Fire Safety Engineering for open and closed car parks: C.A...
Transcript of Fire Safety Engineering for open and closed car parks: C.A...
Giuseppe Cefarelli
D.I.ST. – Department of Structural EngineeringUniversity of Naples “Federico II”, Italy
Fire Safety Engineering for open and closed car parks: C.A.S.E. Project for L’Aquila
Training School for Young Researcher
11-14 April 2012, Sliema, Malta
Fire Safety Engineering for open and closed car parks: C.A.S.E. Project for L’Aquilaeng. Giuseppe Cefarelli, [email protected]
Introduction: Fire Safety Engineering
The “Fire Safety Engineering” (FSE) is the application of engineeringprinciples, rules and expert judgement based on a scientificassessment of the fire phenomena, the effects of fire and both thereaction and behaviour of peoples, in order to:
A branch of Fire Safety Engineering is Structural Fire Engineering.
Structural Fire Engineering deals with specific aspects of passive fire protection in terms of analysing the thermal effects of fires on buildings and designing members for adequate load bearing resistance and to control the spread of fire (C. Bailey).
- save life, protect property and preserve the environment and heritage,
- quantify the hazards and risks of fire and its effects,- evaluate analytically the optimum protective and prevention
measures necessary to limit, within prescribed levels, the consequences of fire (ISO/TR 13387-1).
Fire Safety Engineering for open and closed car parks: C.A.S.E. Project for L’Aquilaeng. Giuseppe Cefarelli, [email protected]
FSE: Layout
Modify of the Active and Passive Fire
Protection
Design and Structural Model
Building description: Analysis of the structural characteristics
Choose of the Safety Performance Levels
Choose of the Active and Passive Fire Protection
Fire Model Fire Design Scenario
The model meets the safety levels choose?
Were tested all scenarios?
Static and fire design load calculation
Modify of the size or ty-pology of structural ele-
ments
Or
Thermal and structural analysis (for each fire design scenario)
YES
NO
END
YES
NO
Fire Safety Engineering for open and closed car parks: C.A.S.E. Project for L’Aquilaeng. Giuseppe Cefarelli, [email protected]
Modify of the Active and Passive Fire
Protection
Design and Structural Model
Building description: Analysis of the structural characteristics
Choose of the Safety Performance Levels
Choose of the Active and Passive Fire Protection
Fire Model Fire Design Scenario
The model meets the safety levels choose?
Were tested all scenarios?
Static and fire design load calculation
Modify of the size or ty-pology of structural ele-
ments
Or
Thermal and structural analysis (for each fire design scenario)
YES
NO
END
YES
NO
Case Study: Car Parks of C.A.S.E. Project for L’Aquila
Car Park located at the ground floor
steel column
Concrete slab
Isolationdevice
The “C.A.S.E. Project for L’Aquila” was developed in L’Aquila (province of Abruzzo, Italy), after the seismic event of 06/04/2009, in response to the housing emergency. It was characterised by the construction of several seismically isolated buildings.
Fire Safety Engineering for open and closed car parks: C.A.S.E. Project for L’Aquilaeng. Giuseppe Cefarelli, [email protected]
The structural safety during the fire exposure, in the lack of protective
coatings on steel columns, was evaluated through the application of
performance-based approach
58 m
22 m
uncertainties on the effectiveness
of coatings maintenance
Park Description: Below each isolation interface is located the parking
area for about 34 cars; Each concrete base slab, with thickness 50 cm, is
supported by steel columns (260 cm in height) withintervening seismic isolators;
The size of the plant compartment in garage amountedto 22m × 58m; in fact, the perimeter walls, when present,are offset by 50 cm beyond the vertical projection of theplate isolated;
The circular hollow steel sections have a capital at thetop, which is designed to transfer load from the isolatorunit and to allow the isolator replacement.
CLOSED CAR PARK
OPEN CAR PARK
Italian prescriptive code (D. M. 01/02/1986)
R90
Case Study: Car Parks of C.A.S.E. Project for L’Aquila
Sprayedgypsum
The objective of fire safety design concerns the mechanical resistance and stability, in firesituation, of the primary structural elements in the zone below the seismically isolatedplate.
Fire Safety Engineering for open and closed car parks: C.A.S.E. Project for L’Aquilaeng. Giuseppe Cefarelli, [email protected]
Performace levelA limited damage after the fire exposure.
Modify of the Active and Passive Fire
Protection
Design and Structural Model
Building description: Analysis of the structural characteristics
Choose of the Safety Performance Levels
Choose of the Active and Passive Fire Protection
Fire Model Fire Design Scenario
The model meets the safety levels choose?
