wooden framed structure
the 2001Geiyo earthquake
This research aims to investigate the relationship between the amount of bearing-wall in an earthquake diagnosis evaluation, the fundamental natural frequency based on the micro-tremor measurement and the actual earthquake damage to conventional wooden-framed houses in Japan. The micro-tremor measurements are widely taken to survey the earthquake damage to wooden houses and the site ground condition. However, a close relationship between the earthquake damage, the amount of bearing-wall of wooden house, and the micro-tremor property is not established. The wall-fulfillment ratio shows an amount of existing bearing-wall with an effective length against the wall required by the Building Code. The diagnosis grade-point for superstructure of wooden house corresponds to the wall-fulfillment ratio, that is, the safety factor of the load-carrying capacity against the external force such as an earthquake or a wind. It is said that, when the grade-point in the evaluation falls to 1.0-0.7, earthquake damage may occur and, when the grade-point is less than 0.7, the collapsing possibility is very high under a severe earthquake.