A fundamental-period-preserving seismic retrofit methodology for low-rise buildings with supplemental inerters

Abstract

Stiffness retrofit is a very effective technique to increase the seismic capacity of low-rise buildings. However, the shift of the fundamental period might lead to potential adverse effects when considering the spectral content of the ground motions. To address this issue, this paper proposed a fundamental-period-preserving (FPP) retrofit methodology. By augmenting traditional stiffness retrofit techniques with inerters, the fundamental period can be preserved. In addition, the normalized seismic input force and higher mode effects can be reduced. Different retrofit examples were evaluated through a series of nonlinear static and nonlinear dynamic analyses. Different performance objectives, including roof drift, story drift, story acceleration, base shear, and the force generated by inerters were used to demonstrate the effectiveness and the applicability of FPP approach in structure retrofit. The results showed that the FPP approach is an attractive alternative to the seismic retrofit of low-rise buildings.