Design, testing and implementation of TADAS devices in three RC buildings with shear walls and coupling beams

Abstract

A Triangular Added Damping and Stiffness (TADAS) device is an economic energy dissipation solution to improve the earthquake performance of flexible buildings. TADAS devices have a very stable force displacement constitutive relationship and a high capability of energy dissipation. This research proposes the use of TADAS dampers in coupling beams or lintels between reinforced concrete (RC) shear walls. Coupling beams are typical of RC shear wall buildings with flat slabs and staircase and elevator shear wall cores. The proposed solution integrates into the structure without a relevant impact on the architecture, a significant advantage over other energy dissipation solutions. In this article, three different building applications with TADAS devices are presented. Numerical simulations for these buildings show that drift, displacement, and base shear reductions typically range between 10% and 30%. An effective TADAS design balances stiffness, energy dissipation, and fatigue life of the device under cyclic plastic deformations. Fatigue life for mild steel was determined experimentally and the TADAS devices were designed with a simple model validated by testing of single triangular plates. As expected for rate independent plasticity, tests at different frequencies showed negligible performance variations with deformation velocity. Several TADAS prototypes were cyclically tested and their results are reported in this article. In an effort to analyze the performance and stiffness of the connection between the damper and RC beam, the prototype tests include a section of the capacity-designed concrete beam with the device under simulated as-built conditions. The final design also allows replacing the damper, if needed, after a strong earthquake, and considers an installation procedure that minimizes slip in the connection to the concrete beam.