| The process of modernization is more and more dependent on communication and transportation with the rapid development of cities in the present day. Meanwhile, the earthquake-induced destruction to bridges in transportation networks will lead to more and more enormous damage to people's life and property as well as some other indirect pecuniary loss. The establishment of anti-seismic design method and the usage of efficient anti-seismic measures stand right on the earthquake-induced damage and its mechanism.Long-span continuous rigid bridge become one of the most popular structure forms due to the perfection of the pre-stressed concrete technique and the cantilever construction method. Bridges with great height are commonly needed to be built in mountainous area, which requests the bridges to have high and even hollow piers. Although the continuous rigid bridge owns merits of its anti-seismic performance as its pier and girder are fixed together, the earthquake-induced displacement of the piers'top will remarkably influence the inner force distribution, which may possibly cause partial damage to the bridge structure. In the recent decade years, pier columns'breaking down is presented as a new characteristic of earthquake-induced damage to bridge structures. The damage arises first of all from bridges'pier columns, which may result in the collapse of the whole bridge structure. Therefore, the analysis of seismic response of the bridges'pier is critical to the related research on the whole bridge structure. At present, the seismic performance of thin-wall pier and its ductility property are rarely researched and the statement about this field is mentioned scarcely in the codes for seismic design. It is a work of great significance to make research on the seismic performance of thin-wall pier, as it will supplement the codes for bridge seismic design of our country.Taking account of the situation of the research on the seismic response of large span bridge structures, making the use of the Xiaoshawan Yellow River Bridge of the Nei Mongol Autonomous Region as an example for analysis, according to the principle of multilevel design method, ductility design method for bridges subjected to fierce earthquake is introduced particularly in this thesis. A program from which the elastic-plasticity M-φcurve of the pier's cross-section can be made out is presented. The checking calculation for the pier's resistance of bend and shear is carried out. A new time-history analysis method is proposed based on the combination of Large Mass Method Theory and Clough Pseudo Static Displacement Theory. The equation of motion is derived, and the practical numerical method of this new theory is obtained. Comparing with the elder time-history theory of relative displacement, this new time-history theory can get the absolute displacement of Structures by taking the translation of ground base into account. At the meantime, the finite element modeling method, dynamic characteristics and seismic response characteristics of large span bridges are explored. The study shows that the spatial variability effects present significant influence on the seismic response; especially the wave-passage shows a great affect. |
