RELATIONSHIP BETWEEN SEISMIC CAPACITY GRADE AND DAMAGE FOR POST AND BEAM WOODEN STRUCTURES : A study on decision-making tools for promoting aseismic reinforcement of old wooden houses (Part 1)

Abstract

Despite the large possibility of numerous mortalities due to the collapse of old wooden houses in the event of a strong earthquake in Japan, efforts for seismic upgrading are not well in progress. The promotion of the upgrading of old wooden houses is one of the most important measures by which the owners of such houses can recognize the cost-effectiveness of seismic upgrading. The purpose of this study, therefore, is to develop decision-making tools that could be used by owners. This paper discusses the relationships between the seismic capacity grade and the extent of damage to an old post and beam wooden house due to a ground motion with each seismic intensity scale. Results obtained in this paper are presented as follows: 1) The relationships between the seismic capacity grade and damage to a wooden house were developed using a dynamic response analysis with ninety-five non-scaled seismic records. 2) The relationships between seismic capacity grade and damage were found to exhibit considerable variation, especially in the range of large seismic intensity scale. 3) The relationship between the seismic capacity grade and damage calculated by the dynamic response analysis concurs closely with the findings from survey results after actual earthquake disasters. 4) The paper presents a probabilistic performance matrix that considers the large variation observed in the damage to post and beam wooden houses.