Optimal Seismic Design of Multi-floor Isolation and Viscous Dampers Using 2D Models of Irregular Shear Frame Buildings

Earthquakes threaten buildings, causing humanitarian and economic crises. Conventional earthquake resistance designs allow structural damage to absorb earthquake energy ignoring financial losses that persist from building damage. The Base Isolation System has been developed to promote damage-free seismic protection. When applicable, Base Isolation System ensure operational facilities during earthquakes with no visible deformations. This is done by limiting seismic energy flow using flexible isolators that shift the structure's period away from dominant seismic periods. Acceleration decreases, and relative displacement increases but is concentrated at the base level. Multi-Floor Isolation (MFI) aims to reduce isolation level drift and costs, making it feasible for medium- to high-rise structures. However, efficient MFI design is unpredictable and depends on many factors, including the locations of the isolation levels and dampers, their properties, and the structural elements’ stiffness. Therefore, a formulation of an optimization problem is needed. Current optimization methodologies for MFI structures are limited and computationally demanding. This research proposes an efficient gradient-based optimization approach for enhancing the seismic response of a new irregular 2D shear frame design containing MFI and dampers. The developed methodology optimizes the vertical distribution of the isolation layers and dampers and their properties. Results of an irregular sixteen-story concrete shear frame are shown.