Were tested all scenarios?
Static and fire design load calculation
Modify of the size or ty-pology of structural ele-
ments
Or
Thermal and structural analysis (for each fire design scenario)
YES
NO
END
YES
NO
Case Study: Car Parks of C.A.S.E. Project for L’Aquila
The damage is quantified in terms of relative vertical displacements between the top of two adjacent columns: in order to limit the finishing damage in the superstructure, the relative vertical displacement must not exceed the limit value, chosen cautiously equals to L/200 (5.0 ‰), where L is the distance between two adjacent columns (L=6000mm).
Fire Safety Engineering for open and closed car parks: C.A.S.E. Project for L’Aquilaeng. Giuseppe Cefarelli, [email protected]
Protection systemsNo specific protection systems (active and/or passive) are provided.
Modify of the Active and Passive Fire
Protection
Design and Structural Model
Building description: Analysis of the structural characteristics
Choose of the Safety Performance Levels
Choose of the Active and Passive Fire Protection
Fire Model Fire Design Scenario
The model meets the safety levels choose?
Were tested all scenarios?
Static and fire design load calculation
Modify of the size or ty-pology of structural ele-
ments
Or
Thermal and structural analysis (for each fire design scenario)
YES
NO
END
YES
NO
Case Study: Car Parks of C.A.S.E. Project for L’Aquila
Fire Safety Engineering for open and closed car parks: C.A.S.E. Project for L’Aquilaeng. Giuseppe Cefarelli, [email protected]
Fire design load combinationModify of the
Active and Passive Fire Protection
Design and Structural Model
Building description: Analysis of the structural characteristics
Choose of the Safety Performance Levels
Choose of the Active and Passive Fire Protection
Fire Model Fire Design Scenario
The model meets the safety levels choose?
Were tested all scenarios?
Static and fire design load calculation
Modify of the size or ty-pology of structural ele-
ments
Or
Thermal and structural analysis (for each fire design scenario)
YES
NO
END
YES
NO
Case Study: Car Parks of C.A.S.E. Project for L’Aquila
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1221
Combinations of actions for accidental design situations
Fire Safety Engineering for open and closed car parks: C.A.S.E. Project for L’Aquilaeng. Giuseppe Cefarelli, [email protected]
Modify of the Active and Passive Fire
Protection
Design and Structural Model
Building description: Analysis of the structural characteristics
Choose of the Safety Performance Levels
Choose of the Active and Passive Fire Protection
Fire Model Fire Design Scenario
The model meets the safety levels choose?
Were tested all scenarios?
Static and fire design load calculation
Modify of the size or ty-pology of structural ele-
ments
Or
Thermal and structural analysis (for each fire design scenario)
YES
NO
END
YES
NO
Case Study: Car Parks of C.A.S.E. Project for L’Aquila
Fire Scenarioqualitative description of the course of a firewith time identifying key events that characterise the fire and differentiate it from other possible fires. It typically defines the ignition and fire growth process, the fully developed stage, decay stage together with the building environment and systems that will impact on the course of the fire (EN1991-1-2)
Fire Safety Engineering for open and closed car parks: C.A.S.E. Project for L’Aquilaeng. Giuseppe Cefarelli, [email protected]
Technical References and GuidelineCEC Agreement 7215 - PP/025: “Demonstration of Real Fire Tests in Car Parks and HighBuildings”, by CITCM (France), PROFIL-ARBED Recherches (Luxembourg) e TNO (Netherlands),closed 2001INERIS Guideline: “Parcs de stationnement en superstructure largement ventiles. Avis d’expert sur les scénarios d’incendie”, Final Report 2001 by INERIS (Institut National de l’Environnement Industriel et des Risques) and by CTICM (Centre Technique Industriel de la Construction Metallique).REPORT PARCHEGGI (REPORT ON ITALIAN CAR PARKS): “Approccio ingegneristico per la sicurezza strutturale in caso di incendio di parcheggi aerati realizzati con struttura di acciaio”, Rapporto Interno Finale del 2010. Commissione per la Sicurezza delle Costruzioni di Acciaio in caso di Incendio.
Case Study: Car Parks of C.A.S.E. Project for L’AquilaThe fire scenario is significantly affected, among other things, by:- the geometry and- ventilation conditions of the compartment. As regards the evaluation of number of vehicles involved in the fire and the timing of fire initiation by a car to adjacent one, reference is made to the information provided by following Technical References and Guideline.
