Displacement Response Spectrum Method For Seismic Performance Analysis Of Pile-supported Wharve In Liquefiable Soils

Pile-supported wharves are mostly used in ports engineering.With the implementation of the Belt and Road Initiative,port construction in the countries along the initiative is booming,and many Chinese enterprises have also been involved.But the countries along the "One Belt And One Road" are mostly located in the earthquake zone,and earthquakes occur frequently.In history,earthquakes have caused severe damage to many ports and huge economic losses.The key to improve the resistance of structures to earthquakes is scientific and effective seismic design theory,and people gradually shift their attention to the bearing capacity to the performance,especially the displacement parameters of structures,and gradually form the displacement based seismic design method,while the main design method in China is still based on force design.It is of great significance to study the seismic performance of piled wharfs,which are mostly built in liquefiable sites and whose mechanism is complex under the action of earthquake.In view of this,this article by the pile-supported wharf as the research object,by using numerical simulation method,and explores the liquefaction liquefied site of piled wharf in the near and far field site vibration under the action of seismic response of the similarities and differences,and to explore the influence of site liquefaction for displacement response spectrum,and introduced based on the displacement response spectrum method for solving structural seismic demand,and compared with the results of nonlinear time history analysis.The main research contents and achievements are summarized as follows:First,in view of the liquefied sites high-rising deck piled wharf structure seismic interaction centrifuge test,build the numerical modeling of seismic response analysis and numerical simulation of soil pore water pressure,the acceleration and displacement of soil and pile bending moment and displacement of the deck in comparison with the test results,to verify the correctness of the numerical model.Based on this numerical model,the influences of parameters such as the length of embedded pile,the flexural rigidity of pile and the thickness of weak soil layer on the site response and internal force of pile are investigated.Then,using similar numerical modeling techniques,the numerical model of non-liquefaction site pile-soil-deck piled wharf structure is established.In this paper,six near-field and far-field earthquakes are selected to analyze the similarities and differences between the seismic response of soil mass and the seismic response of structure,and further explore the differences between the seismic response of liquefaction site under near-field and far-field earthquakes.It is found that the effect of near-field vibration should be paid attention to in the design of high pile wharf,and it is verified that the displacement response is more sensitive than the acceleration response,so it is suggested to replace the acceleration response spectrum with displacement response spectrum in the seismic demand analysis of port structures.Subsequently,displacement response spectrum is an important content based on displacement seismic design theory,and the seismic demand of structures in liquefiable sites will be higher,so the effect of liquefaction on displacement response spectrum is preliminarily explored.The seismic records of four stations,including Port Island Station and Kobe Station,were analyzed.Liquefaction phenomenon was observed in all these sites.Furthermore,the displacement response spectrum of these ground motions is calculated,standardized and linear fitting is carried out,and compared with the response spectrum of class D site given in the European specification,it is found that the response spectrum of the specification tends to be unsafe in a longer period.Finally,this paper presents a system based on displacement response spectrum of piled wharf seismic performance analysis method of selecting an operating mode were analyzed,and the use of the fixed displacement response spectrum of obtaining its seismic requirements,and comparing with the results of nonlinear time history analysis and structure,found that the use of this method for liquefied sites piled wharf seismic performance analysis is a scientific and effective.This paper provides some ideas for the seismic performance research and seismic design of similar pile-supported wharf structures.