Structural Steel Fire Engineering - Aarhusstaff.iha.dk/lc/Steel/litteratur/ECCS- Fire engineering.pdf · Cognos GmbH, Universität of Hannover ... Izmit, Turkey. ECCS ... ECCS - 18

Structural Steel Fire Engineering

ECCS Technical Meeting17-19. September 2008Aalesund, Norway

Louis-Guy CAJOTArcelorMittalResearch & DevelopmentStructural Long Products Esch/Alzette GD-Luxemburg

Structural Steel Fire EngineeringECCS - 18 September 2008 1

Structural fire safety

© Skidmore, Owings & Merrill LLP / dbox Studio

Single storey buildings(f.i. Industrial hall)

multi-storey buildings

Fire safety engineering (Natural fire, behavior of the whole structure, DIFISEK, Secure with steel network, FRACOF

Fire resistance of structure Occupants and firemen safety

single storey buildingsFire resistance of structure Firemen safety

Fire safety engineering (Non progressive collapse, compartmentation, fire walls, …)


Multi-storey buildingsSteel market share in multi-storey buildings

Weak knowledge from engineers and architects of the actual performances of the steel in case of fire, still mainly assessed through knowledge from fire test on single element.Fire Safety Engineering not yet fully considered

One of the reasons explaining the differences: Fire Safety Approach. The present low market share in continental Europe is more particularly due to :

Market share / Multi-storey buildings

0

10

20

30

40

50

60

70

80

UK SE NL FI FR BE-LU DE ES

%

Pote

ntia

l


Classical approach amongst “structural fire safety engineering”methods - Eurocodes 1, 3 and 4

standard fire natural fire

classification fire safety eng.

fire safety eng. fire safety eng.

Prescriptive Performance based


Time [min]0

200

400

600

800

1000

1200

0 30 60

θ [°C]

90 120 180

* does not consider the PRE-FLASHOVER phase* does not depend on FIRE LOAD and VENTILATION

CONDITIONS

ISO ISOISO

ISO ISO

ISO

ISO

ISO

The ISO curve* has to be considered in the WHOLE compartment, even if

the compartment is huge

* never goes DOWN

Classical approach based on ISO-834 heating curve


Unprotected steel structures for fire resistance ≤ 30minutesR30 unprotected steel structures (Overdesign [S355,S460] ; benefit of the connections)

Classical approach - Quick use of the Eurocodes

ArcelorMittal Belval & DifferdangeUniversity of Liège


Steel protection for fire resistance > 30 minutes

Additionnal cost of the protection > 40% of the finished steel cost

0

200

400

600

800

1000

0 30 60 90 120time [min]

tem

pera

ture

[°C

]

15’ 30’ 60’ ISO-curveHE180BHD400x382

HE320A 15mm sprayed material

Classical approach based on ISO-834 heating curve

The protection must be optimized and applied where it is really needed.

ArcelorMittal Belval & DifferdangeUniversity of Liège






The performance based “structural fire safety engineering”approach according to Eurocodes 1, 3 et 4

Fire Safety Engineering + Global Structural Behavior = Fire Development


Fire Engineering approach

Scientific analysis based on :Fire scenarioPhysical parameters influencing the fire development (fireload, ventilation, active fire fighting measures, …)

Standard curve

More controlled safety and more efficient solutions because better targeted

Temperature

Cooling ….

ISO834 standard fire curve

Ignition - Smouldering

Pre- FlashoverPre- Flashover

Heating

Post- Flashover1000-1200°C

Post- Flashover1000-1200°C

Natural fire curve

Time

FlashoverFlashover


Fire Engineering approach

Fire safety concept evaluation based on natural fire.Required data for the fire development calculation methods (fire load [MJ/m²], fire spread, rate of heat release [kW/m²]).Definition of model scenario for usual buildings (offices, schools, shops,…).Simulation of the behaviour of the structure submitted to the different fire scenarii and to the static loads.

European research in the field of the fire engineering achieved between 1994 → 2006 allows to develop Fire Engineering approach including :

Existing regulations and standards based on standard fire.Habits and perception of the professionals of construction.Different regulations depending on the countries and even on the regions.Low expertise of engineers, architects in that domain.Lack of training in that domain.No userfriendly calculation tools.

The implementation of the research results met

solved by :The natural fire was introduced in the Eurocodes, particularly Eurocode 1 - Fire Part.The fire engineering has been dealt with in decree and regulations in different european countries .Userfriendly calculation tools were developed (Ozone), and put on the site www.arcelormittal.com/sectionsTrainings were, and are organized (DIFISEK).A network of competent and qualified engineering offices in the field of fire engineering was developed (SECURE with STEEL).

the following difficulties :


OzoneNatural Fire calculation according to EC1 Fire Part


θHot

θCold

OzoneNatural Fire calculation according to EC1 Fire Part


’Fire Safety Engineering’ application to buildingsin G-D of LuxembourgDIssemination of FIre Safety Engineering Knowledge: DIFISEK

RFCS dissemination project

Austria02 oct 08

Belgium22 oct 08 Germany

14 nov 08

Spain12 nov 08

France01 july 08

UK20 sept 08

Czech Rep24 sept 08

Italy03 dec 08

Portugal05 dec 08

Poland28 nov 08

Swedennov 08

Hungary29 oct 08

Romania14 nov 08

Lithuania05 dec 08

Greecenov 08

Slovenia15 oct 08

Estonianov 08Treated topics

Part 1: Thermal & Mechanical ActionsPart 2: Thermal ResponsePart 3: Mechanical Response of

Structures in Fire Part 4: Software for Fire DesignPart 5-1: Worked Examples Part 5-2: Illustration of Completed

