Distribution of temperature in steel and composite beams and joints under natural fire

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Distribution of temperature in steel and composite

beams and joints under natural fire

F. Hanus (B.E.S.T. design office) & J.-M. Franssen (Univ. of Liege)

More info on http://hdl.handle.net/2268/66090

Motivation: analysis of connections in cooling phase => calculation of temperatures in steel beam and in joints.

Existing « lumped capacitance » method:

heating t a a a m sh d net d transferre

h

k

A

t

c

V

Q















_,





_,

OK for unprotected steel sections (heating and cooling) OK for protected steel sections (heating)

OK for lower half of a steel beam with a slab on the upper flange Not OK for the upper part of the steel beam with a slab

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New « Heat exchange » method for T in the upper flange. heating t a a a concrete bottom top gas d transferre Q Q Q c V Q Q            _   _, X Y Z

Diamond 2009.a.4 for SAFIR

FILE: IPE300mixte NODES: 1042 ELEMENTS: 894 CONTOUR PLOT TEMPERATURE PLOT TIME: 1800 sec 822.90 800.00 775.00 750.00 725.00 700.00 675.00 650.00 625.00 600.00 575.00 550.00 525.00 500.00 21.90 More info on http://hdl.handle.net/2268/66090

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concrete

Q



Given by an equation obtained from curve fitting  with numerical results

 based on Annex A of EN 1991-1-2 parametric fire curves Contains 2

parameters

During heating During heating and cooling

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IPE300 IPE550

30’ fire

60’ fire

Works also for the temperature of

the upper flange