Optimization Of Design Parameters For Seismic Response Of Continuous Rigid Frame Bridges

The continuous rigid frame bridge has the mechanical characteristics of the continuous beam bridge and the T-shaped rigid frame bridge.Its force is reasonable,its appearance is simple and beautiful,it has good driving conditions,and its seismic performance is good.At the same time,its construction cost is low and the construction method is mature.Large spanning capacity and adaptability to terrain and geological conditions are good,so continuous rigid frame bridges have been widely used in practical projects.However,the design of continuous rigid-frame bridges is mostly based on experience and supplemented by calculations.Such designs are often too conservative and there is also the inheritance of design flaws.In order to make the design of the continuous rigid frame bridge more scientific and economic,it is necessary to optimize the dynamic response of the design parameters of the continuous rigid frame bridge based on the existing design experience.However,in the current optimization study of continuous rigid frame bridges,there are problems such as incomplete selection of optimization variables,unclear optimization objectives,over-optimized optimization goals,and the selection of optimization algorithms,and there are no corresponding results for the optimization results under orthogonal test.The comparison verification,and whether the optimization results of the upper and lower design parameters are considered better than when only the lower design parameters are considered.In response to the above problems,this paper mainly completes the following aspects of work:(1)According to the influence of different design parameters on the force of the continuous rigid frame bridge,the design variables and design constants during optimization are determined.In the design parameters of the continuous rigid frame bridge,the distance between the thin-wall piers,the thickness of the thin-walled piers,the thickness of the thin-wall piers and the number of horizontal beams are the design variables.The rest of the design parameters are regarded as design constants.In the upper design parameters of the continuous rigid frame bridge,the mid-span ratio is the design variable,and the rest of the design parameters are considered as design constants.Under the consideration of the overall parameters of the continuous rigid frame bridge,the distance between the thin-walled piers,the thickness of the thin-walled piers,the thickness of the thin-walled piers,the number of the horizontal beam,and the mid-span ratio are the design variables.The rest of the design parameters are As a design constant.(2)For the optimization goal of continuous rigid frame bridges,the objective of optimization is to minimize the ratio of actual effect and allowable effect and to minimize the fatigue damage factor under earthquake.(3)Summarize the parameters of the continuous rigid frame bridges that have been built at home and abroad,and draw the corresponding scope of use.For the optimization goal of the continuous rigid frame bridge,under the action of earthquake,according to different seismic response conditions,the ductility corner of the pier bottom under the effect of the E1 elastic time history and the minimum requirement of the flexural capacity of the pier bottom and the E2elastic-plastic time course are proposed.There are four types of optimization objectives with the smallest demand ratio,the smallest fatigue damage coefficient,the required ratio of ductile corners,and the fatigue damage coefficient.(4)In the selection of the optimization algorithm,this paper adopts the minimum distance ideal point method in the evaluation function method to perform multi-objective optimization according to the situation that the multi-objective function simultaneously takes the optimal solution.(5)Using the dynamic time history analysis method,the lower parameter combination test model under orthogonal test is calculated and analyzed,and the degree of influence of the optimal test combination and different design parameters on the test under seismic response is obtained.(6)Based on the selection of random combinations in the Java language,dynamic time history analysis is performed to obtain the optimal combination comparison between the optimal test set and the orthogonal test.(7)Overall consideration of the design parameters of the upper and lower parts,and dynamic time history analysis,to obtain the influence of the optimal test combination and different design parameters under orthogonal test on the seismic response,compared with the optimal combination considering only the lower design parameters.