Research On The Restoring Force Models Of High Damping Rubber Bearings

In the field of seismic research, it has been the main subject to find more effective means to resist seismic earthquake damage to structures. Base isolation technology has significant advantages in structural seismic control and disaster prevention and reduction. It has been widely used in the constructions and bridges.The appearance of the laminated rubber bearings provides an important foundation to the development of base isolation technology. At present, lead rubber bearings is widely used in the isolation design of constructions and bridges. The study of the mechanical properties and the restoring force model of HDR is still shallow. The mechanical properties of the HDR is complex, with many factors,such as the strain amplitude, vertical stress, load frequency, load sequence and so on. It’s because of the complex nature of HDR, there are still no one unified model to describe the restoring force of the HDR.In order to grasp the characteristics of HDR under earthquake performance more accurately, and to ensure the reliability of design and analysis, this paper studies the influence of varying vertical load and shear strain on the shear mechanical properties of high damping rubber bearing through experiment under the support of National Natural Science Foundation of China(Study on the Multi Direction Coupling Mechanical Properties and Restoring Force Model of the Base Isolated Laminated Rubber Bearing(U1204502)). Base on the results of the analysis, to establish the restoring force model of high damping rubber. The main contents are as follows:(1)By the compression shear test of unidirectional and bidirectional on HDR,study the correlation of shear strain、vertical stress of the mechanical properties of the HDR, analysis the effect of shear strain on vertical stress correlation and the effect of vertical force on shear strain correlation, research the coupling effect on the bearing performance through comparing the X-direction and unidirectional compression shear test results;(2)Analyzing the hysteretic characteristics of the HDR and the influencing factors, combining the analysis results, select a appropriate model to improve,establishing a model to reflect the correlation of shear strain 、 vertical stress, then comparing the calculated results with the experimental results to verify the effectiveness of the unidirectional model;(3)Expand the unidirectional restoring force model to bidirectional model,combining with results of the bidirectional test, establish a model reflecting the correlation of shear strain 、 vertical stress and the coupling effect of the HDR,compare the calculated results with the experimental results to verify the effectiveness of the bidirectional model.Found that the mechanical properties of the bearings having relation with not only shear strain、vertical stress, but also the amplitude of strain. The performances of the bearings are difference between the unidirectional and bidirectional tests. Based on the analysis of test results, selecting the appropriate restoring force model, to improve the model to reflect the correlation of shear strain 、 vertical stress by considering the above impact factors and the hysteretic characteristics of HDR. To verify the validity of the model, comparing the results of the compression-shear test with the modeling analysis results, the results show that the model can well reflect the restoring force characteristics of high damping rubber bearing.