Research Of Seismic Isolation-Measures Of Bridge

The research of seismic isolation-measures of bridge is the important content of the seismic research,these isolation-measures can protect bridge from damage or reducing the level of damage by their specific function to reduce or cut off the transfer of the seismic load. This thesis propose some new design-concept on the basis of summing up principal damage characteristics in the past earthquake and the isolation-measures used extensively in the engineering practice,there are falling-off prevention measures,collision prevention measures and new style bearings for isolating seismic.The emphasis of the design-concept of these new measures is they don't resist seismic load by enforceable measures but allow their failure or damage for the bridge safety.This thesis propose design-concept by "care"not the enforceable "drag" in the past for preventing falling-off,it prevent falling-off by expending the support surface in the top of the pier,have higher availability;In the research of collision prevention measures,the thesis propose the concept of "hit-off" convexpiece,it has simple structure form and explicit form of force,and it is changed easily,the thesis also propose to install the rubber cushion at the end of beam to prevent the collision damagement;In the research of new style bearings for isolating seismic,the thesis propose the concept of "roller" bearing to isolate the seismic load,these measures all could reduce the seismic load highly at the top of the pier proofed by theoretical analysis.The thesis list the methods of calculating the largest relative displacement of the end of the beam and the top of the pier for guiding the above seismic isolation-measures,and use the MIDAS CIVIL to calculate by response spectrum method and time-history method,these methods of calculation are also practical in reality.