The increasing use of Fiber-Reinforced Polymer (FRP) composites in bridge infrastructure presents both opportunities and challenges for structural inspection and asset management. Although FRP systems offer superior corrosion resistance and high strength-to-weight ratios, their distinct material behavior and deterioration mechanisms are not adequately addressed in existing bridge inspection standards. This study presents a comprehensive framework for the field inspection and condition assessment of in-service FRP-reinforced and FRP-strengthened concrete bridge elements, developed in a research project funded by the Federal Highway Administration (FHWA). The framework integrates findings from experimental evaluation, nondestructive testing (NDT), and literature synthesis to produce a standardized methodology compatible with the Specifications for the National Bridge Inventory (SNBI) and the AASHTO Manual for Bridge Element Inspection (MBEI). It introduces FRP-specific element identifiers, defect typologies, and condition-rating scales consistent with national bridge data structures, enabling quantitative evaluation and uniform reporting across transportation agencies. The framework represents a foundational step toward incorporating composite materials into the federally mandated bridge management systems established under 23 CFR 650.317, facilitating data-driven maintenance, lifecycle analysis, and policy development.
ACI 440.1R-15. Guide for the design and construction of structural concrete reinforced with Fiber-reinforced Polymer (FRP) bars (ACI 440.1R-15). American Concrete Institute, 2015.
4.
ACI 440.2R-17. Guide for the design and construction of externally bonded FRP systems for strengthening concrete structures, 2017.
5.
KossakowskiPGWciślikW. Fiber-reinforced polymer composites in the construction of bridges: opportunities, problems and challenges. Fibers2022; 10(4): 37.
6.
TripathiSBoharaRPMallaP, et al.Seismic retrofitting of non-ductile RC beam-column joint with externally bonded CFRP sheets. Int J Adv Eng Manag2019; 4(2): 1–7.
7.
TangL. Maintenance and inspection of fiber-reinforced polymer (FRP) bridges: a review of methods. Mater (Basel, Switzerland)2021; 14(24): 7826.
8.
NBIS. National bridge Inspection Standards [NBIS], 2022, pp. 1–20.
9.
FHWA, Specifications for the national bridge inventory, 2022.
10.
AASHTO. Manual for bridge element inspection. American Association of State Highway and Transportation Officials, 2019.
11.
FowlerTKinraVKMaslovK, et al.Research report: inspecting frp composite structures with nondestructive testing. Report2001; 7(19): 148.
12.
MehrabiAKhedmatgozar DolatiSSMallaP, et al.A framework for field inspection of In-Service FRP reinforced/strengthened concrete bridge elements. 2024. [Online]. Available: https://rosap.ntl.bts.gov/view/dot/73333
13.
MehrabiAKhedmatgozar DolatiSSMallaP, et al.A framework for field inspection of In-service FRP reinforced/strengthened concrete bridge elements. Technical Summary, 2025. [Online]. Available: https://rosap.ntl.bts.gov/view/dot/85145
14.
QureshiJ. A review of fibre reinforced polymer bridges. Fibers2023; 11(5): 40.
15.
AliHTAkramiRFotouhiS, et al.Fiber reinforced polymer composites in bridge industry. Structures2020; 30: 774–785.
16.
AASHTO. Guide specifications for design of bonded FRP systems for repair and strengthening of concrete bridge elements. American Association of State Highway and Transportation Officials, 2023.
17.
AzadMMJungJElahiMU, et al.Failure modes and non-destructive testing techniques for fiber-reinforced polymer composites. J Mater Res Technol2024; 33: 9519–9537.
18.
KangTHKHowellJKimS, et al.A state-of-the-art review on debonding failures of FRP laminates externally adhered to concrete. Int J Concr Struct Mater2012; 6(2): 123–134.
19.
WangBZhongSLeeT-L, et al.Non-destructive testing and evaluation of composite materials/structures: a state-of-the-art review. Adv Mech Eng2020; 12(4): 1687814020913761.
20.
DuttaSS. Nondestructive evaluation of FRP wrapped concrete cylinders using infrared thermography and groud penetrating radar. West Virginia University, 2006.
21.
HingCLCHalabeUB. Nondestructive testing of GFRP bridge decks using ground penetrating radar and infrared thermography. J Bridge Eng2010; 15(4): 391–398.
22.
MallaPDolatiSSKOrtizJD, et al.Damage detection in FRP reinforced concrete elements. Materials2024; 17(5): 1171.
23.
OrtizJDDolatiSSKMallaP, et al.Nondestructive testing (NDT) for damage detection in concrete elements with externally bonded fiber-reinforced polymer. Buildings2024; 14(1): 246.
24.
MallaPKhedmatgozar DolatiSSOrtizJD, et al.Feasibility of conventional non-destructive testing methods in detecting embedded FRP reinforcements. Appl Sci2023; 13(7): 4399.
25.
TashanJAl-MahaidiR. Bond defect detection using PTT IRT in concrete structures strengthened with different CFRP systems. Compos Struct2014; 111(1): 13–19.
26.
WenBZhouZZengB, et al.Pulse-heating infrared thermography inspection of bonding defects on carbon fiber reinforced polymer composites. Sci Prog2020; 103(3): 36850420950131.
27.
CantiniLCucchiMFavaG, et al.Damage and defect detection through infrared thermography of fiber composites applications for strengthening of structural elements. In: RILEM Bookseries, 2012, vol 6, pp. 779–784.
28.
CaldeiraMMPadaratzIJ. Potentialities of infrared thermography to assess damage in bonding between concrete and GFRP. Rev IBRACON Estrut Mater2015; 8(3): 296–322.
