new experimental evidences
TRANSCRIPT
Fire Behaviour of Steel and Composite Floor SystemsNew Experimental Evidences
2New Experimental Evidences
• Objectives of new fire tests• Full scale fire tests within the projects of
– FRACOF (Test 1 ISO Fire)– COSSFIRE (Test 2 ISO Fire)– FICEB (Test 3 Natural fire & Cellular Beams)
• Test set-up• Experimental results
– Temperature– Displacement
• Observation and analysis• Comparison with simple design methods• Conclusion
Content of presentation
3New Experimental Evidences
• Background– Cardington fire tests
• Excellent fire performance under natural fire condition• Max of steel 1150 °C, fire duration 60 min
(> 800°C)• UK construction details
• Objectives– To confirm same good performance under long fire
duration (at least 90 minutes of ISO fire)– To investigate the impact of different construction details,
such as reinforcing steel mesh and fire protection of edgebeams
– To validate different fire safety engineering tools
Why more fire tests?
Objectives
Test set-up
Experimental
results &
Observation
Comparison with
simple design
methods
Conclusion
4New Experimental Evidences
Structure grid of a real building
Adopted steel frames for fire Test 1
CORNER
• Test 1 (FRACOF)
Design of test specimens
Objectives
Test set-up
Experimental
results &
Observation
Comparison with
simple design
methods
Conclusion
5New Experimental Evidences
Adopted steel frames for fire Test 2
EDGE
PART
• Test 2 (COSSFIRE)
Structure grid of a real building
Design of test specimens
Objectives
Test set-up
Experimental
results &
Observation
Comparison with
simple design
methods
Conclusion
6New Experimental Evidences
Test 1
• Final composite floor systems
Design of test specimens
Test 2
Objectives
Test set-up
Experimental
results &
Observation
Comparison with
simple design
methods
Conclusion
7New Experimental Evidences
• Steel frame– Steel and concrete composite beams
• According to Eurocode 4 part 1-1 (EN1994-1-1)– Short steel columns
• Composite slab– Total depth
• According to Eurocode 4 part 1-2 (EN1994-1-2)– Reinforcing steel mesh
• Based on simple design rules
• Steel joints– Commonly used joints: double angle and end plate
• According to Eurocode 3 part 1-8 (EN1993-1-8)
Design of structural members
Objectives
Test set-up
Experimental
results &
Observation
Comparison with
simple design
methods
Conclusion
8New Experimental Evidences
• Arrangement of headed studs over steel beams
Primary beamsSecondary beams
• Type of steel studs– TRW Nelson KB 3/4" – 125 (Φ = 19mm; h = 125 mm;
fy = 350 N/mm²; fu = 450 N/mm²)
109 207 m m 207 m m
125 m m
300 mm Test 2 100 mm Test 1
125 mm
Design of structural members
Objectives
Test set-up
Experimental
results &
Observation
Comparison with
simple design
methods
Conclusion
9New Experimental Evidences
Beam to columnBeam to beam
Secondary beam Primary beam
Double angle web cleats Flexible end plate Double angle web
cleats
Grade of steel bolts: 8.8Diameter of steel bolt: 20 mm
Steel joints
Objectives
Test set-up
Experimental
results &
Observation
Comparison with
simple design
methods
Conclusion
10New Experimental Evidences
Composite slab
Steel deck: COFRAPLUS60 – 0.75 mmConcrete quality: C30/37
155
mm
Tes
t 113
5 m
m T
est 2
58 m
m
Reinforcing steel mesh
Mesh size: 150x150Diameter: 7 mmSteel grade: S500Axis distance from top of the slab:• 50 mm Test 1• 35 mm Test 2
62 mm
101 mm 107 mm
Sizes of structural members
Objectives
Test set-up
Experimental
results &
Observation
Comparison with
simple design
methods
Conclusion
11New Experimental Evidences
15 sand bags of 1512 kgEquivalent
uniform load: 390 kg/m²
20 sand bags of 1098 kgEquivalent
uniform load: 393 kg/m²
T e s t 1
Test 2
Mechanical loading condition
Objectives
Test set-up
Experimental
results &
Observation
Comparison with
simple design
methods
Conclusion
