FUNDAMENTAL STUDY ON SEISMIC RETROFIT METHOD FOR OLD WOODEN HOUSES USING TIE RODS ANCHORED IN GROUND

Abstract

Lessons learned from the past earthquakes told us the importance of developing seismic performances and retrofitting of wooden houses. Especially for old wooden houses, new technologies which realize not only low cost but also easy installations are needed. In this study, a seismic retrofit method for old wooden houses using tie rods anchored in ground is proposed. The tie rods have helical wing on the edge and work as a small screwed pile. First, penetration tests were carried out to verify a workability of the tie rods. The tie rods were able to be easily installed to ground. More than 1 week later, it was verified that the tie rods were able to resist the tensile forces from 5kN to 25kN from pull-out tests. Finally, evaluation method for tensile strength of the tie rods was established based on simple mechanism and soil investigations from Swedish sounding method.