Indonesia has rich architectural culture of wooden buildings even now. By focusing on one of the most unique and outstanding cultural heritage areas, architectural structural survey of the groups of traditional wooden houses in South Nias, Indonesia, was conducted for their conservation from a structural engineering point of view.
1. Structure of the traditional wooden buildings of which design was originated from ships was characterized. It consisted of three structural parts, the lower structure of columns and braces under the elevated floor, the box structure for living space and the roof frame structure. The joints were categorized into 4 types. As fundamental knowledge, the mechanical properties of woods used for the structures were evaluated.
2. To study seismic safety of the wooden houses that structurally survived against recent devastating earthquakes, microtremore measurements were performed, which revealed their fundamental dynamic properties. Furthermore, seismic response analysis of groups of the houses, by employing the simplified model, demonstrated the effect of the coupling effect in reduction of the response.
3. As results of deterioration and deformation survey of the structural materials, the serious damage due to termite and decay were found. On the basis of the survey, restoration plan was discussed for conservation. To know the environmental effect of roofing materials, Sagoyasshi leaves and GI sheets, on the deterioration, temperature and humidity monitoring was carried out in the roof structures of both roofing materials.