Analysis Of Seismic Response Of High Piers And Long Span Continuous Rigid Frame Bridge

As one of the countries for earthquakes in the history,China is located in intersection region of two enormous eismotectonic systems in the word. Frequent occurrence of earthquakes threat to people's lives and property seriously. The damage of bridge structure which one of lifeline engineerings will increase the extent of secondary disasters and lead to even more serious losses. Therefore, it has greatly significance to ensure that the bridge safety under seismic.Recently, large and medium bridges are constructed rapidly as the high-speed development of our country's economy. Guidelines for Seismic Design of Highway Bridge (JTG/T B02-01——2008)is used at present only can deal with the bridges whose span under 150m,which can't meet the urgent needs of engineering design. uncertainty and complexity of the propagation mechanism of the earthquake lead to that two basic properties of seismic-randomness and should be fully recognized when seismic action loading on structure design. The ground motion is a complicated time-space process. There are some charcters about the seismic in the propagation,such as incoherence effect,wave-passage effect,site-respone effect and ect.It has been verified that the ground mtions inputting at different supports of large-span structures are different,which may be modeled by phase shifts and coherency losses.The phase shifs are caused by waves propagating,while the cohenrency losses can be attributed to many factors such as source mechanism,path and local site effects,etc.Studies on response of high-pier-long-span and continuous rigid-framework bridge have shown that the effects of muli-support excitations must be considered.Seismic response analysis are presented in this paper through taking a high-pier-long-span and continuous rigid-framework bridge as an example considering seismic input, structural characteristics,response anlysis of structure such three parameters,and the main contents are as following.①The paper establishes a whole analyse model of continuous rigid-frame bridge and calculates the result of vibration model analysis of it's natural vibration and natural frequency in ANSYS.②Response spectrum from Guidelines for Seismic Design of Highway Bridge is applied to analyse seismic respons including the influence study of single effect,namely ongitudinal vibration component, transverse vibration component and vertical vibration component,and the influence study of two effects assembly and three effects assembly.The influence of continuous rigid-framework bridge under vertical vibration component through analytical comparison of six vibrations.③Lage mass method is utilized to measuring the semisic effects of traveling wave.In the thesis, artificial seismic wave based on response spectrum of the bridge location is applied to study the influence of apparent wave velocities on continuous rigid-framework bridge.④Site-respone effect analysis is based on power spectrum. Power spectrum based on response spectrum at different sites as multi-support seismic indirectly to analyse the influence of site-respone effect on the bridge.