Seismic Performance And Vulnerability Studies Of The Continuous Rigid Frame Bridge Based On Different Cross-section Piers

With the advantages of high capacity, light weight, easy construction, etc, the concrete-filled steel tubular structure is more and more popular in construction industry. In bridge engineering, this structure is increasingly being used. But as piers, especially its study on seismic performance of high pier is still small. As a irregular bridge, its seismic performance has significance on post-earthquake repair works and economic loss estimation.The main work of this dissertation is described as followed. First, taking the Jiro river bridge on expressway where located between Chishui to Wangmo in Guizhou province as engineering background, this paper designed two concrete-filled piers with different connections and carried out Pushover analysis based on same carrying capacity. The hysteretic curves and skeleton curves of concrete-filled piers and original pier were got by Pushover analysis. And the seismic performance, such as hysteretic dissipation, energy dissipation, ductility and stiffness characteristics were compared between concrete-filled piers and original pier. The results show that concrete-filled steel bridge piers exhibit much better seismic behavior than original pier in condition of the same carrying capacity. The hysteretic loops of the concrete-filled steel bridge piers are much fuller than the original pier. The energy dissipation ability and the ductility of the former are better than of the latter. And the stiffness degradation of the former is slower than of the latter. With the increase of aixial compression ratio, the connections of concrete-filled steel piers affect slightly the seismic performance of the overall pier. Secondly, the article elaborated the building process of fiber element model in OpenSees, as well as the selecting basis of material constitutive model and section stiffness. Finally, in the basis of concrete-filled steel piers and rectangular hollow piers, the full-bridge dynamic models were established and the seismic response and the vulnerability were analyzed. The results show that the rectangular hollow piers are more prone to damage than the concrete-filled steel piers in the same seismic conditions.