在役桥梁高强螺栓相控阵超声检测工艺探讨

Discussion about phased array ultrasonic testing technology for high-strength bolts of in-service bridges

高强螺栓广泛应用在钢结构桥梁中的连接上,在役使用过程中承受复杂的应力、温度变化等的作用,容易引起螺栓断裂或失效,其失效断裂是导致结构完整性破坏的重要原因,因而其安全性受到越来越多的重视。如何在不拆卸螺栓的前提下,检测出螺栓的疲劳裂纹始终是个难题。对在役桥梁钢塔高强螺栓进行了应力分析,确定了主要高应力水平位置,通过仿真模拟技术,分别研究了相控阵超声环阵探头线扫和相控阵超声线阵探头扇扫检测桥梁螺栓的关键技术,制定了在役桥梁高强螺栓检测工艺和方案,使用专用试块进行了灵敏度和螺栓全体积覆盖确认,并在实验室、现场进行了测试和验证。结合理论分析,实现对在役桥梁螺栓检测的全覆盖,解决了在役桥梁高强螺栓检测难题。

High strength bolts are widely used in the connection of steel structure bridges.They usually need to withstand complex stress and the influence of temperature variation in service process,which can cause fracture or failure of bolts.The failure fracture is an important factor to cause the structural integrity failure,so the safety is paid more and more attention.How to detect fatigue cracks in bolts without dismantling them is always a challenge.In this study,the stress analysis on the high-strength bolts of in-service bridge steel towers was conducted.The main positions with high stress level were identified.Through simulation technology,the key technologies of phased array ultrasonic ring array probe line scanning and phased array ultrasonic line array probe fan scanning for detecting bridge bolts were studied.The inspection process and plan for high-strength bolts of in-service bridges were established.The sensitivity and coverage were confirmed using dedicated test blocks,which were tested and verified in the laboratory and the field.By combining with theoretical analysis,the full coverage of in-service bridge bolt testing had been achieved,solving the problem of high-strength bolt testing for in-service bridges.