Q345GJ钢(中)厚板H形及箱形柱残余应力与轴压稳定承载力分析

采用条形切割法对三种截面规格的Q345GJ钢焊接H形和箱形截面残余应力进行测试，通过MATLAB拟合得到其简化的多折线分布模式，并与规范所取残余应力分布模式对比。对9根焊接H形和3根焊接箱形（中）厚板足尺构件进行轴压试验，获得构件整体稳定承载力。引入实测残余应力，通过ABAQUS进行Q345GJ钢轴压柱有限元分析，并与试验结果、规范计算结果进行对比，同时开展参数化分析获得轴压构件稳定曲线。试验及分析结果表明:Q345GJ钢H形和箱形截面采用多折线简化分布模式更符合残余应力实测结果；Q345GJ钢（中）厚板H形截面翼缘采用不分层或考虑分层的残余应力简化模式，对于构件绕弱轴稳定承载力影响不大；Q345GJ钢H形截面实测残余应力分布模式在翼缘自由端处与规范有较大区别，构件在正则化长细比为0.4~1.1区段的稳定承载力有下降趋势。

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

Sectioning method was adopted to obtain the residual stress distributions on three column sections fabricated by Q345GJ 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.