Uniform structural deformation oriented viscoelastic damper design and seismic performance enhancements estimation

Abstract

This study proposes a straightforward design method for supplemental viscoelastic dampers (VEDs) to achieve a uniform interstory drift ratio (IDR) distribution. By accounting for the IDR uniformization, the method not only enhances seismic performance but also improves the accuracy of estimating the seismic intensity required for the target performance status. Existing design methods often rely on iterative procedures or neglect IDR distribution changes, leading to inaccurate seismic response assessment and damper design parameters. This study introduces two key innovations: (1) the design method includes the effects of higher-order structural vibration modes and seismic motion characteristics; (2) the damper design and performance estimation methods are simple, direct, and non-iterative, facilitating rational damper planning prior to detailed design optimization. The damper stiffness at each story is designed to match the distribution of story shear capacity with that of story seismic shear, while the damping coefficients are determined from the target supplemental equivalent damping ratio. The proposed design and estimation methods are verified through time-history analyses of multi-degree-of-freedom (MDOF) models under ground motions with varying spectral characteristics. As structural modal periods and ground motion characteristic period increase, especially for the bare structures with highly non-uniform IDR distributions, the method effectively improves IDR uniformity and yields more accurate estimates of the seismic intensity required for target performance. Analyses further demonstrate that enhancing IDR uniformity could evidently reduce maximum IDR with lower supplemental damping demand.