Projects

Available tools for further dissemination

All Presentations and Syllabus in PDF for the 5 parts (17 languages)

http://www.difisek.eu/


SECURE with STEEL in Europe25 European engineering offices specialized in

Fire Engineering assisted by 9 universities and/or research centers

Medical Centre - Eich ; G-D Luxembourg

’Fire Safety Engineering’ applicationto buildings in G-D of Luxembourg

ARUP Fire

Austria - Bernard IngenieureBelgium - Greisch, Technum, Steel Information Centre, Delta, University of LiègeCzech Republic - CTU PragueFrance - Arches-Etudes, E2C Atlantique, Terrell InternationalGermany - Lenz Weber Ingenieure, Schmitt Schtumpf Fruhauf & Partner, BFT

Cognos GmbH, Universität of HannoverItaly - Studio di Ingegneria delle StruttureLuxembourg - Schroeder & AssociésPoland - KeonnPortugal - Tal Projecto, GIPAC, University of AveiroSpain - NB35, Idom, LABEINSweden - Swedish National Testing & Research InstituteSwitzerland - MP Ingénieurs, Borgogno Eggenberger + Partner, ETH ZürichThe Netherlands - DGMR, Hamerlinck Advies bureau, Cauberg-Huygens, DHV BVUnited Kingdom - ARUP Fire, University of Edinburgh


The “structural fire safety engineering” approachEurocodes 1, 3 et 4






Test in Cardington (UK)

The structuresurvives

the severenatural fire

(θair > 1200 °C)


FRACOFFire Resistance Assessment of partially protected Composite Floor





FRACOF


Design of test specimen

CORNER

Structure grid of a real building

Adopted steel frame for fire test


Rf = 20 minNakedcentral beams

Protectedsurrounding beams

FRACOF

9m

7m


ISO-834 Curve

Floor exposed to fire below

Loading condition

Uniform loading through 15 sand bags to simulateDead load: 1,25 kN/m²Imposed load: 5,0 kN/m²

Equivalent uniform load3,87 kN/m² ≈ (1,25 + 0,5 x 5)

Partitions ψ1 Imposed Loads

Weight of each sand bag = 1500 kg

Heating condition

FRACOF

0

200

400

600

800

1000

1200

0 30 60

θ [°C]

90 120 180

t [min]

1110

9451006 1049

842


FRACOF TEST about 80 people from Authorities


Test resultsR > 120 minutes

Deformed shape 1040 °C

300 °C

Rebars: 300 °C

0

50

100

150

200

250

300

350

400

450

500

0 90 180 270 360 450 540 630 720 810 900Time [min]

Ver

tical

dis

plac

emen

t [m

m]

45cm

34cm


Fire resistance of secondary beams calculated as single elements

EC4 Fire partCritical temperature = 608 °CFire resistance = 16’

Fire resistance = 20’SAFIR Simulation

Membrane effect highlighted by an academic exampleD

efle

ctio

n [m

]Time [min]

f

65h

f

-1.2

-1

-0.8

-0.6

-0.4

-0.2

00 20 40 60 80 100 120


T Mobile HeadquartersHatfield Hertfordshire

School in

Turkey

Fire Safety Concept : protected main beams,unprotected secondary beams

Fire safety engineering is aimed at adopting a rational scientific approach which ensures that fire resistance/protection is provided where it is needed rather than accepting universal provisions which may over or under estimate the level of risk.

Arda School,Izmit, Turkey


Single storey buildings

High potential of steel in single-storey buildings

Market share / Single-storey buildings

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

UK NL SE FR BE&LU DE FI ES


Real Fires In Industrial Halls - Charleroi

Masonry façade: outside collapse

Steel Façade: inside collapse


• First phase - thermal expansion of heated members:

• Second phase - collapse of the heated beam:

Behaviour of structure in fire


Risk of collapse

Failure modes

– collapse of structure towards outside;– collapse of facades and fire walls towards outside;

Risk of collapse of facade elements towards the outside during the expansion phase

– collapse of an adjacent cold structure – progressive collapse.

Risk of progressive collapse of the load bearing structure


• Design guide– illustrates possible failure modes of industrial halls– proposes methods to avoid them (calculation of displacement and

tensile forces, recommendation for bracing, fire protection of beams next to fire walls and calculation of required fastening force for façade)

• Software “LUCA”– Calculates maximum displacement and tensile forces

Deliverables

Forces : The force that will be obtained in stage of pull must be used to verify the stability of the cold part (force located in the top of the column).

Displacement : The displacements that will be obtained must be used to verify the stability of the interior and exterior walls (façades and Fire Wall)


Fire Safety of Industrial Hall

Software

Dissemination seminarsMadrid - 12 Nov

Brussels - 17 and 21 NovParis - Dec


Fire Safety of Industrial Hall - Fire-break wall

1.

Fire starts 2.

Fire development and fusible connections ensure that the link between wall and heated structure disappears

3.

Fully developed fire and failure of the heated structure.

4.

Decay phase of the fire and no damage at all to the compartment on the other side of the wall.

Fire-Break is a steel fire wall produced and commercialised by ArcelorMittalFrance : AM Distribution France / Europe : AM Dudelange (F. Covella)


Conclusions

Steel structures demonstrate an actual much higher fire safetythan usually appreciated by most players of construction world

Steel structure

Steel structure

>2h of FR>1000°C

Fire safety engineeringDetailed study → Higher safety

Failure modenon-progressive collapseinward failure

Higher safety of firemenductile predictable failurelarge displacement before failuresafe fire wall

Documents

Structural Steel Fire Engineering - Aarhusstaff.iha.dk/lc/Steel/litteratur/ECCS- Fire engineering.pdf · Cognos GmbH, Universität of Hannover ... Izmit, Turkey. ECCS ... ECCS - 18