节点板高强螺栓预紧力松弛试验研究

EXPERIMENTAL RESEARCH ON PRE-TIGHTENING FORCE RELAXATION OF HIGH-STRENGTH BOLT IN JOINT PLATE

为了控制节点板高强螺栓施拧过程中的预紧力松弛,制定合理的节点板高强螺栓施拧顺序和接合面间隙控制要求,通过钢桁架节点足尺模型试验,监测高强螺栓施拧后预紧力变化规律,分析施拧顺序和接合面间隙对高强螺栓预紧力的影响。试验结果表明:高强螺栓施拧后4 h内预紧力松弛明显,施工检测宜在施拧4 h后进行;采用由内向外交叉竖向施拧可以降低高强螺栓预紧力损失,为较为合理的施拧顺序;接合面间隙大于1.0 mm时,高强螺栓预紧力损失明显增加,应采用适当处理方法减小接合面间隙,降低高强螺栓预紧力松弛水平。

In order to control the pre-tightening force relaxation of high-strength bolt in joint plate during screwing period and establish reasonable control requirements for screwing sequence and joint plate gap,a full scale model of steel truss joint was constructed for testing the pre-tightening force relaxation of high-strength bolts.The change rule of pre-tightening force relaxation with time was monitored,and the influence of screwing sequence and joint plate gap were investigated.The test results showed that the pre-tightening force relaxation of high-strength bolt was obvious within 4 hours after screwing,and the inspection should be completed after 4 hours.The vertical crossing sequence from inside to outside for high-strength bolt screwing was the most reasonable screwing sequence and could reduce the pre-tightening force loss of high-strength bolts.The pre-tightening force relaxation of high-strength bolts increased obviously when the gap was larger than 1.0 mm.Appropriate treatment methods should be adopted to reduce the gap between joint plates and the pre-tightening force loss of high-strength bolts.