Cyclic Response of Buckling-Restrained Stainless Steel Energy Dissipating Bars. I: Experimental Investigations

Abstract

The seismic performance of structures could be enhanced by the inclusion of supplemental components that dissipate the earthquake-induced energy. This is especially crucial for rocking structures that possess low energy dissipation properties due to their damage avoidance mechanism. Amongst variously developed yielding-type energy dissipaters (EDs), buckling-restrained energy dissipating carbon steel bars have received considerable attention as they make the most use of the inherent energy dissipation of steel and are easy to fabricate. However, maintenance, repair costs, and performance disruptions owing to corrosive environments have been mostly disregarded in past investigations. Employing stainless steel can be a viable solution to overcome such issues. The work described in this two-part study sheds light on various aspects of the buckling-restrained stainless steel EDs through experimental and finite element (FE) investigations. The mechanical properties of type 304L stainless steel including uniaxial monotonic response, strain sensitivity, and cyclic hardening are characterized. It is shown that the material possesses high ductility along with substantial hardening characteristics. In the first phase of testing, energy dissipating bars with different fuse diameters and lengths are designed. Load and strain capacities and bar-tube interactions of the buckling-restrained energy dissipation device are studied through quasi-static tests. In the second phase of testing, various EDs are designed, fabricated with stainless and mild steel, and tested under quasi-static loading to validate the findings of the FE investigations. The test results demonstrate a stable hysteresis response of the buckling-restrained stainless steel EDs with a cyclic average strain capacity of 10%. The FE modelling procedure, calibration, and parametric studies are presented in the companion paper as Part II.