A new element elimination model to predict fire-induced damage on an underground structure

Soo-Ho* Chang; Soon-Wook Choi; Gyu-Jin Bae; Sung-Youll Ahn

doi:None

All Issue

2008 Vol.10, Issue 4 Next Page

A new element elimination model to predict fire-induced damage on an underground structure 요소제거기법을 적용한 지하구조물의 화재손상 예측모델 개발

31 December 2008. pp. 313-327

PDF XML

Abstract

Thermo-mechanical coupled behavior of an underground structure during a fire accident have not been fully understood yet. Moreover, when such a thermo-mechanical coupled behavior is not considered in numerical analyses based on conventional heat transfer theory, fire-induced damage zone in an underground structure can be considerably underestimated. This study aims to develop a FEM-based numerical technique to simulate the thermo-mechanical coupled behavior of an underground structure in a fire accident. Especially, an element elimination model is newly proposed to simulate fire-induced structural loss together with a convective boundary condition. In the proposed model, an element where the maximum temperature calculated from heat transfer analysis is over a prescribed critical temperature is eliminated. Then, the proposed numerical technique is verified by comparing numerical results with experimental results from real fire model tests. From a series of parametric studies, the key parameters such as critical temperature, element size and temperature-dependent convection coefficients are optimized for the RABT and the RWS fire scenarios.

Keywords

Underground structure

thermo-mechanical coupling analysis

element elimination model

fire-induced damage

화재 발생 시 지하구조물의 열-역학 상호거동이 정확히 고려되지 못하고 있으며, 이로 인해 일반적인 열전달 이론에 근거한 수치해석 시 화재로 인한 구조물의 손상정도가 과소평가될 수 있는 문제점이 있다. 따라서 본 연구에서는 화재 발생 시 지하구조물의 열-역학 상호거동을 모사하기 위한 유한요소 기반의 수치모델을 새롭게 개발하였다. 특히, 화재로 인한 구조물의 단면 손실을 모사하기 위한 요소제거모델을 제안하였고 대류 경계조건을 적용하였다. 이때 요소 내의 최대 온도가 해석 시에 설정한 임계온도 이상이 되면 요소가 제거되도록 설정하였다. 모형 화재시험 결과와 해석 결과를 비교한 변수해석을 통하여, RABT와 RWS 화재 시나리오 조건에 대한 최적의 임계온도, 요소크기, 온도에 따른 대류열전달계수 조건 등을 제시하였다.

키워드

지하구조물

열-역학 연동해석

요소제거모델

화재손상

References

1.장수호, 최순욱, 권종욱, 배규진 (2006), “화재에 의한 터널구조물 시공재료의 손상 평가”, 대한토목학회논문집, 제26권 제3C호, pp. 219-228.

2.장수호, 최순욱, 권종욱, 김상환, 배규진 (2007), “화재 후 터널구조물 시공재료의 역학적 특성변화”, 한국터널공학회논문집, 제9권 제2호, pp. 157-169.

3.日本コンクーリト工學協會 (2002), コンクーリト構造物の火災安全性硏究委員會報告書, pp. 94-112.

4.ACI Committee (1997), Standard method for determining fire resistance of concrete and masonry construction assemblies, Detroit, American Concrete Institute.

5.ASCE/SFPE29 (1999), Standard calculation method for structural fire protection, Reston, VA, American Society of Civil Engineers.

6.EN1992-1-2 Eurocode 2 (2004), Design of concrete structures, Part 1-2: General rules - Structural Fire Design, Brussels, Commission of European Communities.

7.Boström, Lars and Larsen, Claus K. (2006), “Concrete for tunnel linings exposed to severe fire exposure”, Fire Technology, Vol. 42, pp. 351-362.

8.Caner, A., Zlatanic, S. and Munfah, N. (2005), “Structural fire performance of concrete and shotcrete tunnel liners”, Journal of Structural Engineering, Vol. 131, No. 12, pp. 1920-1925.

9.Cook, R. D., Malkus, D. S. and Plesha, M. E. (1989), Concepts and applications of finite element analysis, 3rd ed., John Wiley & Sons, Inc., pp. 474-482.

10.Cioni, P., Pietro, C. and Salvatore, W. (2001), “Assessing fire damage to r.c. element”, Fire Safety Journal, Vol. 36, pp. 181-199.

11.ITA (2004), Guidelines for structural fire resistance for road tunnels, Working Group No. 6 Maintenance and Repair, pp. 21.

12.Kwak, H. Y., Ha, S. J. and Kim, J. K. (2006), “Non- structural cracking in RC walls Part I. Finite element formulation”, Cement and Concrete Research, Vol. 36, pp. 749-760.

13.Khoury, G. A. (2002), “Passive protection against fire”, Tunnels & Tunnelling International, November, pp. 40-42.

14.Khoury, G. A., Majorana, C. E., Pesavento, F. and Schrefler, B. A. (2002), “Modelling of heated concrete”, Magazine of Concrete Research, Vol. 54, No. 2, pp. 77-101.

15.Kodur, V. K. R and Dwaikat, M. (2008), “A numerical model for predicting the fire resistance of reinforced concrete beams”, Cement & Concrete Composites, Vol. 30, pp. 431-443.

16.Logan, D. L. (1992), A first course in the finite element method, 2nd ed., PWS Publishing Company, pp. 471-486.

17.Ono, Koichi and Otsuka, Takayoshi (2006), “Fire design requirement for various tunnel”, Proc. of 32nd ITA - World Tunnel Congress, Seoul, Keynote lecture.

18.PIARC (1999), Fire and Smoke Control in Road Tunnels, PIARC Committee on Road Tunnels, May 1999.

19.Pichler, C., Lackner, R. and Mang, H. A. (2006), “safety assessment of concrete tunnel linings under fire load”, Journal of Structural Engineering, Vol. 132, No. 6, pp. 961-969.

20.Savov, K., Lacker, R. and Mang, H. A. (2005), “Stability assessment of shallow tunnels subjected to fire load”, Fire Safety Journal, Vol. 40, pp. 745-763.

Information

Publisher :Korean Tunneling and Underground Space Association
Publisher(Ko) :한국터널지하공간학회
Journal Title :Journal of Korean Tunnelling and Underground Space Association
Journal Title(Ko) :한국터널지하공간학회 논문집
Volume : 10
No :4
Pages :313-327

Journal of Korean Tunnelling and Underground Space Association ISSN:2233-8292(Print) 2287-4747(Online) 한국터널지하공간학회 논문집

All Issue