Research On Application Of Response Surface Method Model Repair In Assessment Of Prestressed Concrete Beam Damage

The finite element model correction technique is to optimize the structure of the finite element model based on the design drawings and design parameters.The modified finite element theory model is closer to the physical structure in response to the load.The finite element model can be obtained to evaluate the stress and safety of the actual structure.The study of model correction technology makes the numerical theory analysis technology have important engineering significance for evaluating the bearing capacity of the beam body and predicting the stress response such as displacement deformation development.In this paper,the response surface correction method based on the measured data of static load on test site is studied to evaluate the load-bearing performance after beam cracking.On that basis,Based on the static load test data,a correction method for beam structure response surface was developed.It has practical engineering significanceThe main research work of the paper:1)Laboratory static load testSelection of 6 x 8 m long span prestressed concrete beams for site static load response test.Test data of beam structure under different prestressed force levels are obtained.The displacement deformation data of a total of 6 beams at the positions of L/4,2L/4,3L/4 and the measured values of strain across the middle upper edge and the bottom plate.To provide reliable field data for engineering application of finite element model correction technology for prestressed concrete structures2)Basic Theory and Steps of Response Surface MethodThe theory,steps,design of test method,parameter significance screening,fitting of response surface equation,precision rating of response surface equation,comparison of response data and test data under initial loading state of model are introduced and analysis3)Construction and Optimization of Theoretical ModelsA finite element theoretical model based on design drawings and material parameters is established.Through BBD experimental design method to carry out parameter saliency analysis,The prominent parameters were selected: concrete elastic modulus EC,concrete density,steel wire elastic modulus ES,prestressed steel bar applied temperature °C,Select the significant parameter and its cross term to fit the response surface equation.The constraint interval of displacement deformation data under combined static load is set.1)Optimizing the objective function and the constraint function with the software function optimization algorithm,Look for the best solution.2)Or solve the optimal solution of parameters in the form of genetic coding of genetic algorithms.Based on the results of two optimization algorithms,To observe the practicability of two optimization algorithms in model correction.4)Assessment of Beam Damage Based on Optimized Response Surface Model.Based on the optimized response surface model,Set up damage conditions and carry out BBD experimental design.Combined repeated damage condition data table for parameter saliency analysis,The response surface equation is fitted with significant parameters and their combined polynomials.The finite element model under damage condition is modified by setting the state variable with the test data after cracking.