Research On Seismic Response Characteristics Of Long-span Rigid Frame Bridge With High Piers

In recent years, the global earthquake frequency, and China , as anearthquake-prone countries, once suffered an earthquake, especially for bridge, whichis the lifeline project, it will give people and their country a serious even devastatingconsequences. With expressway extending to mountainousregions, long-span rigidframe bridge with high piers has become the main type of bridge across the plateaugully，big rivers and mountains. This kind of large-span and high pier bridge is morecomplex in eismics response as aseismic design than a medium&small span bridge,Such as influenced obviously by high order modes ,the need to consider theearthquake space characteristics, the pile-soil interaction,as well as all kinds ofcomplicated nonlinear effect, which are yet to be studied further. Choosing alarge-span and a hige pier continuous frame bridge named Zhou Jiagou, which locatesin highway(Chengdu to Zigong to Luzhou) in Sichuan province as engineeringbackground, while studying the earthquake response characteristics of a actual duallimb thin-walled large high pier continuous frame bridge in seismic impact analysischapter of bridge structural parameters ,which has important significance for morecomprehensive study of the law of seismic response of such kind birdge and ourcoutry’bridge aseismic design.This paper mainly finished the following work:(1) it briefly introduces the cause of seismic damage of bridges，the basicmethods of preventing earhtquake，the present research situation , existing problemsas well as several main impact factors of the earthquake response of bridges.(2) By using the finite element program Midas Civil ,the paper establishes twokinds of finite element model of Zhou Jiagou:the pier bottom consolidation model andconsddering pile soil interaction model,comparing such as their natural vibrationfrequency and the corresponding vibration mode of the dynamic properties,etc.(3) Based on the bridge seismic theory, combined with the site conditions andseismic zoning map, inputing longitudinal and transverse Taft seismic waves to thetwo bridge models respectively for elastic dynamic time-history analysis,throughthese steps the paper sums up the influence mechanism of the different incentivedirection and pile-soil effect on displacement and neternal force of key section of the bridge.(4) By comparing Earthquakes traveling wave effect time history analysis withearthquake consistent incentive results,it concludes that how traveling wave effecteffects different internal force compositons from different members of the bridge.(5) Based on the bridge anti-seismic concept design,by comparing earthquakeresistant capability of rigid frame combined continuous beam bridges with continuousrigid frame bridge,and double-limb thin wall pier with single columnar type pier,thepaper can provide references for seismic design of bridges.