Effect of Spike Anchors in the Bond Behavior of FRCM Systems Applied onto Curved Masonry Substrates
Publication: Journal of Composites for Construction
Volume 27, Issue 6
Abstract
Externally bonded composite systems are commonly used for the structural strengthening of existing arched masonry structures. Textile-reinforced mortar systems applied to masonry arch intrados allow the load carrying capacity of the structure to be increased and the infrastructure to be kept in service during application of strengthening systems. The structural performance of mortar-based materials [i.e., fabric-reinforced cementitious matrix (FRCM), textile-reinforced mortar (TRM), and steel-reinforced grout (SRG)] depends on the bond properties between the matrix and the substrate and between the matrix and the fibers. Also, when a strengthening system is applied to a concave masonry substrate, the additional stress component (normal to the substrate) at the matrix–substrate and matrix–fiber interface, due to the substrate curvature, negatively effects the stress-transfer mechanism between the strengthening system and the masonry substrate. In current engineering practice, spike anchors are generally used to improve bonding properties between the composite material and the substrate in order to reduce the negative effects of a strengthening system applied to a concave masonry/concrete substrate. In this paper, we report and discuss the results obtained from direct shear tests performed on an FRCM with a pozzolanic reaction on strengthened curved masonry specimens. In particular, the experimental campaign revealed the effects of spike anchors in the stress-transfer mechanism between the FRCM and the masonry substrate. The presence of spike anchors, as we determined, caused local effects that altered the stress-transfer mechanism. However, the maximum force obtained from single shear-lap tests on specimens with spike anchors was, on average, higher than that obtained from specimens without spike anchors.
Get full access to this article
View all available purchase options and get full access to this article.
Data Availability Statement
Some data used in the study are proprietary or confidential in nature and may only be provided with restrictions (in particular, the points of the curves for Figs. 6(a–d), 8(a and b), 11(a–c), 12, 13(a and b), 15(a and b), 16(a and b), and 23 can be provided only in a strictly confidential way).
Notation
The following symbols are used in this paper:
- Af
- fiber area;
- a
- brick width;
- b
- brick length;
- C
- resultant of compressive stresses;
- c
- brick height;
- d
- equivalent fiber bundle height;
- Ef
- elastic modulus obtained from tensile test of bare fiber;
- FC
- axial resistant force of connectors;
- fm
- design compressive stress of masonry;
- Lc1
- when la = b;
- Lc2
- when la = b/2;
- la
- spike anchor depth;
- lb
- bonded length;
- lb,eff
- effective bonded length;
- MR
- resistant moment of strengthened section;
- n
- number of fiber bundles;
- na
- number of spike anchors;
- P
- load value;
- Pc1
- when na = 1;
- Pc2
- when na = 2;
- R
- radius of curvature;
- Sg
- global slip;
- T
- resultant tensile stress;
- t
- equivalent fiber bundle width;
- tFRCM
- thickness of strengthening;
- t1
- minimum mortar joint thickness;
- t2
- maximum mortar joint thickness;
- W
- indication of dry or impregnated fiber;
- wb
- bonded width;
- y
- curvilinear abscissa of the reinforcement;
- ysa
- curvilinear abscissa of the spike anchor;
- Z
- specimen number;
- α
- amplification factor that takes into account the stress difference between the shear-lap test and reinforced arch experiments;
- dimensionless strain;
- ɛfe
- effective strain;
- ɛum
- final strain of masonry;
- θ
- angle between the two radii for y = 0 and y = lb;
- σdeb
- debonding stress;
- external normal stress component;
- σfe
- maximum fiber stress;
- internal normal stress component;
- σyy
- axial stress;
- dimensionless stress;
- σ*
- maximum stress of the bond capacity between the substrate and the FRCM;
- external tangential stress component; and
- internal tangential stress component.
References
Alabdulhady, M. Y., L. H. Sneed, and C. Carloni. 2017. “Torsional behavior of RC beams strengthened with PBO-FRCM composite – An experimental study.” Eng. Struct. 136: 393–405. https://doi.org/10.1016/j.engstruct.2017.01.044.
Alecci, V., F. Focacci, L. Rovero, G. Stipo, and M. De Stefano. 2017. “Intrados strengthening of brick masonry arches with different FRCM composites: Experimental and analytical investigations.” Compos. Struct. 176: 898–909. https://doi.org/10.1016/j.compstruct.2017.06.023.
