Equivalent Single-Degree-of-Freedom Model for the Seismic Fragility Estimation of Pipeline-Supporting Steel Concentrically Braced Frames

Hyun Go; Hyung-Joon Kim

doi:10.7734/COSEIK.2026.39.5.283

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2026 Vol.39, Issue 5 Next Page

Research Paper

Equivalent Single-Degree-of-Freedom Model for the Seismic Fragility Estimation of Pipeline-Supporting Steel Concentrically Braced Frames 파이프랙 철골중심가새골조의 지진취약도 추정을 위한 등가단자유도계 모델

31 October 2026. pp. 283-291

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Abstract

This study proposes an equivalent single-degree-of-freedom (E-SDOF) model for estimating the seismic fragility functions of pipe racks commonly found in petrochemical facilities. Pipe racks are critical industrial systems that support piping networks. Earthquake-induced damage to such structures may result in direct and/or indirect consequences, including fire, explosion, and toxic material leakage. Three-tier and six-tier archetype pipe racks employing steel concentrically braced frames were selected from a database of pipe racks in a domestic petrochemical complex, and detailed nonlinear numerical models were developed. The corresponding E-SDOF models were constructed using the results of the monotonic and cyclic pushover analyses. Piping loads were modeled as external forces distinct from seismic inertia forces. The E-SDOF models reasonably captured the hysteretic behavior, cumulative energy dissipation, and incremental dynamic analysis (IDA) curves obtained from the detailed nonlinear models. The median values of the fragility functions estimated using the E-SDOF models were within ±20% of the IDA-based results for all damage states. These results indicate that the proposed methodology provides a practical alternative to IDA-based fragility assessment of pipe racks.

Keywords

pipe racks

steel concentrically braced frames

equivalent single-degree-of-freedom model

seismic fragility

본 연구에서는 플랜트 내 파이프랙의 지진취약도함수를 효율적으로 추정하기 위한 등가단자유도계(E-SDOF) 기반 방법론을 제안하였다. 파이프랙은 배관을 지지하는 산업시설로서, 지진 시 화재 및 폭발과 같은 2차 피해로 이어질 수 있다. 본 연구에서는 국내 파이프랙 데이터베이스를 바탕으로 표본 파이프랙을 선정하고, 비선형해석모델을 구축하였다. 비선형정적해석 결과를 이용하여 E-SDOF 모델을 수립하였으며, 배관하중은 별도 외력으로 고려하였다. 검증 결과, E-SDOF 모델은 표본 파이프랙의 이력거동 및 증분동적해석 결과를 적절히 재현하였다. 또한, E-SDOF 기반 취약도 중앙값은 ±20% 이내의 오차를 보였다. 따라서 제안된 방법론은 파이프랙의 지진취약도함수를 효율적으로 추정하는 대안이 될 수 있다.

키워드

파이프랙

철골중심가새골조

등가단자유도계

지진취약도

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Information

Publisher :Computational Structural Engineering Institute of Korea
Publisher(Ko) :한국전산구조공학회
Journal Title :Journal of the Computational Structural Engineering Institute of Korea
Journal Title(Ko) :한국전산구조공학회 논문집
Volume : 39
No :5
Pages :283-291
Received Date : 2026-05-21
Revised Date : 2026-05-27
Accepted Date : 2026-07-01
DOI :https://doi.org/10.7734/COSEIK.2026.39.5.283

Journal of the Computational Structural Engineering Institute of Korea ISSN:1229-3059(Print) 2287-2302(Online) 한국전산구조공학회 논문집

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