Fire Safety Engineering for open and closed car parks: C.A.S.E. Project for L’Aquilaeng. Giuseppe Cefarelli, [email protected]
Open Car ParksCEC Agreement 7215 - PP/025:
Resultslocalised fire, that is “pre-flashover” fire;
limited number of vehicles burn;fire propagation times by a car to adjacent
one is about 12 min
Calorimetric Hood tests.
The research consisted in:
Full-scale tests
INERIS Guideline
Car (category 3)
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Tempo [min]
RHR [kW]
Time (min)
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VAN
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Tempo [min]
RHR [kW]
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Location and number of cars involved in fire
Case Study: Fire Scenarios - Open Car Parks
Fire Safety Engineering for open and closed car parks: C.A.S.E. Project for L’Aquilaeng. Giuseppe Cefarelli, [email protected]
Closed Car ParksCEC Agreement 7215 - PP/025:
Results“pre-flashover” fire and post-flashover“ fire;
fire propagation times by a car to adjacent oneis about 6 min
Full-scale tests
Case Study: Fire Scenarios - Closed Car Parks
Fire Safety Engineering for open and closed car parks: C.A.S.E. Project for L’Aquilaeng. Giuseppe Cefarelli, [email protected]
Localised Fire Scenarios - Pre-flashover according to INERIS Guideline.
Propagation time 12min.
SCENARIO L1: 7 vehicles, of which 1 central VAN and 6 cars, that burn with a fire propagation time from car to adjacent one equals to 12 min from the VAN.SCENARIO L2: 4 vehicles, of which 1 central VAN and 3 cars surrounding a column, that burn with a fire propagation time from car to adjacent one equals to 12 min from the VAN.
0 m
in
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Generalized Fire Scenario- Post-flashover
SCENARIO D1: 34 vehicles, of which 2 central VAN and 32 cars, that burn with a fire propagation time from car to adjacent one equals to 6 min from the VAN
Propagation time 6 min.
Case Study: Design Fire Scenarios
Fire Safety Engineering for open and closed car parks: C.A.S.E. Project for L’Aquilaeng. Giuseppe Cefarelli, [email protected]
Hasemi’s Method[Annex C, EN1991-1-2]]
Qmp
H
ZS
ZP
0
Strato inf.
Strato sup.
mOUT,U
mOUT,LmOUT,L
mIN,L
QC
QR
mU , TU, VU, EU, U
mL , TL, VL, EL, L
p
Z
RHR curves Heat Fluxes on structural members
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One-Zone Model[Annex D, EN1991-1-2]
Case Study: Fire models
Generalized Fire Scenario
Localised Fire Scenarios 0
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Tempo [min]Time (min)
Temperature (°C)
Fire Safety Engineering for open and closed car parks: C.A.S.E. Project for L’Aquilaeng. Giuseppe Cefarelli, [email protected]
Modify of the Active and Passive Fire
Protection
Design and Structural Model
Building description: Analysis of the structural characteristics
Choose of the Safety Performance Levels
Choose of the Active and Passive Fire Protection
Fire Model Fire Design Scenario
The model meets the safety levels choose?
Were tested all scenarios?
Static and fire design load calculation
Modify of the size or ty-pology of structural ele-
ments
Or
Thermal and structural analysis (for each fire design scenario)
YES
NO
END
YES
NO
Case Study: Car Parks of C.A.S.E. Project for L’Aquila
Global Structural Analyses
Detailed 3D Structural Analyses
Fire Safety Engineering for open and closed car parks: C.A.S.E. Project for L’Aquilaeng. Giuseppe Cefarelli, [email protected]
Global Analyses
In order to limit the analysis time without compromising the accuracy of the results, thethermo-mechanical analyses, for each fire scenario, have been conducted with thereference to a significant substructure.
SAFIR 2007(University of Liege, Belgium)
Material Finite Element Section Thickness (mm)
Columns Steel S355 BEAM Circular Hollow
Dext = 800mm 15
Slab Concrete C30/37 SHELL Solid 500
Case Study: Thermo-Mechanical Structural Analyses
Fire Safety Engineering for open and closed car parks: C.A.S.E. Project for L’Aquilaeng. Giuseppe Cefarelli, [email protected]
Detailed 3D Analysesin order to calculate more accurately thethermal field and stresses distribution in thecapitals above the columns and to assessthe possible local buckling.
ABAQUS
Finite Element Properties of finite element
Thermal Analyses ABAQUS element DC3D4 4-node linear heat transfer tetrahedron
Mechanical Analyses ABAQUS element C3D10 10-node quadratic tetrahedron
For each fire scenario, the axial load at the top of column, corresponds to the axial load obtained by the global structural analyses.
