Plastic Frame Analysis under Fire Conditions
Publication: Journal of Structural Engineering
Volume 127, Issue 3
Abstract
This paper presents the use of plastic analysis methods for the calculation of critical temperature distribution for structures at collapse under fire conditions. The methods are based on the well-known plastic hinge concept using both elastoplastic and upper-bound approaches. The simple concept of plastic load factor for collapse analysis is extended to elevated temperature analysis which leads to the development of the unit load factor method for critical temperature factor calculation. The critical temperature factor is used to indicate the factor of safety for a structure under certain fire scenarios. In this approach, linearly varying distributed loads can be included in the analysis. The upper-bound approach is based on the conventional collapse mechanism calculation method, modified to include the temperature-dependent material properties. It is found that the critical collapse mechanism may become noncritical when temperature changes. A demarcation temperature multiplier is proposed to monitor such a phenomenon. Worked examples for both the elastoplastic and upper-bound approaches are presented.
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References
1.
Armer, G. S. T., and O'Dell, T. ( 1996). “Fire, static, and dynamic tests of building structures.” Proc., 2nd Cardington Conf., E & FN Spon, London.
2.
British Standards Institution (BSI). ( 1990). “The structural use of steelwork in buildings. Code of practice for fire resistant design.” BS 5950: Part 8, London.
3.
Chen, W. F., and Sohal, I. ( 1995). Plastic design and second-order analysis of steel frames, Springer, New York.
4.
Comite International pour le developpement et l'Etude de la construction tubulaire (CIDECT). ( 1994). Design guide for structural hollow section columns exposed to fire, Rheinland, Verlag TUV Rheinland, Koln, Germany.
5.
Cook, R. D., Malkus, D. S., and Plesha, M. E. ( 1989). Concepts and applications of finite-element analysis, 3rd Ed., Wiley, New York.
6.
CTICM. ( 1982). “Methode de prevision par le calcule du comportement au feu des structures en acier.” Construction Metallique, Paris, 19(3), 39–79.
7.
Davies, J. M., and Brown, B. A. ( 1996). Plastic design to BS 5950, The Steel Construction Institute, U.K.
8.
ECCS. ( 1983). “European recommendation for the fire safety of steel structures.” Tech. Com. 3, Elsevier Science, Amsterdam.
9.
Fire Code Reform Centre Limited (FCRCL). ( 1996). “Fire engineering guidelines.” Australia.
10.
Lie, T. T. ( 1992). “Structural fire protection.” Manual and reports on engineering practice No. 78, ASCE, New York.
11.
Liu, T. C. H. ( 1996). “Finite-element modeling of behaviors of steel beams and connections in fire.” J. Constr. Steel Res., 36(3), 181–199.
12.
Morris, W. A., and Kirby, J. A. ( 1997). “Computers and fire-safe structural design.” Proc., Struct. Congr. XV, L. Kempner Jr. and C. B. Brown, eds., Vol. 2, ASCE, New York, 518–522.
13.
Najjar, S. R., and Burgess, I. W. ( 1996). “A nonlinear analysis for three-dimensional steel frames in fire conditions.” Engrg. Struct., 18(1), 77–89.
14.
O'Connor, M. A., and Martin, D. M. ( 1998). “Behavior of a multistory steel-framed building subjected to fire attack.” J. Constr. Steel Res., 46, 1–3.
15.
Patterson, N. L., and Wong, M. B. ( 1997). “Influence of coefficient of thermal expansion on steel frame strength.” Proc., 15th Australasian Conf. on Mech. of Struct. and Mat., 291–296.
16.
Saab, H. A., and Nethercot, D. A. ( 1991). “Modeling steel frame behavior under fire conditions.” Engrg. Struct., 13(Oct.), 371–382.
17.
SBI. ( 1976). “Fire engineering design of steel structures.” Swedish Institute of Steel Construction, Sweden.
18.
Schleich, J. B., Dotreppe, J. C., and Franssen, J. M. ( 1985). “Numerical simulations of fire resistance tests on steel and composite structural elements or frames.” Proc., 1st Int. Symp., Fire Safety Sci., International Association for Fire Safety Science, Boston, 311–323.
19.
Standards Association of Australia (SAA). ( 1990). “Steel structures.” AS 4100, Sydney, Australia.
20.
Toh, W. S., Tan, K. H., and Fung, T. C. (2000). “Compressive resistance of steel columns in fire: Rankine approach.”J. Struct. Engrg., ASCE, 126(3), 398–405.
21.
White, D. W., and Chen, W. F., eds. ( 1993). Plastic hinge-based methods for advanced analysis and design of steel frames: An assessment of the state-of-the-art, Structural Stability Research Council, Bethlehem, Pa.
22.
Wong, M. B. ( 1991). “Direct analytical methods for plastic design.” Australian Civ. Engrg. Trans., CE33(2), 81–86.
23.
Wong, M. B., Ghojel, J. I., and Crozier, D. A. ( 1998). “Temperature-time analysis for steel structures under fire conditions.” Struct. Engrg. and Mech., South Korea, 6(3), 275–289.
24.
Wong, M. B., and Patterson, N. L. ( 1996). “Unit load factor method for limiting temperature analysis of steel frames with elastic buckling failure mode.” Fire Safety J., Amsterdam, 27, 113–122.
Information & Authors
Information
Published In
Journal of Structural Engineering
Volume 127 • Issue 3 • March 2001
Pages: 290 - 295
History
Received: Dec 13, 1999
Published online: Mar 1, 2001
Published in print: Mar 2001
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