Seismic qualification of equipment including piping is performed by using floor response spectra (FRS) or in-structure response spectra (ISRS) as the earthquake input at the base of the equipment. The amplitude of the FRS may be noticeably reduced when obtained from coupling analysis because of interaction between the primary structure and the equipment. This paper introduces a method using a modal synthesis approach to generate the FRS in a coupled primary-secondary system that can avoid numerical instabilities or inaccuracies. The FRS were generated by considering the dynamic interaction that can occur at the interface between the supporting structure and the equipment. This study performed a numerical example analysis using a typical nuclear structure to investigate the coupling effect when generating the FRS. The study results show that the coupling analysis dominantly reduces the FRS and yields rational results. The modal synthesis approach is very practical to implement because it requires information on only a small number of dynamic characteristics of the primary and the secondary systems such as frequencies, modal participation factors, and mode shape ordinates at the locations where the FRS needs to be generated.

A B S T R A C T
1. 서 론
2. 구조내부응답스펙트럼해석의 수식화
    2.1 운동방정식
    2.2 비고전적 감쇠
    2.3 변환모드의 해
    2.4 질량비의 정의
3. 수치해석
    3.1 구조 모델
    3.2 입력운동
    3.3 ISRS 생성 위치
    3.4 ISRS의 비교
4. 결 론
REFERENCES

• 조성국(이노스기술(주) 기술연구소) | Cho Sung Gook (Innose Tech Co. Ltd.) Corresponding author
• 아브히나브 굽타(노스캐롤라이나대학 원자력시설구조센터) | Gupta Abhinav (Center for Nuclear Energy Facilities and Structures (CNEFS), NC State University)