| Laminated elastomeric rubber bearings designed with a large-scale earthquake have been widely employed in bridges since the 1995 Kobe Earthquake. However, some of such laminated elastomeric rubber bearings suffered severe damage including rupture or deep cracking into rubber due to the 2011 Great East Japan Earthquake. The seismic design specifications for highway bridges were revised in 2012 based on lessons learned from the 2011 Great East Japan Earthquake. Some additional technical requirements for the laminated elastomeric rubber bearings have been described in the specifications, so that those bearings could work adequately under a cyclic loading. This paper introduces recent PWRI research projects on verification of the mechanical properties of the laminated elastomeric rubber bearings and the effect of the seismic damage on the mechanical and material properties. More than 100 laminated rubber bearings manufactured recently in Japan were tested under the cyclic loading to examine the capacity of the shear strain, the stiffness and the property of damping. Furthermore, some laminated rubber bearings damaged with crack due to the earthquake and removed from a bridge were also tested, so that the effect of the cracking on the mechanical properties of the bearings. |
