Based On The Seismic Performance Of Urban Elevated Bridges Pushover Analysis And Assessment Methods

The viaduct has a very important practical significant on optimizing the regional traffic. Since the Wenchuan earthquake, research on seismic performance of the urban elevated bridge has been one of the priority subjects. Based on the Longjiang road viaduct, this paper mainly studied the seismic performance by pushover analysis. The following conclusions were obtained:(1) By analyzing the bridge dynamic characteristics, this paper obtained natural frequencies and mode shapes of the viaduct by using the Midas Civil software.(2) Because the demand spectrum curve intersected with the capacity spectrum curve, The viaduct structure had the seismic performance under the defense intensity.(3) By analyzing the different height-to-diameter ratio model, we obtained that the low-pier bridge controlled base shear force by increasing the height-to-diameter ratio while the high-pier bridge needs enhancing stability.(4) By studying the different section shape viaduct model, we obtained that the circular section is more suitable to the low-pier bridge because of the better lateral stiffness while the rectangle section is more suitable to the high-pier bridge.(5) Based on the damage principle, we got the damage index under the different fortification intensity by pushover analysis. The results showed that the viaduct structure meet the level of the fortification requirement.