Study On Shock Absorption Performance Of New 3D Global Yield Metal Dampers

The threat of earthquake disasters to bridges is very large,so bridge damping technology has always been a hot topic in the civil engineering community.Bridge seismic reduction and isolation reinforcement technology generally uses flexible bearings or seismic isolation bearings to replace traditional rigid bearings,and adds a seismic isolation layer between the bridge and the foundation to reduce the impact of earthquakes on the bridge.Among the commonly used additional dampers,metal dampers are widely used,but there are still many shortcomings in existing bridge metal dampers,such as low material utilization,energy consumption in only one direction,and non-working under small displacement.Therefore,a new three-dimensional global yield metal damper with energy consumption in any direction and small displacement is proposed.To study its seismic absorption effect in bridges,the main research contents and results of this paper are as follows:(1)Firstly,the overall seismic damage characteristics of the bridge were investigated and summarized from the perspectives of time and space,and then the attention was focused on various diseases of the connecting parts of the bridge bearing,and the seismic reduction and isolation design methods and empirical measures of the bridge support at home and abroad were comprehensively absorbed,on this basis,the design concept of bridge seismic reduction and isolation with clear purpose and clear thinking was formed,and finally a new three-dimensional global yield metal damper was proposed.(2)The design method,design concept and related formulas of simultaneous yield of full section of steel rod were discussed,and the guiding formula of simultaneous yield of full section of steel bar was verified and analyzed through Abaqus finite element simulation and full-scale test.The results show that the steel rod designed by the guiding formula has full-section yield characteristics.The stiffness errors of theoretical and simulated values and simulated values and simulated values and experimental values of full-section yield steel rods were 13.58% and 13.11%,respectively.The yield displacement errors were 11.65% and5.30%,respectively.The yield load errors were 3.45% and 6.85%,respectively.(3)Taking a certain underbearing arch bridge in Dongguan as an example,the finite element model of Midas civil full-bridge is established,and the calculation results under finite element static load(under self-weight and after paving in the second phase)are compared with the maximum vertical displacement of the main beam measured by construction,which verifies the correctness of the finite element modeling of the arch bridge.(4)The dynamic time history analysis method was used to calculate the dynamic response characteristics of the bridge bearings under the seven-degree E2 and E1 fortifications of the arch bridge,and the support reaction difference between the two calculations was used as the design index to determine the energy consumption requirements of the damper of the bridge bearings under earthquakes.Based on this,the material selection parameters of the new three-dimensional global yield metal damper are obtained,and the mechanical performance parameters of the metal damper are obtained through finite element simulation,which provides an important parameter basis for the subsequent dynamic time history damping analysis of the bridge.(5)Research on the shock absorption effect of the new three-dimensional global yield metal damper.The dynamic response characteristics of the metal damper under the seventh-degree E2 fortification condition of the down-bearing arch bridge were calculated and analyzed,and the dynamic response characteristics of the seven-degree E1 fortification without additional damper were compared and verified.The results show that after adding a new three-dimensional global yield metal damper to the arch bridge bearing,the bridge support reaction force can meet the expected shock absorption target.If displacement is used as the shock absorption index for analysis,after attaching the metal damper,the displacement shock absorption rate of the upper main beam is 22.4%-56.8%,the shock absorption rate of boom displacement is 19.7%-53.6%,and the shock absorption rate of arch rib displacement is15.5%-48.3%.