Analyses have been conducted with reference to the more stressed and heated column
Case Study: Thermo-Mechanical Structural Analyses
Fire Safety Engineering for open and closed car parks: C.A.S.E. Project for L’Aquilaeng. Giuseppe Cefarelli, [email protected]
Thermal Analysis
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c a[J
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Specific heat Thermal conductivity
Localized fire Boundary conditons: Heat flux
Generalized fire Boundary conditons: Temperature vs time curve
Thermal properties of Steel (EN1993-1-2)
Case Study: Thermo-Mechanical Structural Analyses
Steel temperature Steel temperature
Fire Safety Engineering for open and closed car parks: C.A.S.E. Project for L’Aquilaeng. Giuseppe Cefarelli, [email protected]
Thermal expansion Strain-Stess Relationship
Boundary conditions: Thermal field obtained from Thermal Analysis
Mechanical properties of Steel (EN1993-1-2)
02468
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( L/
L)×1
03Case Study: Thermo-Mechanical Structural Analyses
Mechanical AnalysisLocalized fire
Generalized fire
Steel temperature
Fire Safety Engineering for open and closed car parks: C.A.S.E. Project for L’Aquilaeng. Giuseppe Cefarelli, [email protected]
0.00
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Fatto
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i rid
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0 0.025 0.05 0.075 0.1 0.125 0.15 0.175 0.2 0.225
20 °C100 °C200 °C300 °C400 °C500 °C600 °C700 °C800 °C900 °C1000 °C1100 °C
nom-nom
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[N
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nom
Strain-Stess Relationship
Case Study: Thermo-Mechanical Structural Analyses
Fire Safety Engineering for open and closed car parks: C.A.S.E. Project for L’Aquilaeng. Giuseppe Cefarelli, [email protected]
Thermal expansion Strain-Stess Relationship
Boundary conditions: Thermal field obtained from Thermal Analysis
Mechanical properties of Steel (EN1993-1-2)
02468
101214161820
0 300 600 900 1200Temperatura acciaio [°C]
( L/
L)×1
03Case Study: Thermo-Mechanical Structural Analyses
Mechanical AnalysisLocalized fire
Generalized fire
Steel temperature
0255075
100125150175200225250275300325350375
0 0.025 0.05 0.075 0.1 0.125 0.15 0.175 0.2 0.225
20 °C100 °C200 °C300 °C400 °C500 °C600 °C700 °C800 °C900 °C1000 °C1100 °C
nom-nom
nom
[N
/mm
2 ]
nom
Fire Safety Engineering for open and closed car parks: C.A.S.E. Project for L’Aquilaeng. Giuseppe Cefarelli, [email protected]
Modify of the Active and Passive Fire
Protection
Design and Structural Model
Building description: Analysis of the structural characteristics
Choose of the Safety Performance Levels
Choose of the Active and Passive Fire Protection
Fire Model Fire Design Scenario
The model meets the safety levels choose?
Were tested all scenarios?
Static and fire design load calculation
Modify of the size or ty-pology of structural ele-
ments
Or
Thermal and structural analysis (for each fire design scenario)
YES
NO
END
YES
NO
Case Study: Car Parks of C.A.S.E. Project for L’Aquila
Fire Safety Engineering for open and closed car parks: C.A.S.E. Project for L’Aquilaeng. Giuseppe Cefarelli, [email protected]
Fire scenario L2 – Global AnalysisTemperatures vs time
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BEAM 10 BEAM 20 BEAM 30 BEAM 40 BEAM 50BEAM 60 BEAM 70 BEAM 80 BEAM 90 BEAM 100BEAM 110 BEAM 120 BEAM 130 BEAM 140 BEAM 150BEAM 160 BEAM 170 BEAM 180 BEAM 190 BEAM 200
Temperature [°C]
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Beam 10 Beam 20 Beam 30 Beam 40 Beam 50Beam 60 Beam 70 Beam 80 Beam 90 Beam 100Beam 110 Beam 120 Beam 130 Beam 140 Beam 150Beam 160 Beam 170 Beam 180 Beam 190 Beam 200
Sforzo Normale [kN]
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Sforzo Normale [kN]
Tempo [min]
Riserva di resistenza t = 20min
Tmax = 587°C
Resistenza
Sollecitazione
Axial load (kN)
Time (min)Axial load effect
Axial loadresistance
Displacements vs time
Axial loads vs time
Axial load resistance vs time
Case Study: Global Analyses Results
There is not structural collapse
Fire Safety Engineering for open and closed car parks: C.A.S.E. Project for L’Aquilaeng. Giuseppe Cefarelli, [email protected]
Fire scenario L2 – Global analysisTemperatures vs time
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BEAM 10 BEAM 20 BEAM 30 BEAM 40 BEAM 50BEAM 60 BEAM 70 BEAM 80 BEAM 90 BEAM 100BEAM 110 BEAM 120 BEAM 130 BEAM 140 BEAM 150BEAM 160 BEAM 170 BEAM 180 BEAM 190 BEAM 200
Temperature [°C]
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Beam 10 Beam 20 Beam 30 Beam 40 Beam 50Beam 60 Beam 70 Beam 80 Beam 90 Beam 100Beam 110 Beam 120 Beam 130 Beam 140 Beam 150Beam 160 Beam 170 Beam 180 Beam 190 Beam 200
Sforzo Normale [kN]
Tempo [min]Time (min)
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Axial loads vs time
Case Study: Global Analyses Results
The maximum temperatures reached in the columns do not exceed 600°C
Because of the thermal curvature of the slabthe axial load of these columns increase
The axial load is further amplified from the differential thermal elongation of columns, exposed to different thermal conditions, which is constrained from slab shear stiffness
The columns displacement reflects, in general, the temperatures trend.
