折线隔板加强的箱形柱-翼缘削弱箱形梁与H形梁节点抗震性能试验研究

Experimental study on seismic performance of enlarged diaphragm-through joints of steel box column and steel box beam with reduced flanges and H-section beam

对5个折线隔板加强的隔板贯通式箱形柱-翼缘削弱箱形梁与H形梁异型节点和1个基本型隔板贯通式异型节点进行拟静力试验,研究折线隔板扩大头和箱形梁翼缘削弱型隔板贯通式箱形柱-箱形梁与H形梁异型节点的破坏模式、滞回性能、承载力、塑性转角、刚度退化和耗能能力等。试验结果表明:基本型异型节点在几何尺寸变化剧烈(应力高度集中)的箱形梁翼缘对接焊缝侧边开裂,节点的塑性转角约为0.014 rad,达不到FEMA要求的0.03 rad;折线隔板扩大头异型节点的塑性转角达到0.032~0.046 rad,承载力和耗能能力较基本型异型节点分别提高22.2%~64.3%和6.32~9.94倍;箱形梁翼缘与隔板对接焊缝断裂、隔板与柱壁板间焊缝剪切撕裂是折线隔板扩大头异型节点的主要破坏模式;试验的隔板贯通式箱形柱-箱形梁与H形梁异型节点显示,刚度较大的箱形梁翼缘对接焊缝均先于H形梁断裂。

Low-cycle reversed loading tests were performed on five linear enlarged diaphragm-through irregular joints of steel box column and steel box beam with reduced flanges and H-section steel beam and one conventional diaphragmthrough irregular joint. The failure mode,hysteresis loops,load bearing capacity,plastic rotation,rigidity degradation and energy dissipation of diaphragm-through irregular joints with linear enlarged junctures and reduced flanges of steel box beam were studied. Tests results show that the conventional irregular joint brittle fractures at butt weld between flanges of steel box beam and diaphragm-through rib where the geometry change sharply and the stress is highly concentrated. The plastic rotation of the conventional irregular joint is about 0. 014 rad and couldn't match the minimum requirement 0. 03 rad suggested in FEMA. The plastic rotation of irregular joints with linear enlarged diaphragm-through ribs and reduced box beam flanges reaches 0. 032-0. 046 rad,and the load bearing capacity and the energy dissipation capacity are increased by 22. 2%-64. 3% and 6. 32-9. 94 times compared with those of the conventional irregular joints,respectively. Fracture of butt weld between flanges of steel box beam and diaphragm ribs,shear failure of welding between diaphragm ribs and column walls are typical failure mode of irregular joints with linear enlarged diaphragm-through ribs and reduced box beam flanges. For the tested diaphragm-through irregular joints of steel box column and steel box beam and H-section steel beam,butt weld between flanges of steel box beam with large rotation rigidity and diaphragm-through ribs fractures earlier than that of H-section steel beam.