Research On Parameters Of PC Cable-stayed Bridge Based On Site Test

With the wide application of PC cable-stayed bridge,the control of its construction and operation is becoming more and more important.In order to establish bridge management data,health monitoring and damage assessment,it is necessary to master the actual parameters of bridge structure.In general,due to the discreteness of material parameters and the construction error of the PC cable-stayed bridge built on the basis of the design drawings,there is a difference between the bridge stress state and the design expectation in the completion stage.Therefore,the response caused by subsequent loads(live load and abnormal load)is also unpredictable.Detailed test data(such as deflection and cable force data)can be grasped during the construction control of long span bridges.Based on the field measured data of construction control and the mechanical characteristics of PC cable-stayed bridge,this paper divides the whole bridge structure into several parameter groups and uses the static response surface method to modify the structural parameter value,and then obtains the finite element model after parameter modification.On the basis of collecting the theory of model modification,this paper summarizes the method of parameter identification and correction of PC cable-stayed bridge based on the test data of construction process.The numerical model of a cable stayed bridge was revised and verified,and the reliability of the method was confirmed.Then,with a PC cable-stayed bridge under construction as the support project.Based on the method proposed in Chapter 3,the finite element design model is modified by field test data.By comparing the calculated values of the modified model and the design model with the field measured values,it is proved that the modified structural parameters in this paper are closer to the real values,and the modified parameters in this paper are reliable.Based on this model,the thrust force of the main span closed top and the secondary cable force are recalculated,and the optimum design of the adjusting cable force is carried out.The deflection value,the stress value and the cable force value of the main girder are predicted.Finally,the stress state of the bridge during operation is predicted by the model,which reflects the difference between the design state and the design state.Based on this model,the bearing capacity of the bridge in operation stage is studied according to the current code,and the bridge has a certain safety reserve.