Parameter Optimization Of Seismic Response Of A Low-rise Cable-stayed Bridge Based On Uniform Test

Based on the advantages of strong spanning capacity and low cost,the low-rise cable-stayed bridge has been widely respected in recent years.However,at present,China does not specify the relevant codes for seismic design of long-span irregular bridges.The seismic design is mostly based on experience,supplemented by calculations.Such designs are often too conservative,and there will be hereditary design flaws.In order to make the seismic design of the low-rise cable-stayed bridge more scientific and economical,it is necessary to optimize the dynamic response of the design parameters of the low-rise tower cable-stayed bridge based on the existing design experience.At present,in the optimization research of the low-rise tower cable-stayed bridge,there are problems in that the optimization variable selection is not comprehensive,the optimization target is not clear,the optimization target is too single,and the optimization algorithm selection has randomness.In view of the above problems,this paper mainly completes the following aspects of work.:(1)According to different design parameters,the design of the low-rise cable-stayed bridge is affected,and the design variables and design constants during optimization are determined.The spacing between the thin-walled piers of the two limbs,the thickness of the thin-walled pier,the ratio of the main span of the side and the height of the main tower are design variables,and the rest of the design parameters are regarded as design constants.(2)For the optimization goal of the low-rise cable-stayed bridge,the minimum ratio of the actual action effect and the allowable action effect and the minimum fatigue da mage coefficient under the action of the earthquake are the optimization objectives.(3)The parameters of the low-rise tower cable-stayed bridges that have been built at home and abroad are summarized and the corresponding scope of use is obtained.For the optimization goal of the low-rise cable-stayed bridge,under the action of earthquake,according to different seismic response conditions,the minimum ratio of the bending capacity of the pier foundation under E1 elastic time history and the ductility of the pier bottom under the E2 elastoplastic time history are proposed.Three types of optimization targets with minimum corner ratio and fatigue damage coefficient.(4)Using the dynamic time history analysis method,the parameter combination test model under uniform test is calculated and analyzed.Combined with regression analysis and stepwise regression analysis,the optimal test combination and different design parameters of theearthquake response are obtained.(5)In the selection of optimization algorithm,this paper adopts TOPSIS ideal point method for multi-objective optimization based on the multi-objective function taking the optimal solution at the same time.