Development of design rules for steel structures subjected to natural fires in the large compartments

Directorate-General For Research And Innovation European Commission

Description

Industrial research and development

Sujets

• Sciences et techniques

Informations

• Publié par: DIRECTORATE-GENERAL-FOR-RESEARCH-AND-INNOVATION-EUROPEAN-COMMISSION
• Nombre de lectures: 17
• Langue: English
• Poids de l'ouvrage: 5 Mo

Extrait

EURO PEAN
COMMISSION
SCIENCE
RESEARCH
DEVELOPMENT
technical steel research
Properties and in-service performance
Development of design
rules for steel
structures subjected
to natural fires in large
compartments
h
Report
EUR 18868 EN STEEL RESEARCH EUROPEAN COMMISSION
Edith CRESSON, Member of the Commission
responsible for research, innovation, education, training and youth
DG Xll/C.l — Competitive and sustainable growth 1 — Materials
Contact: ECSC Steel publications
Address: European Commission, me de la Loi/Wetstraat 200 (MO 75 1/16),
B-1049 Brussels — Fax [phone]; e-mail: [e-mail] European Commission
technical steel research
Properties and in-service performance
Development of design rules
for steel structures subjected to natural fires
in large compartments
J.-B. Schleich, L.-G. Cajot, M. Pierre, M. Brasseur
ProfilARBED
L-4009 Esch-sur-Alzette
J.-M. Franssen
Université de Liège
Service Ponts et Sharpentes Institut Génie Civil
Quai Banning 6
B-4000 Liège
J. Kruppa, D. Joyeux
CTICM
Domaine de Satit Paul
BP64
F-78470 Saint-Rémy-lès-Chevreuse
L Twilt, J. Van Oerle
TNO
Lange Kleiweg 5
Rijswijk
2600 AA Delft
Netherlands
G. Aurtenetxe
Labein
Cuesta de Olabeaga, 16
Apartado 1234
E-48013 Bilbao
Contract No 7210-SA/210/317/517/619/932
1 July 1993 to 30 June 1996
Final report
Directorate-General
Science, Research and Development
1999 EUR 18868 EN LEGAL NOTICE
Neither the European Commission nor any person acting on behalf of the Commission
is responsible for the use which might be made of the following information.
A great deal of additional information on the European Union is available on the Internet.
It can be accessed through the Europa server (http://europa.eu.int).
Cataloguing data can be found at the end of this publication.
Luxembourg: Office for Official Publications of the European Communities, 1999
ISBN 92-828-7168-1
© European Communities, 1999
Reproduction is authorised provided the source is acknowledged.
Printed in Luxembourg
PRINTED ON WHITE CHLORINE-FREE PAPER DEVELOPMENT OF DESIGN RULES FOR STEEL STRUCTURES
SUBJECTED TO NATURAL FIRES IN LARGE COMPARTMENTS
C.E.C. AgreementN° 7210-SA/210,317,517,619,932
FINAL REPORT
RPS Report n° 26
SUMMARY
The aim of this research is to point out that, in view of the fire conditions for large
compartments, the present fire regulations are too severe and to define new
requirements which correspond in a better way to the real fire effect. These new s should be expressed in terms of fire load [ MJ/m2], fire size [ m2] and
Rate of Heat Release [kW]. The procedure developed in the scope of this research
allows indeed to predict that a structure can survive the required fire defined by its
size and its Rate of Heat Release. The ISO requirement F30, F60, F90, F120
should be replaced by the requirement "No failure at all", which demonstrates
an increase of SAFETY.
A procedure has been developed to check whether the fire remains localized and to
calculate the temperature field in a steel structure in that case.
This procedure implies first a calculation of the air temperature based on the
assumption of an upper hot layer, and a lower cold layer. A simplified method and
several 2 zone models have been analysed. An important parameter of a 2 zone
calculation is the rate of Air Entrainment which has been studied in detail. In a
second step, the peak of temperatures produced by the localised fire has been
modelised by the Hasemi's method which provides the heat flux distribution. Based
on these heat fluxes, the ENV 1993-1-2 allows to deduce the steel temperature. The
validity of the Eurocode formulae has been checked in case of localised fire by
comparing the calculated temperatures with the temperatures obtained in different
tests.
Knowing this steel temperature field, the mechanical behaviour is analysed by using
the Fire part of Eurocode 3. A new formula has been developed for a column situated
