摘要
为快速、准确测量悬索桥已紧固索夹螺杆的轴力,提出适用于该类螺杆轴力检测的超声纵波测量方法。该方法采用螺杆张拉设备将已紧固索夹螺杆张拉至设计荷载状态并测量出对应的螺杆夹持长度,根据螺杆轴力与回波声时的理论关系计算该螺杆的无应力回波声时,进而计算螺杆轴力。选用6根M52索夹螺杆并采用不同夹持长度进行MTS张拉试验,采用上述方法计算螺杆的无应力声时,并与实测值对比,结果表明:无应力回波声时计算值与实测值的最大偏差对应的轴力偏差为3.38%,两者均值偏差对应的轴力偏差为0.31%。实桥应用情况表明该法具有良好工程实用性,且在螺杆长度公差较小而要求全桥快速普检时,可采用该法得到小批量抽测螺杆的无应力回波声时均值作为无应力回波声时基准进行全桥螺杆轴力计算。
An ultrasonic longitudinal wave inspection method that can rapidly and accurately measure the axial forces of the already-tightened bolts in cable clamps of suspension bridge is proposed.During inspection,the already-tightened bolts are tensioned to design loads by the bolt tensioning device and the clamping lengths of bolts are measured.Then,based on the theoretical relationship between the bolt axial force and echo time,the echo time of the bolts in stress-free condition is calculated,upon which the bolt axial force is worked out.Six M52 bolts were selected for the MTS tensioning test in the contexts of diverse clamping lengths,the stress-free echo time of the bolts were calculated by the aforementioned method,and the calculated results were compared with the measured data.It was shown that the axial force deviation coinciding with the maximum deviation of the calculated and measured stress-free echo time was 3.38%,and the axial force deviation coinciding with the mean deviation of the calculated and measured stress-free echo time was 0.31%.The engineering practice proves that the method is quite applicable.If the length tolerance of bolts is small,and a fast general inspection of a suspension bridge is required,the proposed method can be employed to obtain the mean stress-free echo times of a small batch of sample bolts,which are subsequently used as benchmarks for the bolt axial force calculation of the full bridge.
作者
伊建军
高天
荆国强
王波
汪正兴
YI Jian-jun;GAO Tian;JING Guo-qiang;WANG Bo;WANG Zheng-xing(State Key Laboratory for Health and Safety of Bridge Structures,Wuhan 430034,China;China Railway Bridge Science Research Institute,Ltd. ,Wuhan 430034,China)
出处
《桥梁建设》
EI
CSCD
北大核心
2021年第6期39-44,共6页
Bridge Construction
基金
武汉市科技计划项目(2020010602011969)。
关键词
悬索桥
已紧固索夹螺杆
轴力
超声纵波测量
无应力回波声时
张拉试验
suspension bridge
already-tightened cable clamp bolt
axial force
ultrasonic longitudinal wave inspection
stree-free echo time
tensioning test
