Estimation of hysteretic energy distribution for energy-based design of structures equipped with dampers

Abstract

Distribution of hysteretic energy along the stories of the building structures is a challenging topic in the energy-based design methods as the key design parameter. This paper aims to determine the vertical distribution of seismic hysteretic energy in the buildings equipped with hysteretic dampers required for the development of reliable energy-based design methods for such complex systems. In this regard, about 250 steel frame structures, 2 to 14 stories in height and equipped with triangular-plate added damping and stiffness (TADAS) dampers are studied. To exploit the maximum energy dissipation capacity of dampers, the frames are designed to achieve a uniform distribution of ductility demands in all stories. The effects of key design parameters such as target ductility capacity, frame-to-damper stiffness ratio, and brace-to-damper stiffness ratio on the vertical distribution of energy are investigated. The results indicate that in the frame structures equipped with hysteretic dampers, if the ductility demands are uniformly distributed along the stories, the energy distribution in the stories can be considered similar to the distribution of story shear forces with very good consistency. It is also shown that the code-proposed linear and power equations adequately estimate the distribution of story shear forces, and hence, can be used to predict the vertical distribution of hysteretic energy in such structures required for energy-based seismic design methods.