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Abstract:Large-scale shake table tests were conducted at E-Defense, Japan, to examine the 4 dynamic response of a steel concentrically braced frame. The specimen was a single-bay, single-5 story frame with a pair of square-HSS braces placed in a chevron arrangement. The gusset plates 6 connecting the brace to the framing elements were provided with an elliptic fold line to 7 accommodate out-of-plane rotation of the brace in compression. The specimen was subjected 8 repeatedly to a unidirectional ground motion with increasing magnitude until the braces buckled 9 and eventually fractured. The bracing connections performed as intended; the gusset plates 10 folded out-of-plane and no crack was observed in the gusset plate or in the critical welds. 11Consequently, the test results demonstrated excellent performance of the bracing connections. 12Elastic deformation of the beam prevented the braces from developing their full tensile strength. 13Yielding in the middle of the beam, which was predicted by monotonic loading analysis, did not 14 occur. The specimen response was reproduced by a numerical model using fiber elements. This 15 model was able to predict the occurrence of brace buckling and fracture and thereby, accurately 16 trace the dynamic behavior of the frame. 17

Realistic 3D-shake table tests using E-Defense were conducted for full-scale 5-story building specimens with/without dampers to evaluate seismic performance, using ground motions of scales ranging from minor to catastrophic levels. The building was tested repeatedly, inserting and replacing each of 4 damper types. This paper focuses on the second test conducted with bilinear oil dampers. It discusses damper and building specimen, testing and table control methods, validations of test results, various characteristics and control effects of the oil dampers.

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