9.12 경주지진 및 11.15 포항지진의 구조손상 포텐셜 비교연구

서지정보

ㆍ발행기관 : 한국지진공학회 ㆍ수록지정보 : Jorunal of the Earthquake Engineering Society of Korea / 22권 / 3호
ㆍ저자명 : 이철호, 김성용, 박지훈, 김동관, 김태진, 박경훈

목차

A B S T R A C T
1. 서 론
2. 포항지진 계측 가속도기록 분석
3. 동일연성도스펙트럼 및 해외 강진과의 비교
3.1. 입력지진파 분석
3.2. 동일연성도스펙트럼 비교분석
3.3. 손상 포텐셜 비교연구
4. PHA2 관측소 지반의 영향
5. 포항지진에 의한 저층 필로티 구조물의 지진응답 사례해석
6. 결 어
REFERENCES

영어 초록

In this paper, comparative analysis of the 9.12 Gyeongju and 11.15 Pohang earthquakes was conducted in order to provide probable explanations and reasons for the damage observed in the 11.15 Pohang earthquake from both earthquake and structural engineering perspectives. The damage potentials like Arias intensity, effective peak ground acceleration, etc observed in the 11.15 Pohang earthquake were generally weaker than those of the 9.12 Gyeongju earthquake. However, in contrast to the high-frequency dominant nature of the 9.12 Gyeongju earthquake records, the spectral power of PHA2 record observed in the soft soil site was highly concentrated around 2Hz. The base shear around 2 Hz frequency was as high as 40% building weight. This frequency band is very close to the fundamental frequency of the piloti-type buildings severely damaged in the northern part of Pohang. Unfortunately, in addition to inherent vertical irregularity, most of the damaged piloti-type buildings had plan irregularity as well and were non-seismic. All these contributed to the fatal damage. Inelastic dynamic analysis indicated that PHA2 record demands system ductility capacity of 3.5 for a structure with a fundamental period of 0.5 sec and yield base shear strength of 10% building weight. The system ductility level of 3.5 seems very difficult to be achievable in non-seismic brittle piloti-type buildings. The soil profile of the PHA2 site was inversely estimated based on deconvolution technique and trial-error procedure with utilizing available records measured at several rock sites during the 11.15 Pohang earthquake. The soil profile estimated was very typical of soil class D, implying significant soil amplification in the 11.15 Pohang earthquake. The 11.15 Pohang earthquake gave us the expensive lesson that near-collapse damage to irregular and brittle buildings is highly possible when soil is soft and epicenter is close, although the earthquake magnitude is just minor to moderate (M 5+).

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