Exploration On Seismic Control Of Long-span Reinforced Concrete Arch Bridges

Based on the project of Xinyajiang Bridge of Panzhihua, the dissertation makes a tentative research into the seismic performance of long-span reinforced concrete box-typed arch bridge and its seismic control(No:50578168). The findings are as follows:1. By comparative study, the influence of changes in structure parameters of concrete arch bridge is systematically investigated. The author finds that, skewback supporting condition is the most influential factor influencing the natural vibration characteristics of long-span reinforced concrete box-typed arch bridgeThis finding provides the way to seismic control of concrete arch bridge。2 The dissertation makes a research into the seismic response of long-span reinforced concrete box-typed arch bridge by means of time-history response analysis under multidimensional seismic wave. It finds that , for long-span reinforced concrete box-typed arch bridge, the internal forces and the displacement should be controlled ,the internal forces is controlling factor and the displacement is uncontrolling factor.3. Research on shock absorption by transferring structure system. According to seismic control method of structure system transformation, a vibration reduction analysis of Xinyajiang Bridge is presented in this dissertation. The model that is changed connection mode between the main arch and foundation form hingeless arch to two hinged arch and added the damping to skewback is adopted in this dissertation. Based on it, the thought of shock absorption by transferring structure system is effective. The displacement is slightly increased within the standard requirements on the premise of the reducing of internal force.4.Based on seismic control of transferring structure system, the method of transferring structure system is developed in two aspects; 1)The method of seismic control by eccentricity at arch foot, eccentricity is generated between axial force and anixs at the time of bearing stiffness is changing.2) The method of deviation of arch axis.The displacement that is relative to supporting point changes the arch axis due to the changes of axial rigidity when the earthquake coming. To achieve the goal of seismic control by controlling the deviation of arch axis.5. The realizing way of deviation of arch axis method of transferring structure system is perfected deeply. And its working principle is explained.