Large-scale cushion type bare and partially rubber filled mechanical couplers subjected to uniaxial cyclic loading

Large-scale bare mechanical coupler (BMC), and partially rubber-filled mechanical coupler (PFMC) were developed in this study. BMC and PFMC were created to utilize especially at high-performance hybrid post-tensioned rocking wall (HPRW) systems. BMC can couple adjoining HPRWs in the vertical direction as a yielding-type supplemental damper. PFMC can couple HPRWs to the foundation beam and/or adjacent HPRWs at the story level in the horizontal direction. It can function as a supplemental energy absorber with high bearing capacity and adequate lateral strength. Since BMC and PFMC are joined externally to HPRWs, they can be replaced easily after severe seismic excitation. The quasi-static cyclic shear and axial tests were carried out on BMCs and PFMCs to evaluate their hysteretic behaviour and determine their structural properties. The experimental parameters, besides the loading type, were the plate thickness of BMCs and the density of steel sheet layers at rubber blocks of PFMC. The experimental results demonstrated the desired performance of BMCs and PFMCs under cyclic shear and axial actions. BMCs showed high-energy dissipation capability and displacement capacity. PFMCs represented high bearing capacity with sufficient lateral strength and energy dissipation capability. Although there was no Mullin effect on the PFMCs response subjected to cyclic shear loading, it was observed on the response of PFMCS under cyclic axial effect. Monotonic and unidirectional cyclic tests of tension, planar shear, and compression were conducted on the rubber pieces to simulate the rubber blocks at PFMCs, as well. Finite element models of BMCs and PFMCs were developed to grasp comprehensively the hysteretic behaviour. The validated model was established and the modeling techniques were described in detail.