Analysis And Monitoring For The Calculation Of Mechanical Properties Of High Pier And Long Span Continuous Rigid Frame Bridge

With the rapid development of China’s western construction, bridge constructiontechnologies develop fast and new technologies are applied continuously. The span ofcontinuous rigid frame bridge continue to increase, mass of upper structure continuesto become lighter, the overall flexibility of the structure increases, make themechanical of large span continuous rigid frame bridge become more complex. On theone hand, the bridge is effected by internal and external factors during construction,construction process is complex and difficult to control, which easily cause safetyincidents; on the other hand, in the using process, bridge structure is affected byexternal environment, which makes beam appear large deflection and crack. Therefore,in order to ensure the safety of the bridge during construction and using process,bridge structure deformation and the force must be calculated and monitored to graspthe true state of the bridge and ensure the normal use of the bridge.Yesanhe Bridge was taken as the background of this paper, finite element theoryand structural simulation theory were used synthetically to calculate and monitor themechanical properties of large span rigid frame bridge during construction and usingprocess. The author mainly carried out the following work.1.Finite element simulation model was built by finite element software Midas,factors like temperature、shrinkage and creep、prestress loss that affecting themechanical properties were analyzed, the result showed these factors have greatinfluence to deflection and stress.2. The mechanical properties of Yesanhe bridge in construction process havebeen calculated and monitored. The alignments in construction process and stressmonitor were introduced detailed. A comparative analysis between the monitoringvalues in construction process and theoretical values by calculation was done, and itshowed that stress values、deflections were close to the theoretical values relatively.3. The mechanical properties of Yesanhe Bridge in using process have beencalculated and monitored. According to the actual using situation of bridge structureand considering temperature、shrinkage and creep, deflections and stress values ofbridge were calculated in different periods. The measured and theoretical values wereanalyzed, the results showed that the measured values were close to theoretical values,the bridge structure is in safe using condition, these provide scientific guidance for the health monitoring of bridges.4. Shrinkage and creep of the bridge were analyzed by MADIS and based on themeasured results, different calculation of the creep models were compared andanalyzed, the results show that the calculation model recommended in the JTJ023-85can be used to calculate the shrinkage and creep of box bridges.