Seismic Testing and Analysis of Rocking Motions of Japanese Post-and-Beam Construction

From our investigation of the experimental seismic response of post-and-beam wooden buildings with different column joints, we developed a nonlinear three-dimensional distinct element model that is capable of time-history response analysis. This model succeeded in predicting the seismic response of the column-base, such as rocking behavior, which has been difficult. Four types of full-scale post-and-beam wooden structures with various column-base systems were tested on a shaking table with three ground-motion sequences for each type of structure, and their response and performance were investigated. By comparing the model’s predictions with the test results, we confirmed the rocking–tracking accuracy of the analysis program. The numerical model was reasonably able to keep pace with the measured experimental response in terms of load-deformation curves, following uplifts and pull-out behavior as observed at the column bottoms in the shake-table tests. The model was also able to predict maximum response acceleration and global interstory drift within 10% accuracy on average. Considering the large uncertainties associated with seismic-collapse predictions, such as complicated nonlinear behavior in frames and joints, these results encourage researchers and designers to understand how these structures respond to earthquakes and how to analyze these structures.