Seismic Design Method And Experimental Study On Rigid-Frame Through Tied-Arch Bridges

The rigid-frame through tied-arch bridge is a new kind of bridge style in China, which has developed from the tied arch bridge. The rigid-frame through tied-arch bridge is a hybrid structure, which consists of piers, arches, ties, hangers and deck system. It is also characterized by the rigid joints which connecting arches with piers and the horizontal thrust of arch ends balanced by its ties. During the development of more than one decade, hundreds of this kind bridge, of which the longest span is 280m, have been constructed because of its good structural behaviors, excellent spanning capacity and convenient construction. So the rigid-frame through tied-arch bridge becomes one of the main styles in urban bridge construction, and the important component of the urban transportation lifeline.However, there are several problems in the seismic design and research as followings: the current specification of seismic design for highway bridges lags behind the demand of the project practice both in seismic theory and design details. Existing researches on the seismic performance of the piers and the effects of piers are insufficient. Especially, when it is mentioned to the effect of the seismic performance of rigid-frame through tied-arch bridges affected by piers and the seismic design for the low piers, the researches are scarce. The seismic method is single. When the absorbing of vibration bearing or isolator could not been used, researches on reducing the structure earthquake response are lacking. In addition, researches on the interaction of the structure seismic performance of both sides of the expansion joints and the structure seismic performance under aftershock are also scarce.In order to solving the above problems, the author researches the seismic performance of rigid- frame through tied-arch bridges according to two aspects, including theory analysis and experimental study. One aspect is studying the seismic performance of the rigid-frame through tied-arch bridge as an unattached system, which includes researching the effect of the dynamic characteristics affected by pier stiffness, seeking the new seismic design method for improving the performance of piers and reducing the whole structure seismic response and analyzing preliminarily the structure performance under aftershock. The other aspect is studying the seismic performance according to the whole route whose main purpose is investigating the effect of pounding between rigid-frame through tied-arch bridges and the approaches, analyzing the main influence factors of pounding, attaining the measures for weakening the pounding and avoiding girders unseating.1. Dynamic Characteristics of Rigid-Frame Through Tied-Arch Bridges and Parameters Analysis The characteristics of natural vibration frequency and modals are analyzed, setting the...