Seismic Response of Six-Story Steel Frame Building with Self-Centering Energy-Dissipative (SCED) Braces combined with Linear Viscous Dampers

Autor: Erochko, Jeffrey, Christopoulos, Constantin
Rok vydání: 2014
DOI: 10.4231/d3jh3d32p
Popis: The self-centering energy-dissipative (SCED) brace is an innovative cross-bracing system that eliminates residual building deformations after seismic events and prevents the progressive drifting that other inelastic systems are prone to experience under long-duration ground motions. Previous numerical and experimental shake table studies have been conducted to evaluate the dynamic behaviour of these braces in multi-storey building structures. All of this previous work has focused on the use of friction dampers as the primary energy-dissipating element within the SCED brace. These previous studies found that buildings with friction-damped SCED braces often experience large story accelerations. This study expands upon the previous work by using an existing six-storey building design from one of those studies to determine whether the addition of viscous dampers to the SCED-braced frame can efficiently reduce the accelerations while providing similar or better drift and base shear response. Two main design cases were studied: one with viscous damping only and one where viscous damping was combined with the friction damping within the SCED brace. Realistic SCED braces were designed and their hysteretic behaviour was evaluated using a specially-designed computer program. The viscous damping constant at each story was calculated by determining the equivalent damping necessary to match the energy dissipation provided by a SCED brace with full friction damping at a design drift and modal frequency. The resulting hysteretic behaviour of the structure was then modelled using the nonlinear structural analysis package OpenSees to determine the dynamic response of the structures. The best dynamic response was achieved by using 50% of the full SCED brace friction damping combined with viscous damping equivalent to the remaining 50% of the friction damping evaluated at the first modal frequency. This design resulted in a modest 15% increase in the base shear but it experienced significant performance improvements, decreasing accelerations by 30% and drifts by 20%.
Databáze: OpenAIRE