in a 2 Zone environment.
We have developed a new design tool called TEFINAF (TEmperature Field
under NAtural Fire) providing the steel temperature field of floor beams for any
type of localized fire . DEVELOPPEMENT DE REGLES DE DIMENSIONNEMENT
POUR LES STRUCTURES EN ACIER SOUMISES
A DES FEUX NATURELS
DANS LES GRANDS COMPARTIMENTS
Agrément C.C.E. N° 7210-SA/210,317,517,619,932
RAPPORT FINAL
Rapport RPS n° 26
RESUME
Le but de cette recherche est de montrer que, vu les conditions réelles d'incendie dans
les grands compartiments, les réglementations actuellement en vigueur en matière de
résistance au feu sont trop sévères et de définir de nouvelles exigences qui
correspondent mieux à la réalité. Ces nouvelles exigences devraient être exprimées en
termes de charge au feu [MJ/m2], de taille du feu [m2] et de Taux de Chaleur Dégagée
[kW]. La procédure développée dans le cadre de cette recherche permet précisément
d'étudier la stabilité d'une structure soumise à un feu défini par sa taille et son Taux
de Chaleur Dégagée. L'exigence au feu ISO F30, F60, F90, F120 est à remplacer
par l'exigence "Pas de Ruine lors de l'Incendie", ce qui implique un
accroissement de SECURITE.
Une procédure a été développée pour vérifier si le feu reste localisé et pour calculer le
champ de températures dans la structure en acier dans ce cas.
Cette procédure implique tout d'abord un calcul de la température de l'air basé sur
l'hypothèse d'une stratification des gaz en une zone chaude supérieure et froide
inférieure. Une méthode simplifiée et des modèles 2 Zones ont été analysés. Un
paramètre important de cette approche à 2 zones est le taux d'Air Entraîné qui a été
étudié en détail. Ensuite les pics de température provoqués par le feu localisé ont été
modélisés par la méthode d'Hasemi qui fournit la distribution des flux de chaleur. A
partir de ces flux de chaleur, la méthode comprise dans la ENV 1993-1-2 permet de
déduire la température de l'acier. La validité des formules de l'Eurocode 3 a été
vérifiée en cas de feu localisé, en comparant les températures calculées à celles
obtenues lors de différents essais.
Connaissant le champ de températures dans l'acier, le comportement mécanique est
analysé en utilisant la Partie Feu de l'Eurocode 3. Une nouvelle formule a été
développée pour des colonnes situées dans un environnement à 2 Zones.
Nous avons développé un nouvel outil de dimensionnement appelé TEFINAF
(TEmperature Field under NAtural Fire) donnant le champ des températures
dans l'acier des poutrelles de plancher pour tout type de feu localisé ! CONTENTS
SUMMARY 3
RESUME 4
CONTENTS 5
1. INTRODUCTION 7
2. GENERAL GUIDELINES 9
3. DOES THE FIRE REMAIN LOCALIZED OR NOT ? 13
3.1 Fire Definition 75
3.2 Model of the Rate of Air Entrainment and Application Field 7
3.3 Conditions for a Localized Fire 22
3.3.1 Temperature of the Hot Zone
3.3.2 Thickness of the Smoke Layer 2?
4. TEMPERATURE OF STEEL ELEMENTS IN CASE OF
LOCALIZED FIRE 23
4.1 Introduction ¿3
4.2 Background of the Method 23
4.3 Description of the 24
4.4 Application and Verification for the Large Compartment
"Pare de la Villette" 27
4.5 and for Car Fire Tests 31
4.6 Application and Verification for the Large Compartment
"Parc des Expositions " 33
4.7 and for the simulation 3X 36
4.8 Conclusion 37
5. TEMPERATURE FIELD IN THE STRUCTURE 38
5.1 Temperature Field of a Column subjected to a
Two-Zone Environment 38
5.2 Field of a Beam subjected to a Non- Uniform Heating
along its Length 44
5.3 Conclusion 46
5.4 Design Graphs 47 6. THERMO-MECHANICAL BEHA VIOUR:
Column in a Two-Zone Environment 51
f5.7 Introduction 51
6.2 Results 52
7. DESIGN TOOL 65
8. EXAMPLE 70
9. CONCLUSION2
10. NOTATIONS4
11. BIBLIOGRAPHY 11
Annexes
Annex 1 : The different partners with the addresses. 79
Annex lb: Advisory Committee 80
Annex 2: Analyse of the different models of Fire Plume. 81
Annex 3: Design fire according to building Occupancy given by
NBN S21-208-1 13
Annex 4: Rate of Heat Release for storage building 138
Annex 5: Calculation of the temperature and the thickness of
the smoke layer 14
Annex 6: Simulation of the Fire tests of the "Parc des Expositions,
Paris"6
Annex 7: Simulation 3X 185
Annex 8: Fire tests database : Lund database, NIST database 207 1. INTRODUCTION
The present standards concerning the fire resistance are always based on an uniform