Overturning resistance of rocking columns with novel self-centering unilateral viscous damper pulley systems (SUVDPs)

Abstract

Rocking columns possess re-centering capability, but their energy dissipation capacity is limited, which may lead to significant response and even cause overturning under seismic excitation. To deal with such issues, a novel self-centering unilateral viscous damper pulley system (SUVDPS) based on the amplification mechanism of pulleys is here proposed as an effective control device. The SUVDPS consists of two components: an energy dissipation element composed of a spring and a unilateral viscous damper, and an amplification mechanism composed of pulleys and cables. The latter can amplify velocities and displacements of the energy dissipation element, with a considerable boost of energy dissipation. The equations of motion of the structure are first derived by symmetrically arranging the SUVDPS on both sides of the rocking column. Comprehensive parametric analyses are carried out to examine the influence of some key parameters, including amplification factor, damping coefficient, spring properties and size. The effectiveness of the SUVDPS is examined by investigating the overturning acceleration spectrum. Using the South Rangitikei Railway Bridge as a benchmark model, the hysteresis curves of SUVDPS and structural response with different conditions are investigated. The results indicate that SUVDPS has a superior energy dissipation capability. By increasing the amplification factor of the SUVDPS, it is possible for a structure with a small damping coefficient to generate a large control force during small uplift displacements, thereby controlling excessive vibrations and improving its overturning resistance.