Seismic mitigation performance of structures with viscous dampers under near-fault pulse-type earthquakes

Abstract

This study is aimed at clarifying the seismic mitigation performance of structures with fluid viscous dampers (FVDs) as a function of the characteristics of the near-fault pulse-type (NP) ground motion and the structural dynamic properties. For this purpose, the response spectra and energy response of single-degree-of-freedom (SDOF) structures with FVDs subjected to 20 NP ground motions with different pulse periods Tp are discussed. The seismic response and energy dissipation distribution of multi-degree-of-freedom (MDOF) structures with FVDs are also investigated and compared with those of SDOF structures. The results revealed that although the presence of FVDs produces significant improvements in the seismic response of the structures, the structure may still experience large plastic deformation, which always occurs when T/Tp is less than ‘1’ and T1/Tp is greater than ‘1’, T and T1 being pre-earthquake and post-earthquake structural periods. For short period structures (multi-storey) with FVDs, the plastic deformation can be further slightly reduced by making T/Tp and T1/Tp less than ‘1’ at the same time, so that the structure can be basically kept within the elastic range. However, the intermediate and long period structures (mid-rise and high-rise) with FVDs are more likely to experience large plastic deformation when T/Tp is less than ‘1’, and the floor shear forces may be slightly reduced or even obviously amplified. Furthermore, the current research findings on SDOF structures with FVDs may not be extended directly to MDOF structures with FVDs due to the more complex dynamic properties of MDOF structures.