil, Architectural and Environmental Engineering
American Iron and Steel Institute
Wei-Wen Yu Center for Cold-Formed Steel Structures
Cold-Formed Steel Series
Missouri University of Science and Technology
© 1996 Missouri University of Science and Technology, All rights reserved.
Report - Technical
Uphoff, Craig; LaBoube, Roger A.; and Yu, Wei-wen, "Structural behavior of circular holes in web elements of cold-formed steel flexural members subjected to web crippling for end-one-flange loading" (1996). Center for Cold-Formed Steel Structures Library. 104.