Research On Seismic Design And Optimal Placement Of Steel Frame Structures Equipped With Dampers

The displacement-based seismic design of passive control structures with additional viscous dampers is carried out,and the damper parameters required by the structure can be determined under a given target displacement.The adaptive genetic algorithm can improve the crossover operator and mutation operator to improve the evolution speed and search accuracy of the algorithm.Parallel genetic algorithm can make full use of computer performance to improve evolution efficiency,and fast non-dominated sorting genetic algorithm(NSGA-II)can achieve multi-objective optimization of structural dampers arrangement.This paper adopts the displacement-based seismic design method to design the viscous damper,applies the adaptive crossover operator and the mutation operator to the genetic algorithm,and then selects the single objective and multi objective functions to optimize the placement of the dampers,and put forward suggestions for the arrangement of frame structure dampers.The main work is as follows:(1)Displacement-based seismic design is carried out directly on the structure with viscous dampers.According to the target displacement of the frame structure under the set performance level,the structure is equivalent to a single degree of freedom system.According to the equivalent damping ratio,the equivalent period of the structure is determined by checking the displacement response spectrum,so as to obtain the base shear force and the equivalent lateral force of each layer,and then design the damper parameters according to the shear force distribution coefficient.A displacement-based seismic design of a multi-storey steel frame office building is carried out,and the additional viscous damper parameters required by the structure are calculated,and then the seismic damping effect of the passive control structure is evaluated.(2)An improved adaptive genetic algorithm is introduced,and the fitness function is applied to the algorithm to improve the crossover operator and mutation operator.Different from the crossover probability and mutation probability of the traditional genetic algorithm,the crossover and mutation operators of the adaptive genetic algorithm will change according to the fitness value of the individual,which can accelerate the evolution of the population.(3)The improved crossover and mutation operators are applied to the coarse-grainedmaster-slave parallel genetic algorithm to optimize the placement of the dampers.The algorithm uses a coarse-grained model in the upper layer to divide the population into multiple subpopulations,and performs independent parallel calculations on each sub-population in the lower layer.Then,the algorithm is used to optimize the position of the dampers of a multi-layer steel frame structure with the displacement angle between floors as the objective function,and the damping rate is compared and evaluated between the optimal layout and the uncontrolled structure and the conventional layout.(4)Combining the fast non-dominated sorting genetic algorithm with the coarse-grainedmaster-slave parallel genetic algorithm,the multi-objective optimization of the position of the dampers on the steel frame is performed with the displacement angle between floors and floor acceleration as the objective function.The algorithm comprehensively considers the safety and comfort of the structure,and introduces the Praeto optimal solution,the crowding degree operator and the elite retention strategy operation.Subsequently,the algorithm is used to optimize the placement of the dampers of a multi-layer steel frame by multi-objective optimization,and the optimization results are compared with the damping rate of the uncontrolled and conventional arrangements to evaluate the effectiveness of the algorithm,and the multi-objective optimization of the steel frame is considered Suggestions on the arrangement of the middle damper.