Experimental and analytical investigations on new viscoelastic damped joints for seismic mitigation of structures with precast shear walls

摘要

Precast concrete wall has become a crucial part in the architectural industrialization, which is in line with the development trend of the building industry. On the basis of the analysis of relations between the deformation and the energy distribution of the precast concrete walls under major earthquakes, this investigation proposes the idea of a novel viscoelastic damped joint (VDJ) to create the vertical connection between two precast walls. By amplifying the displacements and velocities of the joint, the energy dissipating properties of damping materials can be fully used. The VDJ is suitable for improving the damping efficiency in the stiff shear wall structural systems. Performance tests were performed to study the mechanical properties of the damped joint. And then, a simplified analytical model of the VDJ with different parameters under various deformations and frequencies is presented. The numerical simulation results indicate that the simplified model is capable of capturing the main features of the VDJ. Furthermore, the analytical models on wall to wall connections were set up and incorporated into 2-D numerical models. To better understand the damping performances of the VDJ, three models connected by emulating cast in situ joints, precast hinged joints, and viscoelastic damped joints were prepared by analyzing the time history of the overall structural response. Results show that the VDJs are effective in attenuating seismic response of the precast walls. They worked in the dissipation of approximately 90% of input earthquake energy. The highly efficient damped joints also reduce interstory displacements and upgrade the structural performance of buildings during seismic excitation.