12New Experimental Evidences
1 2
3 4
Preparation of fire test 2
Objectives
Test set-up
Experimental
results &
Observation
Comparison with
simple design
methods
Conclusion
13New Experimental Evidences
Before the test
Unprotected
secondary beams
Composite slab
After the test
Behaviour of the floor during fire
Objectives
Test set-up
Experimental
results &
Observation
Comparison with
simple design
methods
Conclusion
14New Experimental Evidences
Structure of the Test 3 (FICEB)
Objectives
Test set-up
Experimental
results &
Observation
Comparison with
simple design
methods
Conclusion
Beam-1
Beam-3Beam-4
Beam-5Beam-solid
Column GL-D Column
GL-A
15New Experimental Evidences
Structure of the Test 3
Objectives
Test set-up
Experimental
results &
Observation
Comparison with
simple design
methods
Conclusion
16New Experimental Evidences
Structure of the Test 3
Objectives
Test set-up
Experimental
results &
Observation
Comparison with
simple design
methods
Conclusion
Beam - Beam Connections
17New Experimental Evidences
Structure of the Test 3
Objectives
Test set-up
Experimental
results &
Observation
Comparison with
simple design
methods
Conclusion
Beam - Column Connections
18New Experimental Evidences
Structure of the Test 3
Objectives
Test set-up
Experimental
results &
Observation
Comparison with
simple design
methods
Conclusion
A393 Mesh Reinforcement, dia 10mm
Full Interaction: between slab & beams, achieved by Shear connectors, dia 19, h=95mm
U-bars reinf. around the slab was added to ensure correct reinfor. Detail requirement for Ambient Temp.
19New Experimental Evidences
Structure of the Test 3
Objectives
Test set-up
Experimental
results &
Observation
Comparison with
simple design
methods
Conclusion
20New Experimental Evidences
Structure of the Test 3
Objectives
Test set-up
Experimental
results &
Observation
Comparison with
simple design
methods
Conclusion
Fire load energy density was700MJ/m2
The fire load can be achieved using 45 standard wooden cribs(1m x 1m x 0.5 m high), positioned evenly around the compartment(9.0m x 15.0m).
WOODEN CRIBS LOCATION
21New Experimental Evidences
• Fire temperature
• Heating of unprotected steel beams
• Heating of protected steel members
• Heating of composite slab
• Deflection of the floor
• Observations over the behaviour of composite floor systems
– Concrete cracking and concrete crushing
– Failure of reinforcing steel mesh during the test
– Collapse of edge beams
Experimental results
Objectives
Test set-up
Experimental
results &
Observation
Comparison with
simple design
methods
Conclusion
22New Experimental Evidences
• Fire temperature
Experimental results
Objectives
Test set-up
Experimental
results &
Observation
Comparison with
simple design
methods
Conclusion
0
200
400
600
800
1000
1200
0 30 60 90 120 150 180 210 240
Tem
pera
ture
(°C
)
Time (min)
ISO834
FRACOF
COSSFIRE
Test 1
Test 2
23New Experimental Evidences
• Test 3 Fire temperature
Experimental results
Objectives
Test set-up
Experimental
results &
Observation
Comparison with
simple design
methods
Conclusion
24New Experimental Evidences
• Heating of unprotected steel beams
Experimental results
Objectives
Test set-up
Experimental
results &
Observation
Comparison with
simple design
methods
Conclusion
Test 1 Test 2
25New Experimental Evidences
• Test 3 Heating of unprotected steel beams
Experimental results
Objectives
Test set-up
Experimental
results &
Observation
Comparison with
simple design
methods
Conclusion
Beam 4 Zone 3 Centre
0
200
400
600
800
1000
1200
0 20 40 60 80 100 120 140 160
Time (min)
Tempe
rature (°C )
A B C D E F
26New Experimental Evidences
• Heating of protected steel beams
• Observation– Much hotter beams in Test 2 550 °C and one edge
secondary beam heated up to > 600 °C
Experimental results
Objectives
Test set-up
Experimental
results &
Observation
