Simulation And Experiment Research On The Seismic Performance Of The Multi-stage Timely Control Connection Device

Earthquake is a kind of natural disasters which are extremely destructive.In the past 40 years,earthquakes have occurred frequently all over the world.The bridge structure suffered varying degrees of damage in the previous earthquakes and the continuous beam bridge structures suffered the most serious damage.Traditional seismic isolation technology mostly needs to sacrifice displacement to improve the seismic performance of a continuous beam bridge,which has obvious technical defects.Moreover,most seismic isolation bearings have not changed the current situation that the fixed piers of continuous beam bridges bear the huge inertial force individually generated by the upper beam body under the action of earthquakes and the existing seismic potential of the movable piers of continuous beam bridges has not been effectively utilized.In order to effectively utilize the existing seismic potential of the movable piers of continuous beam bridges,many scholars have introduced locking control technology into the seismic design of continuous beam bridges through research,using the seismic response generated by the continuous beam bridge structure under the action of earthquakes to activate the installation between the beam and the movable piers.The locking devices allow the beam and the movable piers to be temporarily connected under the action of earthquakes to achieve the purpose of cooperating force on the movable pier and the fixed pier,so as to effectively utilize the existing seismic potential of the movable pier and reduce the seismic pressure of the fixed pier.However,the connection stiffness of the existing locking devices is mostly fixed and cannot effectively adapt to the connection requirements under different ground motions.Unsuitable connection stiffness may lead to problems such as increased overall seismic response of the continuous beam bridge and poor damping effect.In this context,the task force proposes a kind of "multi-stage timely control connection" device which is known as the MTC device.This dissertation has carried out researches on the optimization and improvement of MTC devices,the simulation and test of mechanical properties and parameter effects,and the application of vibration reduction.The main research contents are as follows:(1)The structural form of the MTC device was improved,the working principle of the MTC device was explained,the mechanical model of the MTC device was established and the performance requirements and connection stiffness calculation methods of the MTC device in different working stages were proposed;the tensile performance test of related materials was carried out and the results were obtained.The parameters such as stress-strain curve and steel modulus were studied.The stiffness value principle of the MTC device and the design method of energy dissipation plates was studied.(2)program design and experimental research of the pseudo-static test of the MTC device was carried out and the relevant analysis was carried out on the main mechanical performance indicators such as hysteresis performance,skeleton curve and equivalent viscosity coefficient.The finite element models of the MTC device were established and the rationality of the finite element models were verified by comparing the results of numerical simulation of the results of the pseudo-static test.(3)Based on the structural characteristics and working principle of the MTC device,the influencing parameters of the MTC device were analyzed and the connection stiffness,yield load,ultimate load,hysteresis curve,equivalent viscous damping coefficient and connection stiffness correction coefficient of the MTC device were used as indicators.The general law of the influence of each parameter on the performance indicators of the MTC device was obtained by the research on the influence of parameters such as the length,height,thickness of the bottom side and the separation distance of the energy-consuming plates.(4)In order to explore the primary and secondary order of the impact of each influencing parameter on the seismic performance of the MTC device,the significance analysis of the influence of the MTC device connection stiffness,energy dissipation capacity,ultimate load and connection stiffness correction coefficient parameters was carried out based on the orthogonal experiment design.Based on the range analysis and variance analysis,the main factors and secondary factors that affect the mechanical performance of the MTC device were obtained.The basic flow of the seismic design of the continuous beam bridge with the MTC device is proposed according to the results of the particularized analysis of the mechanical properties of the MTC device.(5)The finite element model of a seven-span continuous beam bridge was used as the research object to carry out nonlinear time history analysis to explore the damping effect of the MTC device under the action of small and large earthquakes considering the effect of traveling waves.The span of the continuous beam bridge and the height of the piers were changed to analyze the applicability of the MTC devices in different continuous beam bridges on this basis.