基于有限测点的悬索桥位移场获取与安全评估

Displacement Field Acquisition and Safety Assessment of Suspension Bridges Based on Limited Measurement Points

为对桥梁进行位移监测与安全评估,提出了基于有限点监测的桥梁位移获取技术和桥梁安全评估技术。首先通过实际的监测方案对有限点进行监测,反算荷载加载到有限元模型,实现全桥的实时有限元分析。接着将位移实测值经过处理后作为"实测值",分析得到各个截面位移所对应的"包络区间",最后将位移指标的包络区间是否能包络其对应的实测值作为评估的判断条件。综合分析表明:将六个监测点信息都用于反算,得到的监测点值与实测值基本符合,两者差值在5%以内,后续可采用临时监测信息来检验反算荷载的准确性;该大桥最大容许挠度为L/300=380×1 000/300=1 266.7 mm。从提取的历史数据中最大挠度为:1 029.3 mm,在容许挠度范围内,由此可见大桥运营状况良好。采用基于有限点监测的桥梁位移获取技术和桥梁安全评估技术,可以实现对桥梁进行位移监测和安全评估的要求。

To conduct the displacement monitoring and security evaluation of the bridge,the technology of the displacement acquisition and the security evaluation were proposed based on the finite points monitoring were presented. Firstly,the finite points were monitored by the actual monitoring scheme,and the inversely calculated loads were put on the finite element model. The purpose was to realize the real-time finite element analysis of the whole bridge. Then,the measured values of the displacement were processed as the ＂ actual value ＂,and the corresponding ＂ envelope interval＂ of each section was analyzed. Ultimately,whether the actual values were located in the envelope interval of the displacement index could be regarded as the judgment condition of the evaluation.The analysis comprehensively showed that the information of the six monitoring points were used for inverse calculation. And the calculated values were in agreement with the measured values,the difference of which were within 5%. Subsequently,the interim monitoring information were used to test the accuracy of the inversely calculated loads. The maximum allowable disturbance degree of the bridge was L/300 = 380 × 1 000/300 = 1 266. 7mm. Meanwhile,the maximum disturbance degree of the extracted historical data was 1 029. 3 mm and in the range of allowable value. That showed that the bridge was in a good condition. In summary, the technology of displacement acquisition and bridge safety assessment based on the finite points monitoring,could meet the requirement of displacement monitoring and security evaluation.