JOINT STRENGTH OF COLD-FORMED STEEL TRUSSES

Abstract

This chapter outlines a brief summary of the current research. The main conclusions together with recommendations for future studies are also presented.

6.1Summary: The finite element method was used to analyze the proposed joints of cold­ formed steel trusses. An analytical model was presented by using the computer program COSMOS/M (1994) which considers both material and geometric non­ linearities. Force control combined with modified Newton Raphson technique as an iterative solution method were adopted to obtain the non-linear static equilibrium solution for the instability of the joint. The finite element program was used to: 1. Predict the strength capacity of cold-formed truss joints with different configurations. 2. Outline deformed shapes and contours of both displacements and stresses at the end of any loading step. Various problems have been introduced to verify the capability of the finite element model to accurately simulate experimental results presented by other researchers in the field of study. Moreover, an extensive research program was adopted to evaluate the strength capacity of cold-formed truss joints. Two groups of total 148 specimens were carefully chosen to represent a wide range of joint configurations by changing the geometric parameters of the joints. The first group of joints has a chord member composed of two unstiffened back-to-hack channels with three different thickness values (1.50 nun, 2.00 mm, and 2.50 mm). The effect of varying three parameters (eccentricity, gap distance, and chord pre-load) combined with the different thickness values of the chord member on the stren!¢1 capacity of joints was sty.died.