高墩大跨连续刚构桥的荷载试验研究

Research on load test of long-span continuous rigid frame bridge with high piers

为探明某高墩大跨连续刚构桥在正常运营状态及最不利受力状态下的动静态荷载特性,基于成桥荷载试验方法,开展不同车辆位置、车速等条件下大跨连续刚构桥动静荷载现场试验。试验主要包括正载及偏载两种情况,静荷载试验测试了这两种情况下的主梁应变与挠度,动荷载试验分别在20、30、40 km/h车速下,通过无障碍行车试验和刹车试验,测试了桥梁的冲击系数、自振频率及动应变。在采集处理完现场数据后,将其与有限元软件的理论计算结果进行对比分析。研究结果表明:该连续刚构桥在正载及偏载两个工况下,挠度和应变实测值均小于理论计算值,相对残余应变最大值为18.8%,相对残余挠度最大值为11.71%,均不超过20%;在动载试验中,主桥一、二、三阶竖向实测振动频率均大于理论计算值;该连续刚构桥承载能力满足要求。

To investigate the dynamic and static load characteristics of a high-pier long-span continuous rigid frame bridge under normal operational conditions and the most unfavorable stress states,dynamic and static load field tests were conducted based on the bridge load test method.These tests considered various vehicle positions and speeds.The testing encompassed two primary scenarios:positive load and partial load.In the static load tests,the strain and deflection of the main beam under these two conditions were measured.Dynamic load tests assessed the bridge′s impact coefficient,natural frequency,and dynamic strain through barrier-free driving and braking tests at speeds of 20,30,and 40 km/h.Upon collecting and processing the field data,a comparative analysis was performed against theoretical calculations obtained from finite element software.The results indicate that the measured deflection and strain values of the continuous rigid frame bridge are lower than the theoretical values under both positive and partial load conditions.The maximum relative residual strain is found to be 18.8%,and the maximum relative residual deflection is 11.71%,both of which are below 20%.Furthermore,the measured vertical vibration frequencies of the first,second,and third mode of the main bridge exceed the theoretical values.Overall,the bearing capacity of the continuous rigid frame bridge meets the required standards.