Seismic Performance Evaluation of Traditional Japanese Wooden Houses with Outer-Frame Reinforcement

The shaking table tests were conducted at the E-Defense of NIED in Japan in 2022, using a full-scale wooden test specimen reflecting a two-story typical traditional Japanese wooden house to investigate the performance of dampers connecting to the outer frames. A reinforced concrete (RC) wall positioned parallel to the specimen’s exterior walls was used for this aim. Detachable oil dampers were installed between the specimen and the top of the RC walls. Four combinations of experimental variables were verified for a single test specimen, involving variations in the rigidity of the horizontal plane on the second-floor level and in the installation of the dampers. The BCJ-L2 wave, a design-specified artificial earthquake equivalent to Level 2 in Japanese design code, was used for input seismic motion. Random wave excitation was also applied at the beginning and end of each specimen’s condition corresponding to the experimental variables. The shaking-table test results showed the response reduction effect at the structural frame line where the oil dampers were connected to the outer frame. The damage progress of the test specimen due to the excitation history was also confirmed from the frequency response analysis for the shaking test results. Moreover, the experimental results were verified through numerical model analysis. The numerical model was prepared as the lamped-mass system. The numerical study considered the influences of multiple inputs of the seismic motions because the reproducibility of the numerical analysis was degraded due to the damage caused by the past large excitation level in the tests. As a result, the numerical analysis results moderately reproduced the experimental responses.