Damage to Buildings Caused by the 1999 Chi-Chi, Taiwan Earthquake and Earthquake Response Analyses Using Recorded Strong Ground Motions

Abstract

The Chi-Chi, Taiwan earthquake, which occurred on 21 September, 1999, brought about severe damage. In this earthquake, many free field strong ground motion records were obtained in a wide range of areas. Most of the strong ground motions were recorded beside reinforced concrete school buildings with simple shapes. Very useful and valuable data were provided for investigating the relationship between strong ground motions and damage to structures. Damage to buildings caused by the 1999 Chi-Chi earthquake was investigated and earthquake response analyses were made for recorded strong ground motions. The relation between actual damage to buildings and results of earthquake response analyses was examined. The results of the damage investigation show that severe damage was found at Chungliao, 5km north-west of the epicenter, and Tongshi, Puli, and Kuoshing, 10-20km east of the Chelongpu fault. We found moderate damage in Shikang and Wufong, but around the Chelongpu fault, we did not find severe damage except at locations very near the fault. These were explained by the results of the earthquake response analyses using single-degree-of-freedom (SDOF) systems. The results of the earthquake response analyses show that from the distributed records, strong ground motion with the most destructive power was recorded at Puli, 20km east of the Chelongpu fault, except one due to local conditions. These findings corresponded to actual damage. However, the destructive power of the record at Puli was smaller than that of the 1995 Hyogoken-Nanbu earthquake. Moreover, it was shown that the elastic response at 1.0 sec is the best index of the destructive power of strong ground motions and that the results of analyses of investigated school buildings approximately correspond to actual damage if the strength of brick walls is considered.1999年台湾集集地震は,甚大な人的および構造物被害をもたらしたが,同時に,広範囲に渡り,非常に多くの強震記録が観測された.記録の多くは,鉄筋コンクリート造学校建物のすぐ脇で観測されており,地震動と構造物の被害の関係を検討するための非常に貴重かつ有用な資料が提供された