大垂壁を有する伝統木造建物の耐力および崩壊形の簡易推定式の提案

The 1995 Hyogoken-Nanbu earthquake and the 2016 Kumamoto earthquake caused great damage to timber houses such as collapse. On the other hand, there are a lot of traditional timber buildings in Japan as the places for daily life and the cultural townscapes. The mechanical characteristics of these traditional timber buildings are not understood enough. Therefore, it is urgently necessary for the traditional timber buildings to construct reasonable and practical seismic evaluation methods.The planes with “large hanging walls” which consist of columns, tall hanging walls and large section beams called Sashigamoi in Japanese were founded in many traditional timber buildings. However, the plane with large hanging walls had not been focused in previous other study and the mechanical characteristics had not been investigated. Therefore, authors have performed the static loading tests of the full scale traditional timber planes with large hanging walls and analyzed the mechanical characteristics in detail1), 2). As the result, the collapse mode of the plane is closely related to the deformation performance in the plane with large hanging walls. Therefore, it is very important to identify the collapse mode of the planes with large hanging walls in evaluation of the deformation capacity of the planes. However, the collapse mode of the plane is not judged by the current method of seismic performance evaluation on structures with hanging walls3), 4).From the above, we propose a simple seismic performance evaluation method to estimate strength and collapse mode of a plane with large hanging walls in traditional timber buildings in this paper. First, a simple estimation equation of strength and collapse mode of a plane with large hanging walls is proposed. The proposed equation is based on addition of strength of columns and walls. Next, the static loading tests of the new specimens with large hanging walls and walls in the 1st story were conducted in addition to the past specimens with large hanging walls1), 2). Finally, the proposed equation is demonstrated by the test results of the specimens with large hanging walls.The major characteristics of the proposed equation are a) Consideration of flexural capacity deterioration of column at the beam-to-column joint, and b) Collapse mode judgement of plane.a) The columns of planes with large hanging walls tend to break at the tensile stress half of the flexural strength when bent with the tension side of the column inserted