STUDY ON SHEAR RESISTANCE OF COLD-FORMED STEEL STUD. WALLS IN RESIDENTIAL STRUCTURE

Zhou Xuhong, Shi Yu, Zhou Tianhua, Liu Yongjian and Di Jin

Chang’an University, Xi’an, 710064, China
E-mail: zhouxuhong@126.com

Abstract

In this paper, tests and finite element analysis are used to study the shear resistance of cold-formed steel stud walls in low-rise residential structures. Firstly, the shear resistance of cold-formed steel stud walls under monotonic loading is tested. The test models, including walls with single-sided gypsum sheathing, walls with single-sided oriented strand board sheathing, and walls with gypsum sheathing on the back and oriented strand board on the face are made in full scale of engineering project. The test apparatus and test method and the failure process of specimens are introduced in detail. Then, the finite element analysis model of cold-formed steel stud walls considering geometric large deformation and materials nonlinear is presented to study their shear resistance. Walls were simulated as shell elements. The studs and tracks are simply connected. The screws connecting the sheathings to the frame are modeled by coupling methods. The solution method of equations is selected by ANSYS program automatically. Finite element analysis results in this paper are close to that of experiment. The results of test and finite element analysis show that sheathing materials influences the wall’s shear resistance more greatly. The strength of steel has a less influence on the shear resistance of walls. As the decrease of stud spacing, height of wall and screw spacing at the perimeter, the walls’ load ability increases obviously.

Keywords: cold-formed steel, assembled walls, shear resistance, experimental study, finite element analysis

1. Introduction

Assembled walls are the main load-bearing members of cold-formed steel residential buildings, and cold-formed steel stud walls are assembled by C-shaped steel studs (channel with lip flanges), U – shaped tracks (channel without lip flanges), gypsum board and oriented strand board (hereinafter OSB), which are connected by self-piercing or self-drilling screws(North American Steel Framing Alliance, 2000).

The shear resistance of cold-formed steel stud walls is associated with many factors, such as materials of studs and sheathing, screw spacing, height-width ration of wall, stud spacing and so on, so it is difficult to determine walls’ shear resistance by theoretical calculation, but mainly by test method (American Iron and Steel Institute, 1998; Serrette and Ogunfunmi, 1996; Serrette et al., 1997). However, tests cannot totally reflect the influence of all the factors on the shear resistance of walls. Finite element analysis certified correct by test is an effective method to study the shear resistance of cold-formed steel stud walls (Xia et al., 2004; Emad et al., 1999). Many scholars at home and abroad only have studied the shear resistance for a certain kind of cold-formed steel stud walls because of a series of complex factors listed above. In order to provide design guidelines’ tests and finite element analysis are presented to study the shear resistance of cold-formed steel stud walls in residential structures, and many factors influencing shear resistance are also analyzed in this paper.

423

M. Pandey et al. (eds), Advances in Engineering Structures, Mechanics & Construction, 423-435. © 2006 Springer. Printed in the Netherlands.

Table 1. Specimens of shear wall tests.

Denotation of wall specimens

Cold-formed steel member

Sheathing

Self-drilling

fastener

Fastener

interval

SSG

C89x44.5xl2xl.0 studs (lipped channel section with web height 89mm, flange width 44.5mm, lip width 12mm and thickness 1mm), Spaced 600mm on center U92x40x1.0 tracks (channel section with web height 91mm, flange width 40mm and thickness 1mm)

50mmx 1.0mm strap

gypsum sheathing on one side, with dimension 1.2mx3m and thickness 12 mm

ST4.2

150mm at the perimeter and

300mm in the middle field of board

SSO

OSB sheathing on one side, with dimension 1.2mx2.44m and thickness 9 mm

ST4.8

DSGO

gypsum sheathing with thickness 12 mm on one side and OSB sheathing with thickness 9 mm on the other side

ST4.2 and ST4.8