Improving brace seismic performance using novel grid ring damper with augmented composite effect

ABSTRACT This study focused on the seismic performance enhancement of brace members with a novel three-dimensional grid ring damper (GRD), namely the GRD-brace. A series of cyclic load tests on brace members with various ring combinations were conducted. Effective analytical expressions for GRD yield strength evaluation were presented and validated using the test results. Significant gain in GRD-brace yield strength enhancement due to composite effect was achieved, i.e., at least 50% higher than the sum of the strengths of the component in-plane and out-of-plane rings. Adequate accuracy in GRD yield strength evaluation between the analytical and experimental results was obtained. The mean and error propagation for the difference between test and analytical results were 2.29% and 0.74%, respectively, with a standard deviation of 1.36%, at 95% confidence interval, thus validating the effectiveness of the proposed analytical expressions. Significant gain in GRD-brace energy dissipation, approximately 1.77 times the sum of the comprising in-plane and out-of-plane rings, due to effective belt confinements assured design resilience. Effective equivalent viscous damping, approximately 31–44% at 5% story drift, was achieved. The simultaneous achievements in strength enhancement, energy dissipation amplification and equivalent viscous damping sustainment validated the GRD-brace applicability to the structural seismic performance improvement.