Multi-modal seismic control design for multi-storey buildings using cross-layer installed cable-bracing inerter systems: Part 1 theoretical treatment

Abstract

Many attempts have been made to improve the performance of buildings subjected to ground motions with a novel mechanic element, known as an inerter, thereby giving buildings more stability. Recently, a characteristic of the inerter system on controlling the target mode, called the target mode control effect, has been discovered. Considering the prospects of target mode control effect on controlling those buildings affected by multi-modal responses, in this study, cross-layer installed cable-bracing inerter systems (CICBISs) will be used for the multi-modal seismic control. For releasing the end torsion constraints demand of the ball-screw inerter and simplifying the CICBIS's realization, a self-balanced inerter is proposed. A multi-modal seismic control design strategy is proposed to determine the optimal parameters of CICBISs. The equivalent mass with a physical meaning of the multi-storey building with a CICBIS is proposed to quantify the control efficiency of the CICBIS's placement and determine the installation placement of CICBISs directly. A 20-story benchmark building is used to validate the design strategy. The results show that the CICBISs tuned to multi-modes through applying the proposed design strategy can simultaneously focus on controlling multiple target modes. Moreover, it is proved that under the same constraint on each device's control force, the designed CICBISs obtain a higher efficiency on suppressing seismic responses than those CICBISs for single-modal seismic control we proposed in the past and cross-three-layer installed tuned viscous mass dampers. Further sections of the study, including device tests on a self-balanced inerter's prototype and shake table tests on corresponding CIBCIS, will be offered in the following companion paper: Part 2 Experimental treatment.