Displacements vs time
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Spostamento verticale [mm]
Tempo [min]Time (min)
Vertical displacement (mm)
Fire Safety Engineering for open and closed car parks: C.A.S.E. Project for L’Aquilaeng. Giuseppe Cefarelli, [email protected]
-4
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Spostamento verticale [mm]
Tempo [min]Time (min)
Vertical displacement (mm)
Columns Displacements
The maximum differential displacement, during the fire exposure, is about 16mm (between the column 120 and column 130) and this value corresponds to 2.6 ‰ below the limit value of 5.0 ‰.
Case Study: Global Analyses Results
Fire Safety Engineering for open and closed car parks: C.A.S.E. Project for L’Aquilaeng. Giuseppe Cefarelli, [email protected]
Axial load resistance vs time
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Sforzo Normale [kN]
Tempo [min]
Riserva di resistenza t = 20min
Tmax = 587°C
Resistenza
Sollecitazione
Axial load (kN)
Time (min)Axial load effect
Axial loadresistance
The axial load resistance of the column, evaluated according to EN1993-1-2, was compared with the axial load during the fire exposure.
Reserves of resistance
Case Study: Global Analyses Results
The more loaded column, even when the maximum temperature is reached, still has a significant reserves of resistance.
Fire Safety Engineering for open and closed car parks: C.A.S.E. Project for L’Aquilaeng. Giuseppe Cefarelli, [email protected]
Fire scenario L2 – Detailed analysis
Residual Plastic strain
The displacement at the top of column is very similar to those obtained in the global structural analyses. The final displacement is about 5mm in the central area of capital and about 2mm in the tube head: this is due to the plastic strain.
The 3D Thermal Analyses allowed to calculate more accurately the thermal field and stresses distribution in the capitals above the columns.
Case Study: Detailed Analyses Results
Fire Safety Engineering for open and closed car parks: C.A.S.E. Project for L’Aquilaeng. Giuseppe Cefarelli, [email protected]
Conclusions
The FSE application to car parks is facilitated by the information about thepossible fire scenarios provided by the European Research Project CECagreement 7215-PP/025 (2001) and from INERIS (2001) guideline.
The substructure extension has allowed assessing in an appropriate way boththe thermal field and the hyperstatic effects induced by different thermalexpansions of steel columns and bending of the concrete reinforced slab.
In addition to the global analysis, for each fire scenario, in order to calculatemore accurately the thermal field and stresses distribution in the capitalsabove the columns and to assess the possible local buckling, detailed 3Dthermo-mechanical analyses have been conducted with reference to themore stressed and heated column.
The thermo-mechanical analyses in fire situations for the described case studyshowed that the structures, and in particular the steel columns, consideredunprotected, satisfy the performance level set to the design fire scenarios, alsothanks to an overstrength in normal condition design.
Fire Safety Engineering for open and closed car parks: C.A.S.E. Project for L’Aquilaeng. Giuseppe Cefarelli, [email protected]
Future developments
The fire development and its effects on the structure will be evaluated bysoftware FDS in order to take into account the distribution of heat flux bothalong and around the columns.
How to link CFD fire model and structural model?
Through Adiabatic Surface Temperature?
Which value of coefficient of heat transfer byconvection should be assumed?
Which value of emissivity should be assumed?
Questions