Verification of seismic performances of wooden shear walls by pseudodynamic lateral loading tests

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Pseudodynamic lateral loading tests were conducted on the conventional wooden shear walls and the two story structures composed of these shear walls. Seismic behavior of shear walls and the influence of the shear stiffness of the second story on the seismic behavior of whole the structure were investigated. Shear walls had 3000mm in length and 3000mm in height, and two story structures had 3000mm width, 3000mm depth and 6000mm height. Seven and a half millimeters thick plywood was nailed on one face of the structure with N50 nails at the intervals of 150mm. At the behind frame, no lateral resisting elements were applied, and steel braces of 16mm diameters were attached on the perpendicular frames and horizontal frames. Hold-down connections were applied at the fool of the first story to prevent the up-lift of the posts. Five types of specimens consisting of shear walls with window, door and slit type openings on the first and second stories were prepared and the lateral loads were applied step-by-step at the top of the first and the second stories by simulating the seismic response based on the NS components of 1940 El Centro accerelogram scaled to 0.4G. In each specimen, 2.5t of masses were assumed both on the first and the second stories. The displacement responses of the first and second stories by the pseudodynamic tests were compared with the results of the time-history earthquake response analysis. The simulation with two lumped masses predicted quite well the response of the first story, but tended to underestimate that of the second story. However FE model predicted quite well the responses of both the first and the second stories, and it was shown that such a sophisticated FE model predicts the seismic behavior of timber structures better than the lumped mass model.