The theoretical calculation,numerical simulation and tests were conducted to examine the recentering capability of the double concave curved surface(DCCS)isolators after earthquakes and evaluate existing expressions.The static and post-earthquake residual displacements of the DCCS isolators were compared and analyzed.The DCCS isolators with a design vertical load bearing capacity of 5 000 kN were taken for case study.Based on the static residual displacements calculated by theoretical formulas,quasi-static tests were performed to verify the recentering capacity of the isolators.Shake table tests were carried out to analyze the differences between the static residual displacements and the post-earthquake residual displacements.The finite element model of a typical simply-supported box girder railway bridge with spans of 32 m was developed in MIDAS Civil to analyze the post-earthquake residual displacement and recentering capacity of isolators in the contexts of one-time seismic wave input and two consecutive times of seismic wave input,respectively,by using a non-linear time history analysis method.It is shown that the static residual displacement of the isolator equals the product of the equivalent curvature radius and the equivalent friction coefficient of the isolator,and the static residual displacement of the recentering capacity of the isolator agrees well with the theoretical value,leaving a deviation of 4.92％.The average post-earthquake residual displacement between the results of the shake table test and the non-linear time history analysis is about 2 mm,lower than 5％of the static residual displacement.DCCS isolators prevent the occurrence of cumulative post-earthquake residual displacement in a bridge,displaying sound recentering capacity.It is not proper to evaluate the post-earthquake recentering capacity of the DCCS isolators using the static residual displacement.
关键词
桥梁工程/双曲面球型减隔震支座/震后自复位性能/残余位移/振动台试验/时程分析/有限元法
Key words
bridge engineering/double concave curved surface isolator/post-earthquake recentering capacity/residual displacement/shake table test/time history analysis/finite element method
维普
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