Seismic Response Analysis Of Long-Span Rigid Frame Bridge Subjected To Near-Fault Pulse-Like Ground Motions

In recent years, the successive straight-down type earthquake near cities led to a large infrastructure damage, life casualty and economic losses. The more complex near-fault pulse-like ground motions with more damage potential to structures are presented in these earthquakes. However, damage mechanism of the near-fault pulse-like ground motions on structures can't be well explained with current seismic thoery. With the Chongqing Guangyang bridge, the seismic response of long-span rigid frame bridges subjected to near-fault pulse-like ground motions are investigated in this study. The main works are summarized as following:(1) Several typical near-field effects are analysed firstly. Then the characteristics of the wave-form and response spectra for near-fault pulse-like ground motions are studied. And the feasibility of the simple pulse model is discussed for replacing the real near-fault ground motions in practice.(2) The response features are studied for concrete rigid frame bridge under near-fault ground motions are studied. The comparison is next conducted with response of bridge under the far-fault ground motions recorded in the same sites. The advice is given on seismic design bridge in the near-fault area. The seismic response is performed for bridge subjected to simple pulse model and real near-fault ground motions.(3) With a great number of ground motions, it is investigated for the correlation of the parameters of near-fault and far-fault ground motions with the response of long-span rigid frame bridges. And the damage potential of near-fault ground motions to long-span bridges is revealed.