A comparative study on hysteretic characteristics of austenitic stainless steel and carbon steel slit dampers under cyclic loading

Abstract

Steel slit dampers were designed and fabricated for earthquake-resistant structures using austenitic stainless steel STS304 (ASTM type 304), and carbon steel SS275 (ASTM A36). Monotonic loading and cyclic loading tests were conducted for the materials and steel slit dampers. Monotonic material test results indicated that the tensile strength and elongation of STS304 material were superior to those of SS275. The repeated tests showed that the STS304 steel damper subjected to constant amplitude and incremental amplitude cyclic loading exhibited higher strength ratios and energy dissipation capacity than the SS275 damper until ultimate strength step and 30 mm displacement (story drift) on the skeleton curve of the stainless steel damper after yielding. However, the austenitic stainless steel (STS304) dampers exhibited brittle behavior under cyclic loading due to transformation induced plasticity (TRIP). The total number of cycles at the time of tensile fracture and compressive buckling occurrence was smaller than that of the carbon steel damper except for some specimens with short constant amplitude loading protocol, and thus the total energy dissipation capacity of austenitic stainless steel damper was also found to be on average 95% of that of the carbon steel damper. On the other hand, within the specified low cycle number of loading protocol and allowable story drift of retrofitted building, austenitic stainless steel STS304 slit damper possessed the excellent seismic performance. Finally, the predicted yield strength of the damper was compared with test yield strength and the effect of the cyclic plastic hardening on the yield strength of steel slit damper was also discussed.