The Seismic Response Characteristics And Reduce Isolation Study Of High And Low Pier Girder Bridges In Mountainous Areas

With the vigorous development of the western traffic, and more recently to theglobal earthquake-prone, due to the bridge in mountains across the ravine, valleys, hillsand other complex terrain, making the height of pier and adjacent pier are larger, alsomaking Stiffness difference of piers are larger. Then seismic response and failuremodes under earthquake piers are not the same. All of these brought greater difficultyfor bridge seismic design. Also it will have a great impact on the seismic performanceof the structure with Seismic Isolator measures. So the mountains high and low pierbeam bridge seismic performance research is increasingly urgent. First this articlethrough briefly introduce of the earthquake, the characteristics of seismic response ofthe bridge structure, the calculation method of the bridge structure seismic responses,and bridge seismic isolation technique. Then for the most typical high and low pierbeam bridge in the mountains, and follow its way across the obstacle divided into fourcategories, include unidirectional slop bridge, bridges across the hills, bridges acrossthe valley, and same height bridge. By means of large finite element software MidasCivil, construct three dimensional dynamic models. Using seismic time historyanalysis method, calculate the seismic response of the above four type bridges, andcalculate the seismic response with the lead core rubber isolation bearings. And alsocalculate rigidity of pier top and bridge pier stiffness. Finally, by comparing andanalysis the stiffness of the piers and the seismic force of bridge pier bottom, summedup the action of mechanical characteristics of high and low pier beam bridge under theearthquake. When input the earthquake along the bridge, the stress of the low pier (bigstiffness) is bigger, assume a major earthquake force. When input the earthquake crossthe bridge, the stress of the high pier (small stiffness) is bigger, assume a majorearthquake force. Adopted after the lead core rubber isolation bearings, it caneffectively reduce the earthquake force of bridge pier bottom, but when the pier heightreaches a certain height, the lead rubber bearing isolation effect will be reduced. Inorder to make the high and low pier bridge in mountains has better seismicperformance, bearing arrangement can be reasonably, bearing stiffness adjustment canbe reasonably, making the whole mass and stiffness of the bridge is more uniform andreasonable.