Horizontal mechanical behavior of elastomeric bearings under eccentric vertical loading: Full-scale tests and analytical modeling

In general, elastomeric bearings are designed to sustain axial vertical loads, and the interaction between the vertical and horizontal mechanical behaviors of bearings have been researched in previous studies. However, elastomeric bearings are subjected to eccentric vertical loads in some engineering projects. For the purpose of investigating the influence of eccentricity in vertical loads on the horizontal mechanical behavior of elastomeric bearings, full-scale bearing tests were designed and conducted. The test results show that the hysteresis loops obtained in the eccentric loading tests are quite asymmetrical compared to those of the axial loading tests. The difference between the measured shear forces at two mirror symmetry points increases with increasing shear strain and vertical load. The skeleton curves of the hysteresis loops rotate about the point that mirrors the eccentric loading center. In addition, the horizontal stiffness of the skeleton curves obtained in the eccentric loading tests is smaller in the eccentricity direction compared to that of the axial loading tests. On the basis of the test observations, an analytical model is developed within the framework of the Koh-Kelly model to predict the horizontal mechanical behavior of elastomeric bearings under eccentric vertical loads. The analytical model simulates the test results well and can reproduce the rotation center of the skeleton curves observed in the eccentric loading tests.