29.
CorvagliaPLargoA. IRT survey for the quality control of FRP reinforced r.c. Structures 2008. Proceedings of the QIRT.
30.
BanthiaNAidinADemersM, et al.Durability of FRP-concrete bond in FRP-strengthened bridges. Concr Int2010; 32(8): 45–51.
31.
KyliliAFokaidesPAChristouP, et al.Infrared thermography (IRT) applications for building diagnostics: a review. Appl Energy2014; 134: 531–549.
32.
BrownJRChittineniSH. Comparison of lock-in and pulse-phase thermography for defect characterization in FRP composites applied to concrete. Thermosense Therm. Infrared Appl. XXXVII2015; 9485: 94850B.
33.
ZiGSimJGOhH, et al.Optimum NDT using infrared thermography for defected concrete. In: Bridge Maintenance, Safety, Management, Health Monitoring and Informatics—IABMAS ’08: Fourth International IABMAS Conference, 2008, pp. 1223–1230.
34.
DumoulinJIbarra-CastanedoCQuiertantM, et al.Evaluation of FRP gluing on concrete structures by active infrared thermography, 2010. Proceedings of the QIRT; 155–163.
35.
MilovanovićBBanjad PečurI. Review of active IR thermography for detection and characterization of defects in reinforced concrete. J Imaging2016; 2(2): 11.
36.
FoudaziADonnellKMGhasrMT. Application of active microwave thermography to delamination detection. In: 2014 IEEE International Instrumentation and Measurement Technology Conference (I2MTC) Proceedings, 2014, IEEE, pp. 1567–1571.
37.
MtengaPVParzychJGLimerickR. Quality assurance of FRP retrofit using infrared thermography. Struct - A Struct Eng Odyssey, Struct 2001 - Proc 2001 Struct Congr Expo2004; 109: 1–8.
38.
NokesJPHawkinsGF, Infrared inspection of composite-reinforced concrete structures, 2001.
39.
GaliettiULupranoVNennaS, et al.Non-destructive defect characterization of concrete structures reinforced by means of FRP. Infrared Phys Technol2007; 49(3): 218–223.
40.
JacksonDIslamMAlampalliS. Feasibility of evaluating the performance of fiber reinforced plastic (FRP) wrapped reinforced concrete columns using ground penetrating RADAR (GPR) and infrared (IR) thermography techniques. In: Structural Materials Technology IV-An NDT Conference, 2000, pp. 390–395.
41.
YazdaniNBeneberuERiadM. Nondestructive evaluation of FRP-concrete interface bond due to surface defects. Adv Civ Eng2019; 2019: 2563079.
42.
LupranoVATundoAAngelo TatìI, et al.Non destructive defect characterization in civil structures reinforced by means of FRP. Proceedings of ECNDT 2006. 2006.
43.
KaiserHKarbhariVMSikorskyC. Non-destructive testing techniques for FRP rehabilitated concrete ± II: an assessment. International Journal of Materials and Product Technology. 2004; 21(5): 385–401.
44.
SenR, Developments in the durability of FRP-concrete bond. Constr Build Mater2015; 78: 112–125.
45.
HaqueARajuPK. Sensitivity of the Acoustic impact technique in characterizing defects/damage in laminated composites. J Reinf Plast Compos1995; 14(3): 280–296.
46.
DolatiSSKMallaPOrtizJD, et al.Identifying NDT methods for damage detection in concrete elements reinforced or strengthened with FRP. Eng Struct2023; 287: 116155.
47.
Khedmatgozar DolatiSSMallaPOrtizJD, et al.Non-destructive testing applications for in-service FRP reinforced/strengthened concrete bridge elements. In: Nondestructive characterization and monitoring of advanced materials, aerospace, civil infrastructure, and transportation XVI2022; 12047: 59–74.
48.
DolatiSSKMallaPPolancoJO, et al.Nondestructive testing applications for FRP reinforced or strengthened concrete elements. Structures Congress2023; 12047: 217–229.
49.
OrtizJDKhedmatgozar DolatiSSMallaP, et al.FRP-Reinforced/Strengthened concrete: state-of-the-art review on durability and mechanical effects. Materials2023; 16(5): 1–30.
50.
MallaPKhedmatgozar DolatiSSOrtizJD, et al.Damage and defects in fiber-reinforced polymer reinforced and strengthened concrete elements. J Compos Constr2023; 27(4): 04023035.
51.
MallaPDolatiSSKOrtizJD, et al.Applicability of available NDT methods for damage detection in concrete elements reinforced or strengthened with FRP. Bridge Struct2023; 19(4): 149–164.
52.
TelangNMDumlaoCMehrabiAB, et al.NCHRP report 564: field inspection of In-Service FRP bridge decks. Transp Res Board2006.
53.
PeveyJMRichWBWilliamsCS, et al.Repair and strengthening of bridges in Indiana using fiber reinforced polymer systems: volume 1—Review of current FRP repair systems and application methodologies2021.
54.
KarbhariVMKaiserHNavadaR, et al.Methods for detecting defects in composite rehabilitated concrete structures, 2005.
55.
BaniyaAMilevSHenryR, et al.Durability sssessment of externally bonded Fiber-Reinforced Polymer (FRP) composite repairs in bridges. 2022; (Center for Integrated Asset Management for Multimodal Transportation Systems (CIAMTIS) (UTC)).
56.
KianiNAbedinMSteputatCC, et al.Structural health monitoring of FRP-reinforced concrete bridges using vibration responses. Springer International Publishing, 2022.
