Seismic Performance Design Method Of RC Bridge Piers Based On Genetic Algorithm

Earthquake occurrs frequently in our country, resulting in huge economic losses and casualties. During seismic damage of bridges,destruction of piers could lead to a directly collapse or overturning of the bridge which is difficult to repair after the earthquake. Idea of seismic design that simply aming at ensuring the safety of lives,as well as method that based on strength is not enough for today’s social development. Idea of performance-based seismic design attracts much attentions of researchs now. However,in order to achieve the requirements of seismic performance, the performance-based seismic design of bridge piers needs a repeatedly calculating of the reinforcment, which is usually tedious.Further studies are required to avoid this process.In this dissertation,the genetic algorithm is applied to calculate the range of the reinforcement ratio that satisfies both displacement ductility and bearing capacity. We also propose the seismic design method of RC bridge piers directly based on performance requirements. Main contents and conclusions are as follows:(1)We implement the genetic algorithm in corresponding calculations.The reinforcement programme by which piers can exactly achieve the desired displacement ductility ratio or flexural capacity is calculated using this algorithm.Validity of the algorithm is excellent.(2)A number of parameters in the algorithm which impacts the accuracy and the speed of the algorithm are determined.(3)The reinforcement ratio is calculated by this algorithm with a changing expected displacement ductility ratio and flexural capacity. Then,range of the reinforcement ratio which satisfyes the displacement ductility and the bearing capacity is derived by analyzing the variation of the reinforcement ratio. When the range of reinforcement ratio does not exist,we calculate a reinforcement scheme which satisfies the design requirements by adjusting stirrups and longitudinal reinforcement.(4)In order to verify the feasibility of the seismic performance design method of RC bridge piers based on genetic algorithm, we give a seismic design example of a circular sectional pier as well as a rectangular sectional pier in this paper.