Effectiveness of a truss-inertial mass damper-core structure system for seismic control of atrium buildings

Large atrium designs are prevalent in most urban areas, including those situated in earthquake-prone regions. To improve the seismic safety of atrium-type buildings, this paper introduces a truss-inertial mass damper-core structure (T-IMD-C) system to establish a novel energy dissipation pathway within the atrium space. The system includes an overhanging cantilever truss connecting the building roof to a core structure built inside the atrium, with inertial mass dampers (IMDs) installed between the truss and core structure to dissipate input seismic energy. The effectiveness of the T-IMD-C system is evaluated through a case study of an eight-story nonlinear building, and a multi-objective optimization approach is proposed for the system to identify the optimal IMD parameters for conflicting objectives, e.g., minimization of structural interstory drift and absolute story acceleration, under multiple seismic inputs. Results indicate that an optimally designed T-IMD-C system effectively mitigates a range of key structural response indices under diverse seismic excitations. Moreover, within the examined range of velocity exponents, higher exponent values generally improve the optimal story acceleration performance for a given effective stiffness of the truss and core structure. Results also reveal that the effectiveness of the T-IMD-C system does not increase consistently with effective stiffness; excessive rigidity in truss and core structures can degrade its optimal performance.