Description
In recent years, fiber-reinforced polymers (FRP) have emerged as an attractive alternative for internal (primary) reinforcement in new constructions and as external (secondary) reinforcement in retrofitting and strengthening concrete structures. This is mainly due to the numerous advantages FRP offers over traditional steel reinforcement. In spite of the numerous advantages of FRP, there is limited information on the fire resistance of FRP-incorporated concrete structures. This is due to a lack of reliable fire test data and specific testing protocols for undertaking fire resistance tests on FRP-incorporated concrete structural members. The lack of specific fire resistance provisions in codes and standards continues to restrict the use of FRP in structural applications, where fire safety is a critical design consideration.
To address the fire performance issues of FRP, a study was carried out to review the state-of-the art, identify knowledge gaps, and then develop a testing program, together with fire testing protocols, for undertaking needed fire resistance tests on FRP-incorporated structural concrete members. This report presents a summary of existing research on the performance of FRP-incorporated concrete structures in fire. The available information is critically analyzed to evaluate the effect of elevated temperatures on the properties of FRP composites and also on the fire resistance of FRP-incorporated concrete structures. The review and analysis cover all three FRP-incorporated constructions: internally reinforced (IR), externally bonded (EB), and near surface mounted (NSM) concrete structures – however, this report focuses on IR concrete structures. Based on the review, a number of knowledge gaps relating to fire resistance of FRP-incorporated concrete members are identified. To address the current shortcomings, a testing program and fire testing protocols are proposed to undertake fire resistance tests on -internally reinforced FRP concrete members. Finally, recommendations are laid out for developing effective fire resistance strategies and guidelines for deploying codes and standards.
Keywords:
NEx, fiber reinforced polymer composites, FRP, FRP reinforcement, fire, fire resistance, fire tests, fire performance, buildings, bridges
Table of Contents
EXECUTIVE SUMMARY ... 3
ACKNOWLEDGEMENTS ... 4
TABLE OF CONTENTS ... 5
1. INTRODUCTION ... 6
2. PROJECT OBJECTIVES ... 8
3. FIBER-REINFORCED POLYMER COMPOSITES ... 9
3.1 GENERAL ... 9
3.2 PROPERTIES OF FRP COMPOSITES AT ROOM TEMPERATURES AND KEY PERFORMANCE ISSUES ... 11
3.3 PROPERTIES OF FRP COMPOSITES AT ELEVATED TEMPERATURES AND KEY PERFORMANCE ISSUES ... 13
3.3.1 Combustibility Properties ... 13
3.3.2 Thermal Properties ... 14
3.3.3 Mechanical Properties ... 14
3.3.4 Bond Properties ... 15
3.3.5 Deformation Properties ... 16
3.4 APPLICATIONS OF FRP IN CONCRETE STRUCTURES ... 17
3.5 NEED FOR FIRE RESISTANCE IN FRP-INCORPORATED CONCRETE STRUCTURES ... 18
3.6 RESPONSE OF FRP-INCORPORATED RC STRUCTURES UNDER FIRE ... 19
4. PREVIOUS STUDIES ON EVALUATING FIRE RESISTANCE ... 20
4.1 METHODOLOGY ADOPTED FOR LITERATURE REVIEW ... 20
4.2 FIRE TESTS/EXPERIMENTS ... 21
4.3 NUMERICAL STUDIES ... 27
4.4 DESIGN PROVISIONS IN CODES AND STANDARDS ... 28
5. FIRE PERFORMANCE OF FRP-INCORPORATED CONCRETE STRUCTURES ... 33
5.1 BEHAVIOR OF FRP-INCORPORATED CONCRETE MEMBERS UNDER FIRE EXPOSURE ... 33
5.2 STRATEGIES FOR ACHIEVING REQUIRED FIRE RESISTANCE ... 37
5.3 METHODS FOR EVALUATING FIRE RESISTANCE ... 37
5.3.1 Standardized Test Methods ... 37
5.3.2 Rational Calculation Approaches for Evaluating Fire Resistance ... 38
6. CURRENT KNOWLEDGE GAPS ... 41
7. TEST MATRIX AND TESTING PROTOCOLS ... 43
7.1 TEST MATRIX FOR FIRE RESISTANCE TESTS ... 43
7.2 TESTING PROTOCOLS FOR UNDERTAKING FIRE RESISTANCE TESTS ... 47
8. KEY RECOMMENDATIONS FOR RESEARCH PRIORITIES/NEXT STEPS ... 50
LIST OF ACRONYMS ... 53
REFERENCES ... 54
APPENDIX ... 57