Ali Nadjai MM Rafi, A Nadjai: Paper 783-788 INTRODUCTION Fire - PowerPoint PPT Presentation

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

INTRODUCTION  Fire performance of FRP RC structures unknown  Improved understanding in fire needed to:  ensure adequate levels of safety  provide clear design guidance  produce cost-effective design solutions  Research focussed on GFRP bars  Tests on CFRP bars reinforced beams at elevated temperatures described

TOPICS COVERED  Introduction  Experimental Programme  Instrumentation  Test Procedure  Test Results  Conclusions

INTRODUCTION  Reinforcing Steel Advantages Disadvantages Strength Oxidation Insufficient Cover Compatibility Poor Design Poor Workmanship Marine Environment Poor Mix Deicing Salts Aggressive Environment Contaminated aggregates Cont.

INTRODUCTION  FRP bars an alternate material  Fibres may compose of  Aramid AFRP  Carbon CFRP  Glass GFRP  Satisfactory performance at ambient temperature  Application limited to bridges Cont.

Impact of fire damage on the Economy of the Country WINDSOR TOWER THE DURATION OF FIRE WAS: 26 HOURS Madrid, the 14th of February of 2005

Fire of Disaster 200 200 150 150 100 100 50 50 WOUNDED WOUNDED DEAD DEAD 7

Fire and Natural Disasters Annual Costs

Minimum Fire Resistance for Members (Deemed to Satisfy rules

EXPERIMENTAL PROGRAMME  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  Beam’s notation  B = Beam  E = Elevated temperature  S = Steel, C = CFRP Cont.  For example BEC1

EXPERIMENTAL PROGRAMME  Simply supported beams  4 point load 400 mm 675 mm 675 mm  Total span = 2000 mm 1750 mm  Effective span = 1750 mm  Shear span = 675 mm  Heated length = 1550 mm  X-section = 120 x 200 mm

FireSERT - Europe’s most up to date Fire Research Facility Furnace for Single Sub-assembling Burning structures Item (SBI) 20 Mw Calorimeter 26/10/2010 - Presentation Title

Fire Test Facilities TGA/DTA/DSC TGA FTIR: Infra red Analysis for Gases Micro balance for Quantification of toxic gases

Fire Test Facilities UFA: Universal Flammability Apparatus Standard Cone

INSTRUMENTATION  LVDTs used to measure deflection and end slip  Thermocouples used to record temperature  Testing in floor furnace

TEST PROCEDURE  Load of 40% P u  Application 30 min prior to heating 20 15 Load (kN) 10 5 0 0 20 40 60 80 100 120 Cont. Time (min)

TEST PROCEDURE  Beam protected on top by adjacent slabs during fire  Concrete in compression unaffected Cont.

TEST PROCEDURE  Heating on three sides  Unheated length of 225 mm 1550 mm 225 mm 225 mm  Identification and marking of cracks Cont.

TEST PROCEDURE  Furnace as per ISO 834 heating curve  Standard and furnace temperatures compared 1400 1400 1200 1200 Temperature ( o C) Temperature ( o C) 1000 1000 ISO-834 ISO-834 800 800 Furnace- Furnace- - BESS20-1 600 600 400 400 200 200 0 0 0 0 50 50 100 100 150 150 200 200 250 250 Time (min) Time (min)

TEST RESULTS  Thermocouples fixed at several locations A TC5 A TC8 TC6 TC7 100 TC4 TC5 10 31 TC2 TC3 TC1 31 60 120 120 120 120 Cont. BESS20-1 BEHD20-2 BECS20-1 BEHD20-1

TEST RESULTS  Temperature distribution at a pair TC9 TC4 500 500 Temperature ( o C) Temperature ( o C) 400 400 300 300 TC4 TC9 200 200 100 100 0 0 0 0 10 10 20 20 30 30 40 40 50 50 60 60 70 70 Time (min) Time (min) Cont.

TEST RESULTS  Temperature distribution at another pair TC6 TC6 TC10 180 180 Temperature ( o C) Temperature ( o C) 150 150 120 120 TC10 TC6 90 90 60 60 30 30 0 0 0 0 10 10 20 20 30 30 40 40 50 50 60 60 70 70 Time (min) Time (min) Cont.

TEST RESULTS  Temperature distribution on rebar BESS20-1 B BESS20-1 B 500 500 Temperature ( o C) Temperature ( o C) 400 400 300 300 200 200 TC5 100 100 0 0 0 0 10 10 20 20 30 30 40 40 50 50 60 60 Cont. Time (min) Time (min)

TEST RESULTS  Temperature distribution at mid-span section 1000 1000 TC1 TC8 Temperature ( o C) 800 TC2 TC3 TC6 TC7 600 TC4 TC4 400 TC5 TC5 TC2 TC3 TC6 TC1 200 TC7 0 TC8 0 15 30 45 60 75 90 Time (min) Cont.

TEST RESULTS  Beam BECS20-1 before and after the test Before Heating After Heating Cont.

TEST RESULTS  Comparison of BECS20-1 and BESS20-1 after failure BECS20-1 BESS20-1 Cont. CFRP bar after fire

TEST RESULTS  Time-deflection history BESS20-1 Beam B Beam B BECS20-1 100 100 Deflection (mm) Deflection (mm) 80 80 60 60 40 40 20 20 0 0 0 0 20 20 40 40 60 60 80 80 100 100 Cont. Time (min) Time (min)

TEST RESULTS  Time-deflection history Beam B Beam B BESS20-1 BEHD20-1 BECS20-1 100 80 Deflection (mm) 60 40 20 0 0 20 40 60 80 100 120 Cont. Time (min)

TEST RESULTS  Time-deflection history Beam B Beam B BESS20-1 BEHD20-1 BECS20-1 BEHD20-2 100 80 Deflection (mm) 60 40 20 0 0 20 40 60 80 100 120 Cont. Time (min)

TEST RESULTS  Fire Rating  BESS20-1 – 80 min  BECS20-1 – 63 min  BEHD20-1 – 108 min  BEHD20-2 – 87 min Cont.

TEST RESULTS  Polymer softens at glass transition temperature T g 100 Deflection (mm) 80  T g of the resin as 96 o C 60 40  Heat distortion temperature 104 o C 20 0  Loss of bond strength at around 200 o C 0 20 40 60 80 100 Time (min)

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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