SLIDE 1
Experimental Evaluation of Fire Resistance of FRP and Hybrid RC Beams – Part 1
Fire Safety Engineering Research and Technology Centre (FireSERT)
Ali Nadjai
MM Rafi, A Nadjai: Paper 783-788
SLIDE 2 Research focussed on GFRP bars INTRODUCTION Fire performance of FRP RC structures unknown Tests on CFRP bars reinforced beams at elevated temperatures described Improved understanding in fire needed to:
- ensure adequate levels of safety
- provide clear design guidance
- produce cost-effective design solutions
SLIDE 3
TOPICS COVERED Introduction Experimental Programme Instrumentation Test Procedure Test Results Conclusions
SLIDE 4
INTRODUCTION Reinforcing Steel Advantages Strength Oxidation Disadvantages Compatibility Insufficient Cover Poor Design Poor Workmanship Poor Mix Aggressive Environment Marine Environment Contaminated aggregates Deicing Salts
Cont.
SLIDE 5 Fibres may compose of
INTRODUCTION FRP bars an alternate material
AFRP CFRP GFRP
Satisfactory performance at ambient temperature Application limited to bridges
Cont.
SLIDE 6 WINDSOR TOWER Madrid, the 14th of February of 2005
THE DURATION OF FIRE WAS: 26 HOURS
Impact of fire damage on the Economy of the Country
SLIDE 7 100 200 150 50
WOUNDED DEAD 7
Fire of Disaster
100 200 150 50
WOUNDED DEAD
SLIDE 8
Fire and Natural Disasters Annual Costs
SLIDE 9
Minimum Fire Resistance for Members (Deemed to Satisfy rules
SLIDE 10 One steel and two CFRP reinforced beams Tension Reinforcement
- Two 10mm steel bars OR
- Two 9.5mm CFRP bars
Two 8mm steel bars on top 6mm rings at 100mm spacing EXPERIMENTAL PROGRAMME
Cont.
Beam’s notation
- B = Beam
- E = Elevated temperature
- S = Steel, C = CFRP
For example BEC1
SLIDE 11 EXPERIMENTAL PROGRAMME Simply supported beams
- 4 point load
- Total span = 2000 mm
- Effective span = 1750 mm
- Shear span = 675 mm
- Heated length = 1550 mm
- X-section = 120 x 200 mm
675 mm 675 mm 400 mm 1750 mm
SLIDE 12 FireSERT - Europe’s most up to date Fire Research Facility
26/10/2010 - Presentation Title
Single Burning Item (SBI) 20 Mw Calorimeter Furnace for Sub-assembling structures
SLIDE 13 TGA
FTIR: Infra red Analysis for Gases
TGA/DTA/DSC Micro balance for Quantification
Fire Test Facilities
SLIDE 14 Standard Cone
UFA: Universal Flammability Apparatus
Fire Test Facilities
SLIDE 15
INSTRUMENTATION
LVDTs used to measure deflection and end slip Thermocouples used to record temperature Testing in floor furnace
SLIDE 16 TEST PROCEDURE Load of 40% Pu Application 30 min prior to heating
5 10 15 20 20 40 60 80 100 120
Time (min) Load (kN)
Cont.
SLIDE 17
TEST PROCEDURE Concrete in compression unaffected Beam protected on top by adjacent slabs during fire
Cont.
SLIDE 18 TEST PROCEDURE Heating on three sides
225 mm 225 mm 1550 mm
Identification and marking of cracks Unheated length of 225 mm
Cont.
SLIDE 19 200 400 600 800 1000 1200 1400 50 100 150 200 250
Time (min) Temperature (oC)
200 400 600 800 1000 1200 1400 50 100 150 200 250
Time (min) Temperature (oC)
TEST PROCEDURE Furnace as per ISO 834 heating curve Standard and furnace temperatures compared
Furnace- ISO-834
Furnace- ISO-834
SLIDE 20 TEST RESULTS Thermocouples fixed at several locations
Cont.
A A
TC5
TC1 TC2 TC3 TC4 TC5 TC6 TC7 TC8 100 120 60 31 10 31 120 120 120
BECS20-1 BESS20-1 BEHD20-1 BEHD20-2
SLIDE 21 100 200 300 400 500 10 20 30 40 50 60 70
Time (min) Temperature (oC)
TEST RESULTS Temperature distribution at a pair
TC4
TC4 TC9
Cont.
100 200 300 400 500 10 20 30 40 50 60 70
Time (min) Temperature (oC)
TC9
SLIDE 22 30 60 90 120 150 180 10 20 30 40 50 60 70
Time (min) Temperature (oC)
30 60 90 120 150 180 10 20 30 40 50 60 70
Time (min) Temperature (oC)
TEST RESULTS Temperature distribution at another pair
Cont.
TC10
TC6 TC10
TC6
TC6
SLIDE 23 100 200 300 400 500 10 20 30 40 50 60
Time (min) Temperature (oC)
100 200 300 400 500 10 20 30 40 50 60
Time (min) Temperature (oC)
TEST RESULTS Temperature distribution on rebar
Cont.
TC5
B B
BESS20-1 BESS20-1
SLIDE 24 TEST RESULTS
Cont.
Temperature distribution at mid-span section
TC1 TC2 TC3 TC4 TC5 TC6 TC7 TC8
200 400 600 800 1000 15 30 45 60 75 90
Time (min)
TC1 TC2 TC3 TC4 TC5 TC6 TC7 TC8
1000 Temperature (oC)
SLIDE 25
TEST RESULTS Beam BECS20-1 before and after the test
Cont. Before Heating After Heating
SLIDE 26 TEST RESULTS
Comparison of BECS20-1 and BESS20-1 after failure
Cont.
BECS20-1 BESS20-1 CFRP bar after fire
SLIDE 27 20 40 60 80 100 20 40 60 80 100
Time (min) Deflection (mm)
20 40 60 80 100 20 40 60 80 100
Time (min) Deflection (mm)
TEST RESULTS Time-deflection history
Cont. Beam B Beam B
BESS20-1 BECS20-1
SLIDE 28 TEST RESULTS Time-deflection history
Cont. Beam B Beam B
BESS20-1 BECS20-1
20 40 60 80 100 20 40 60 80 100 120 Time (min) Deflection (mm)
BEHD20-1
SLIDE 29 TEST RESULTS Time-deflection history
Cont. Beam B Beam B
BESS20-1 BECS20-1 BEHD20-1 BEHD20-2
20 40 60 80 100 20 40 60 80 100 120 Time (min) Deflection (mm)
SLIDE 30 TEST RESULTS
Fire Rating
- BESS20-1 – 80 min
- BECS20-1 – 63 min
- BEHD20-1 – 108 min
- BEHD20-2 – 87 min
Cont.
SLIDE 31 Polymer softens at glass transition temperature Tg Tg of the resin as 96oC Heat distortion temperature 104oC Loss of bond strength at around 200oC
20 40 60 80 100 20 40 60 80 100
Time (min) Deflection (mm)
TEST RESULTS
SLIDE 32
CONCLUSIONS No change in temperature along the length Similar temperature for steel and CFRP bars More stiff FRP RC beam than steel RC beam Similar fire resistance of BEC and BES1 beams Hybrid beams more strong and ductile compared to FRP RC beam
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SLIDE 34
THANK YOU FOR YOUR ATTENTION !
