腐蚀后耐候钢梁栓焊节点的疲劳性能试验研究

Experimental study on fatigue behavior of corroded weathering steel bolt welded joints

裸露使用的耐候钢结构往往在受环境腐蚀的同时还可能承受疲劳荷载.为获得腐蚀后耐候钢梁栓焊节点的疲劳性能,对经过38天乙酸盐雾循环试验后的Q355NHD栓焊节点耐候钢梁试件的疲劳性能进行了试验研究.试验结果显示:腐蚀后的耐候钢梁栓焊节点处的疲劳裂纹均先发生在上翼缘(受压翼缘)过让孔两侧焊趾处,破坏裂纹往往发生在下翼缘(受拉翼缘)过让孔两侧焊趾处;对比未腐蚀普通钢梁栓焊节点的疲劳试验结果,发现耐候钢梁栓焊节点并未由于锈蚀而降低该处焊接的疲劳性能,即在工程疲劳设计中,免涂装耐候钢栓焊节点可以参考涂装普通钢梁栓焊节点进行疲劳设计.

Exposed weathering steel structures often endure environmental corrosion and fatigue loads. In order to obtain the fatigue behavior of welded joint of weathering steel beam after corrosion, a fatigue experiment of Q355NHD weathering steel bolt welded joints under acetate salt spray cycle test is conducted. The results show that the fatigue cracks began on the welding toes on both sides of upper web openings(compression flange), and the main cracks often occur at the welding toes on both sides of the lower web openings(tensioned flange). Compared with the fatigue test results of welded joint of common steel beam without corrosion, the fatigue performance of weathering steel bolt welded joints was not reduced under the accelerated corrosion experiment. Therefore, fatigue design of weathering steel bolted joints can be carried out by referring to welded joint of common steel beam.