RESIDUAL STRESS DISTRIBUTION AND OVERALL STABILITY LOAD-CARRYING CAPACITIE OF H-SHAPED AND BOX SECTION COLUMNS WELDED BY Q345GJ STRUCTURAL STEEL PLATES UNDER AXIAL COMPRESSION
NIE Shi-dong;DAI Guo-xin;SHEN Le;YANG Bo;Key Laboratory of New Technology for Construction of Cities in Mountain Area (Chongqing University) Ministry of Education;School of Civil Engineering, Chongqing University;
Sectioning method was adopted to obtain the residual stress distributions on three column sections fabricated by Q345 GJ structural steel plates. The test results of residual stress distribution were simplified as multi line modes by using MATLAB and compared with national code modes. Nine welded H-shaped columns and three box section columns were axially loaded under compression to achieve the overall stability load-carrying capacities. Finite element models considering various distribution modes of residual stress, were employed via ABAQUS to simulate the experimental tests. The simulation results were then compared with the test results and calculation results from design code formula. Furthermore, parametric studies were performed to obtain the column curves. The experimental and analytical results show that the simplified multi line mode of residual stress distribution is more suitable than the one proposed by the national design code for both H-shaped and box section columns. Additionally, it is found that the residual stress distributions of one layer flange simplification and multi-layer flange simplification cause little distinction on the load-carrying capacities of H-shaped section columns around the weak sectional axis. Due to the apparent differences of residual stresses on section flange ends between the experimental results and the mode proposed by the national design code, the buckling resistances would decrease if the normalized slenderness ratio lies in the range of 0.4~1.1 in column curves.