A study on seismic performance of traditional wooden buildings

In the recent trend of reassessment of wooden buildings it has been increasingly desired to build shrines and temples with wood instead of rein forced concrete in steel. However, according to the current method in which the bearing walls are considered as the primary elements for horizontal resistance, there remains many problems to be solved if we try to apply the structural system of traditional wooden buildings to these buildings. in addition, the continuous absence of coordination between those who involved in actual construction like carpenters and those who involved in research of structure has left many problems to be solved. The seismic performance of traditional wooden buildings was surveyed quantitatively. A case study was made on the damage in Kamakura brought by 1923 Kanto Earthquake. First, records and literature about the soil of Kamakura were collected and the thick and soft alluvium layer, were found along the coast and in the inland area. At the same time a research on the damage of wooden buildings in the area was performed through records and literature. The result shows the high damage ratio among wooden buildings and a certain correlation between the damage and the location of the alluvium. Through a questionnaire survey sent to as shrines and temples in the area in addition to references to literature and supplementary hearings, the following conclusions as to what types of buildings were damage ; 1 ) as for types of buildings, the damage ratio of main halls at Buddhist temples was rather high, 2 ) as for roof materials, the heavier materials like thatched roof or tiled roof caused heavy damage, 3 ) as for periods when the building was constructed, not much difference was found, 4) the higher the wall ratio was, the smaller the damage was found, and 5 ) the thicker the alluvium was, the heavier the damage was brought as in the case of wooden houses. There was also found a certain correlation of the damage ratio between houses and shrines and temples. As a result of this survey, there are well organized data sheets of these buildings, which will make it possible for a further study on individual buildings. For the next stage of this study, a structural analysis of these buildings by methods of response analysis will be made.