Comparison with
simple design
methods
Conclusion
Test 1
Test 2
27New Experimental Evidences
• Heating of composite slab
Test 1 Test 2
Experimental results
Objectives
Test set-up
Experimental
results &
Observation
Comparison with
simple design
methods
Conclusion
28New Experimental Evidences
• Test 3 Heating of composite slab
Experimental results
Objectives
Test set-up
Experimental
results &
Observation
Comparison with
simple design
methods
Conclusion
29New Experimental Evidences
• Displacement transducers for deflection
D1
D2
D3
D4
800 mm
D5 D2 D1
D3
D4
D7
D6
D8
1300mm
1300mm
1660 mm
1300mm
Experimental results
Test 1 Test 2
Objectives
Test set-up
Experimental
results &
Observation
Comparison with
simple design
methods
Conclusion
30New Experimental Evidences
• Deflection of the floors
050
100150200250300350400450500550600
0 30 60 90 120 150 180 210 240
Vert
ical
dis
plac
emen
t (m
m)
Time (min)
D1
D4D3
D2
050
100150200250300350400450500550600
0 30 60 90 120 150 180 210 240
Vert
ical
dis
plac
emen
t (m
m)
Time (min)
D1 D3
D2 D4
D5
D6D7 D8
Extrapolated results
Experimental results
Test 1 Test 2
Objectives
Test set-up
Experimental
results &
Observation
Comparison with
simple design
methods
Conclusion
31New Experimental Evidences
• Test 3 Displacement transducers for deflection
Experimental results
Objectives
Test set-up
Experimental
results &
Observation
Comparison with
simple design
methods
Conclusion
MEASURE DEVICE LOCATION (T/C & LVDT)
32New Experimental Evidences
• Test 3 Deflection of the floor
Experimental results
Objectives
Test set-up
Experimental
results &
Observation
Comparison with
simple design
methods
Conclusion
33New Experimental Evidences
• Cracking of concrete (Test 1)
• Observation– Excellent global stability of the floor despite the
failure of reinforcing steel mesh
Experimental results
Objectives
Test set-up
Experimental
results &
Observation
Comparison with
simple design
methods
Conclusion
34New Experimental Evidences
• Cracking of concrete (Test 3)
Concrete crack
• Observation– Excellent global stability of the floor despite
appearance of the crack
Experimental results
Objectives
Test set-up
Experimental
results &
Observation
Comparison with
simple design
methods
Conclusion
35New Experimental Evidences
• Web instability of the beam (Test 3)
Experimental results
Objectives
Test set-up
Experimental
results &
Observation
Comparison with
simple design
methods
Conclusion
36New Experimental Evidences
• Crushing of concrete (Test 2)
• Observation– Global stability of the floor maintained
appropriately despite the failure of one edge beam
Experimental results
Objectives
Test set-up
Experimental
results &
Observation
Comparison with
simple design
methods
Conclusion
37New Experimental Evidences
Test 1 Test 2
Test Simple design methods Test Simple design
methods
Fire rating (min) > 120 120 > 120 96
Deflection (mm) 450 366(*) 510 376(*)
• Observation– Experimental results:
Fire rating > 120 minutes
Comparison with simple design rules
Objectives
Test set-up
Experimental
results &
Observation
Comparison with
simple design
methods
Conclusion
38New Experimental Evidences
• General conclusions relative to new fire tests– Excellent performance of the composite floor systems
behaving under membrane action for long ISO fireexposure (>120 minutes)
– High level of robustness of the composite floor systemdespite certain local failures
– Specific attention to be paid to construction detailswith respect to reinforcing steel mesh in order toensure a good performance of integrity criteria
– Simple design method is on the safe side incomparison with test results
– No sign of failure during cooling phase of thecomposite floor systems
New experimental evidences
Objectives
Test set-up
Experimental
results &
Observation
Comparison with
simple design
methods
Conclusion