STATIC STRENGTH OF SQUARE TUBULAR Y-JOINTS WITH REINFORCED CHORD UNDER AXIAL COMPRESSION

Chord reinforcement is an available alternative to improve the static strength of the welded square tubular joints. Four full-scaled square tubular Y-joints are studied experimentally to investigate the effect of local chord reinforcement on their static strength. From experimental results, it is found that the static strength of a square tubular Y-joint can be improved greatly by increasing the chord thickness locally near the brace/ chord intersection. The failure mode of an un-reinforced Y-joint can be changed from local yielding around the brace/ chord intersection to flexural yielding of the chord member when the local chord thickness is increased to a critical value. In addition, finite element (FE) models for analyzing the static behavior of square tubular Y-joints are also presented, and the accuracy and reliability of these models have been evaluated by comparing the FE results with experimental results. Finally, influence of some parameters (Lc/d, beta, gamma and T-c/t(0)) on the static strength of square tubular Y-joints with local chord reinforcement is studied, and a parametric equation for predicting the static strength of square tubular Y-joints with local chord reinforcement under axial compression is presented. The accuracy of the presented equation is verified through error analysis.