Ultimate Compression Capacity of Unbonded Steel-Mesh Reinforced Elastomeric Bearings

Unbonded elastomeric bearings are commonly used in highway bridges in developing countries. However, they tend to slide uncontrollably during strong earthquakes. To this end, a novel bearing called the Unbonded Steel-Mesh Reinforced Rubber Bearing (USRB) is proposed. USRB applies flexible high-strength steel wire meshes, typically used in tires and screens, as reinforcement. This allows for controlled rolling of the elastomeric bearings to enable larger lateral deformation capacity and lower lateral stiffness. Nevertheless, the effect of the steel-mesh reinforcement on the vertical properties of USRB, particularly the ultimate compression capacity, remains unexplored. Therefore, this paper studied the ultimate compression capacity of USRB through experimental and numerical methods. One USRB prototype was fabricated and tested to identify the failure mechanism under vertical compression. Finite element modeling was then conducted to investigate the influence of various reinforcement characteristics on the ultimate compression capacity of USRBs, such as steel wire diameter, aperture size, and weight per unit area. The test demonstrates that USRB fails due to the tensile failure of steel wires in the mesh reinforcement. The FE results show that the mesh reinforcement can provide USRB with higher ultimate compression capacity by applying larger steel wire diameters, higher weights per unit area, and smaller aperture size. However, the superior lateral performance of USRBs is at the sacrifice of a lower ultimate compression capacity compared to steel-plate reinforced bearings. This study provides a research basis for the application of USRBs in bridges with high load demand and also demonstrates their potential to improve the seismic isolation performance under vertical seismic loadings.