| In recent years,Long-span Rigid-framed Continuous Bridges with High Piers have found wide applications in regions like gully and gorge where geographic geomorphic conditions are limited. Many domestic and international experts have carried on a great deal of researches on mechanic characteristic and construction process of this type of bridge. Related research methods and achievements mostly concentrate on static force while they lack analysis in dynamics. Considering that bridges are the most vulnerable link in the transportation system, Once bridges are damaged in them, the transportation system will be crippled. Meanwhile, anti-quake relief and reconstruction work will face unexpected difficulties. dynamic researches on these irregular bridges like Long-span Rigid-framed Continuous Bridges with High Piers will make a significant difference. This thesis mainly analyzes seismic vulnerability of Long-span Rigid-framed Bridges with High Piers, and achieves the following work:I)After concluding and summarizing the structure, mechanical characteristics and the easily vulnerable parts of the Long-span Rigid-framed Continuous Bridges with High Piers systematically, determining analytic object of seismic vulnerability in this thesis, and presenting analytic procedure of seismic vulnerability, I have analyzed and researched on such important steps of analytics of seismic vulnerability: seismic wave selection and coordination, parameters of ground motion intensity selection, damage index selection and determination, finite element model and analytic methods, and vulnerability curves drawing methods.II)By employing the displacement ductility ratio damage index, I conduct researches on the seismic vulnerability of pier column. With the quality of the super-structure, the section form of pier column, span, and reinforcement ratio of pier column remaining unchanged,and the height of pier column changed, After analyzing the pier height’s influence on the vulnerability curves of Rigid-framed Continuous Bridges, I come to the conclusion: with the height of pier column increasing, the anti-vulnerability of bridges will get enhanced; otherwise it gets weakened.III)By employing the displacement ductility ratio damage index, I conduct researches on the seismic vulnerability of pier column. With the quality of the super-structure, the section form of pier column, span, and reinforcement ratio of pier column remain unchanged,and the tie beam’s quantity changed, I analyze the quantity setting of tie beam’s influence on the vulnerability curves of the Long-span Rigid-framed Continuous Bridge with High Piers. Finally it comes to the conclusion: with the quantity of tie beam increasing, the anti-vulnerability of bridges will get weaker: otherwise it gets enhanced. |
