CCFSS Library (1939 - present)

Alternative Title

Civil Engineering Study 72-1

Abstract

INTRODUCTION In steel design, the Specification for the Design of Cold-Formed Steel Structural Members l issued by the American Iron and Steel Institute has long been used for structural members cold-formed to shape from steel sheet or strip used for load-carrying purposes in buildings and other thin walled steel structures. Even though no thickness limitation was included in previous editions of the Specification, 2,3, the thickness of material used in the cold-formed steel construction was often limited to about 1/4 inch because the maximum thickness of steels used under all ASTM Specifications listed in Section 1.2 of the AISI Specification 2,3 is 0.2449 inch. During recent years, carbon steel sheets and plates in coils up to 1/2 inch thick have been successfully used for cold-formed steel structural members in building construction (schools, shopping centers, and apartments), industrial plants, farm equipment, railway cars, ship and barge construction, truck trailers, earthmoving equipment, highway median barriers, bridge construc-tion, conveyors, machinery frames, and others. 4,5 Cold-formed steel plate sections up to about 3/4 inch in thickness have been used for steel plate structures and transmission poles. Consequently, the scope of the AISI Specification was extended in 1968 to include the use of steel sheets, strip, and plates up to 1/2 inch in thickness provided that such steel conforms to the chemical and mechanical requirements of one of the listed material specifications. 1 In view of the fact that the AISI design provisions have been mainly based upon the research work conducted on specimens made from relatively thin steel sheets and strip in the thicknesses ranging from 0.03 to 0.19 inch,6 some building code organizations have limited the application of the AISI Specification only to steels under 1/4 inch thick, due to the fact that the validity of some design provisions presently included in the AISI Specification has not been demonstrated fully for cold-formed steel sections thicker than 1/4 inch in thickness. In order to study the structural behavior of steel members cold-formed from thick steel plates (up to about 1 inch in thickness) for the purpose of verification of some AISI design provisions, a research project entitled "Study of Cold-Formed Steel Structural Members Made of Thick Sheets and Plates" was initiated in September, 1971, at the University of Missouri-Rolla (UMR) under the sponsorship of the American Iron and Steel Institute. The research work reported herein was directed by Dr. Wei-Wen Yu, Professor of Civil Engineering, under the supervision of Dr. J. H. Senne, Chairman and Professor of the University of Missouri-Rolla Department of Civil Engineering. Research Assistants for the project were Victor A. S. Liu and William M. McKinney, graduate students of the Department of Civil Engineering. This report summarizes the research work on the study of thick, coldformed, steel sections conducted at the University of Missouri-Rolla during the academic year 1971-72 (September 1971 to December 1972). The objectives of the project and the planned program are described in Section 2. The findings obtained from a preliminary investigation are discussed in Section 3. Section 4 contains a discussion of the buckling strength and the effective design width of stiffened compression elements; emphasis is placed on the use of thick sheets and plates. The buckling strength of an initially curved unstiffened plate is discussed in Section S. Section 6 describes the effect of cold-work on mechanical properties of thick sheets and plates. Finally, a summary is presented in Section 7. Future work on the project for the academic year 1972-73 is outlined in Section 8. It should be noted that some of the findings reported herein have been discussed in the First and Second Progress Reports 7,8 and in a paper orally presented at the Research Session of the 1972 ASCE National Structural Engineering Meeting held in Cleveland, Ohio.9 This investigation was sponsored by American Iron and Steel Institute. The financial assistance given by the Institute and the technical guidance provided by the AISI Staff and the Institute's Task Group on Thicker Sheets and Plates are gratefully acknowledged. The AISI Staff responsible for this project included Dr. A.L. Johnson and Mr. D.J. Clark. The Task Group was constituted as follows: Mr. A.J. Oudheusden, Chairman, Messrs. H.R. Fink, T.J. Jones, R.W. Haussler, and D.S. Wolford, members.

Department(s)

Civil, Architectural and Environmental Engineering

Sponsor(s)

American Iron and Steel Institute

Research Center/Lab(s)

Wei-Wen Yu Center for Cold-Formed Steel Structures

Appears In

Structural Series

Publisher

Missouri University of Science and Technology

Publication Date

01 Jan 1972

Document Version

Final Version

Rights

© 1972 Missouri University of Science and Technology, All rights reserved.

Comments

First summary report

Document Type

Technical Report

File Type

text

Language(s)

English

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