Analysis On Deflection Control Of Continuous Rigid Frame Bridge Based On Adaptive System

The main beam of the continuous rigid frame bridge has strong bending and torsional stiffness,and the flexibility of the piers can adapt to the structural deformation caused by factors such as load,creep and temperature,so it can meet the structural stress requirements when the span is large.However,while the continuous rigid frame bridge is widely used,the excessive deflection of some bridges have threatened structural safety.Therefore,it is necessary to take measures to control the deflection of the continuous rigid frame bridge.In this paper,the adaptive system applied to the deflection control of continuous rigid frame bridge is studied based on the engineering background of the Liye Super Maior Bridge.The main contents and conclusions are as follows:(1)The advantages and disadvantages of Kalman filter method,BP neural network and least square method are compared,and it is determined that the least square method can be used for parameter identification of the continuous rigid frame bridge during the construction phase,and the grey model and the finite element model after parameter modification are used to complete the feedback calculation of the control quantity,so as to establish the relatively complete control theory of the adaptive system.(2)By comparing the sensitivity coefficients of various parameters,it is determined that the main factors affecting the structural deflection change of the cantilever casting stage are the bulk density and tension control stress of beam segment,and the least square method is used to identify the parameters of these two factors and adjust the finite element model,which reduces the deviation between the theoretical value and the measured value of the structural deflection.(3)Based on the measured value of the structural deflection and the theoretical value calculated by the finite element model after parameter modification,a metabolic grey model is established and its accuracy is checked,and the original data suitable for the deflection prediction of the Liye Super Maior Bridge is found.Using the method of multi-point moving average to optimize the grey model,through the analysis of the calculation results,it can be seen that compared with the theoretical value of the deflection calculated by the finite element model after the parameter correction,the predicted value of the deflection before and after the optimization of the grey model is closer to the measured value of the project,and the applicability and inspection accuracy of the optimized grey model are higher,indicating its feasibility for the adaptive control system of the continuous rigid frame bridge.The research results of this paper have certain guiding significance for the deflection control of continuous rigid frame bridge.