AISI-Specifications for the Design of Cold-Formed Steel Structural Members

Abstract

Light-gage steel roof, wall, and floor systems may be used to transfer in-plane shear forces from one part of a framed structure to another, leading to reduced loads in parts of the structure. Such behavior is particularly noticeable in buildings that have rigid shear walls and are subjected to lateral loads such as those arising from wind or earthquakes. The transfer of shear force through such diaphragms is dependent on the shear strength and is particularly sensitive to shear stiffness. The stiffness of the diaphragm must be considered in relationship to the stiffness of the structural frame. Diaphragm response to load is dependent on several variables including panel configuration, type and spacing of fasteners, panel length, cover width, material strength, supporting framework, the loading regime, and diaphragm size. Because of the large number of variables and parameters, it is impossible at this stage of the state of the art to predict diaphragm behavior from a purely analytical approach, therefore, test evidence must be drawn upon in large measure. It is the purpose of this investigation to provide such evidence, mostly for the lighter types of diaphragms used for roof decking and wall sheathing. This information is supplemented by earlier data published on heavier types of diaphragms. (See References I, 2, and 3.) In this investigation, in contrast to earlier work, pulsating and reversed loading have been used in addition to the common single loading to failure. It is also the purpose of this investigation to study several variables and their general influence on behavior in an attempt to establish: typical shear strength values, variation of shear deflection with load, maximum reliable strength under cyclic load conditions, and the influence of diaphragms in a structure. The study is limited to diaphragms made from open fluted and standard corrugated panels and does not consider cellular panel diaphragms nor diaphragms with filler material. Some 70 full scale diaphragms were tested as well as several smaller ones. The results are given in tabular form with typical data given graphically. It is shown that the shear strength is relatively independent of diaphragm length along the flutes when a regular fastener arrangement is used. However, for standard corrugated panels and some other shapes it is found that shear stiffness varies strongly with panel length even though shear strength per foot of diaphragm is essentially constant. Short numerical examples are presented to illustrate the use of data and to show diaphragm influence in simple buildings.

Department(s)

Civil, Architectural and Environmental Engineering

Research Center/Laboratory(s)

AISI - Specifications for the Design of Cold-Formed Steel Structural Members
Wei-Wen Yu Center for Cold-Formed Steel Structures

Sponsor(s)

American Iron and Steel Institute

Publisher

American Iron and Steel Institute

Publication Date

7-1-1967

Document Version

Final Version

Rights

© 1967 American Iron and Steel Institute, All rights reserved.

Document Type

Report - Technical

File Type

text

Language

English


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