Research On The Performance Deterioration Law Of High Damping Rubber Bearings Under Seawater Freeze-thaw Cycle

In recent years,the state has continued to strengthen its investment in infrastructure construction,with a large number of high-tech,high-investment and long-span Bridges across rivers and seas completed.The appearance of the cross-sea bridge will greatly reduce the fuel consumption and travel time between the key coastal cities,and play a key role in promoting the economic development of the two coastal cities,upgrading the regional industrial structure and balancing the regional economy.In the northern region where winter is cold and freeze-thaw alternates,the cross-sea bridge is affected by various factors such as dead weight,upper live load,waves,ocean currents,tides and wind,etc.,and its durability is also affected by the effect of freeze-thaw cycle on the structure and isolation support of the cross-sea bridge.Under the comprehensive influence of sea erosion environment and freeze-thaw environment,the corrosion damage of the bridge structure,such as protective layer falling off,steel corrosion,concrete damage and cracking,is far more serious than that of the bridge structure in the inland environment.Research on the durability of the high damping rubber isolation bearings at home and abroad focused on the support of the thermal oxidation,creep and high damping rubber,and the research range for many inland bridge and use high damping rubber bearing,Bridges in Marine environment with high damping isolation rubber bearing under the action of freeze-thaw cycle of degradation is less research.Under freeze-thaw cycles in winter environment,coastal bridge structure using high damping rubber isolation bearing and bridge main body structure,joint by alternation of the freeze-thaw cycle,sea water environment,therefore,to the Marine environment under the action of freeze-thaw cycle of high damping rubber isolation bearing degradation performance study is very necessary,the results of high damping rubber bearing in offshore engineering application promotion,cross-sea bridge whole life performance assessment provides experimental data and theoretical basis.Based on the high damping rubber isolation bearing and same batch production and processing of high damping rubber material as the main research object,in combination with the practical environment of bohai bay in winter and laboratory existing experimental conditions,with reference to domestic and foreign about the degradation of concrete under freeze-thaw cycles,the rubber bearing performance of related research,the high damping rubber isolation bearing and high damping rubber material to carry out laboratory artificial accelerated water freezing and thawing cycle test.Specific research contents and results are as follows:(1)According to the sea-crossing bridge with high damping rubber isolation bearing in bohai bay of actual conditions,the Marine environment and the freeze-thaw cycle reference related literature,the analysis of the actual bohai bay freeze-thaw cycle of environment and laboratory artificial accelerated freeze-thaw cycle test of inner link,and formulate laboratory artificial accelerated freeze-thaw cycle test plan and test conditions.(2)The laboratory freeze-thaw cycle test of artificially accelerated seawater was carried out simultaneously for the high-damping rubber isolation bearing and the high-damping rubber material,and the mechanical properties of the high-damping rubber isolation bearing and the high-damping rubber material were measured regularly.High damping rubber isolation bearings are analyzed with the high damping rubber material mechanics performance of oceanic freeze-thaw cycle effect time change rule of the process,and through the study of the formula of the related data fitting,get high damping rubber material and bearing in the sea under the action of freeze-thaw cycle performance degradation time varying law of time-varying constitutive model parameters of rubber material is put forward as reference for engineering practice.(3)To establish the high damping rubber isolation bearings of ABAQUS finite element model,using the fitting of the time-varying constitutive model parameters of rubber material,establish the mechanical properties of high damping rubber isolation bearing finite element model,further analysis of high damping rubber isolation bearing mechanical properties with the ocean under the action of freeze-thaw cycle time,and with high damping rubber isolation bearing in the sea under the action of freeze-thaw cycle and comparing the variation law of mechanics performance test results of validation,finally comprehensive analysis of the water of the sea under the action of freeze-thaw cycle the deteriorating law of the high damping rubber isolation bearings.