Study On The Damage Potential Ordering Of Design Ground Motion For Typical Bridge Structures

Design ground motions are required while doing dynamic analysis.Although some Codes give overall suggestions,the process of chosing design ground motion is of high autonomy.Nowadays,designers and scholars used to select El Centro,Taft or Wolong wave as design ground motions.The safety of structures which examined by these records can not be ensured for that some research points out other records may cause greater damage.How to choose input motion is of high research and engineering value.The main research content of this paper is to apply the concept of 'the severest design ground motion' to the bridge structure.Using the powerful nonlinear analysis software OpenSees,models of bridge piers are analyzed by inputing large quentities ground motions.Selecting the top displacement of the pier as the control parameter,the sequence of design ground motion is obtained.The main work are as follows:(1)the history and development status of the global strong earthquake database are summarized,the recording characteristics of each database are collated,the strong motion data set based on the PEER NGA-West2 is determined and.(2)the ground motion parameters of the ground motion damage potential are analyzed,the correlation between each other is obtained,and six relative independent parameters of PGA,PGV,PGD,CAV,Ia and Ds5-75 are obtained,and the data set records are sorted.(3)the analysis of the piers is carried out by using OpenSees.Taking the maximum top displacement of pier as an index,the sequence of damage potential of design ground motions is obtained.By analyzing the ordering law,the order of ground motion is related to the amplitude and structure.When the amplitude is low,the elastic acceleration spectrum near the structure period can reflect structure response.While at higher amplitudes,the longer period acceleration response spectrum and velocity or displacement parameters can better reflect the seismic damage potential.(4)through the response spectrum and finite element analysis,the influence of record PGA on structure response is analyzed.The results show that a higher PGA means higer spectrum response in short periods and lower spectrum response in long periods.Higher PGA will not influence structure response at low amplitude significantly but will cause lower damage at high amplitude,so a high scaling factor may increase the damage potential.