Awani, O., A. El Refai, and T. El-Maaddawy. 2015. “Bond characteristics of carbon fabric-reinforced cementitious matrix in double shear tests.” Constr. Build. Mater. 101 (1): 39–49. https://doi.org/10.1016/j.conbuildmat.2015.10.017.
Azam, R., and K. Soudki. 2014. “FRCM strengthening of shear-critical RC beams.” J. Compos. Constr. 18 (5): 04014012. https://doi.org/10.1061/(ASCE)CC.1943-5614.0000464.
Bakis, C. E., L. C. Bank, V. L. Brown, E. Cosenza, J. F. Davalos, J. J. Lesko, A. Machida, S. H. Rizkalla, and T. C. Triantafillou. 2002. “Fiber-reinforced polymer composites for construction—State-of-the-art review.” J. Compos. Constr. 6 (2): 73–87. https://doi.org/10.1061/(ASCE)1090-0268(2002)6:2(73).
Bertolesi, E., M. Fagone, T. Rotunno, E. Grande, and G. Milani. 2022. “Experimental characterization of the textile-to-mortar bond through distributed optical sensors.” Constr. Build. Mater. 326: 126640. https://doi.org/10.1016/j.conbuildmat.2022.126640.
Bertolesi, E., E. Grande, M. Fagone, G. Milani, and T. Rotunno. 2021. “Mechanical model based on a BVP for FRPs applied on flat and curved masonry pillars with anchor spikes.” Compos. Struct. 273: 114251. https://doi.org/10.1016/j.compstruct.2021.114251.
Bertolesi, E., G. Milani, M. Fagone, T. Rotunno, and E. Grande. 2020. “Heterogeneous FE model for single lap shear tests on FRP reinforced masonry curved pillars with spike anchors.” Constr. Build. Mater. 258: 119629. https://doi.org/10.1016/j.conbuildmat.2020.119629.
Bisby, L., T. Stratford, C. Hart, and S. Farren. 2013. “Fire performance of well-anchored TRM, FRCM and FRP flexural strengthening systems.” In Proc., 6th Int. Conf. on Advance Composite in Construction, 98–109. Chesterfield, UK: Network Group for Composites in Construction.
Blanksvärd, T., B. Täljsten, and A. Carolin. 2009. “Shear strengthening of concrete structures with the use of mineral-based composites.” J. Compos. Constr. 13 (1): 25–34. https://doi.org/10.1061/(ASCE)1090-0268(2009)13:1(25).
Bournas, D. A., P. V. Lontou, C. G. Papanicolaou, and T. C. Triantafillou. 2007. “Textile-reinforced mortar versus fiber-reinforced polymer confinement in reinforced concrete columns.” ACI Struct. J. 104 (6): 740–748.
Cabral-Fonseca, S., J. R. Correia, J. Custódio, H. M. Silva, A. M. Machado, and J. Sousa. 2018. “Durability of FRP–concrete bonded joints in structural rehabilitation: A review.” Int. J. Adhes. Adhes. 83: 153–167. https://doi.org/10.1016/j.ijadhadh.2018.02.014.
Calabrese, A. S., P. Colombi, and T. D’Antino. 2019. “Analytical solution of the bond behavior of FRCM composites using a rigid-softening cohesive material law.” Composites, Part B 174: 107051. https://doi.org/10.1016/j.compositesb.2019.107051.
Calabrese, A. S., T. D’Antino, P. Colombi, and C. Poggi. 2020. “Study of the influence of interface normal stresses on the bond behavior of FRCM composites using direct shear and modified beam tests.” Constr. Build. Mater. 262: 120029. https://doi.org/10.1016/j.conbuildmat.2020.120029.
Carloni, C. 2014. “Analyzing bond characteristics between composites and quasi-brittle substrates in the repair of bridges and other concrete structures.” In Advanced composites in bridge construction and repair, edited by Y. J. Kim, 61–93. Cambridge, UK: Woodhead Publishing.
Carozzi, F. G., P. Colombi, G. Fava, and C. Poggi. 2016. “A cohesive interface crack model for the matrix–textile debonding in FRCM composites.” Compos. Struct. 143: 230–241. https://doi.org/10.1016/j.compstruct.2016.02.019.
Cerniauskas, G., Z. Tetta, D. A. Bournas, and L. A. Bisby. 2020. “Concrete confinement with TRM versus FRP jackets at elevated temperatures.” Mater. Struct. 53 (3): 1–14. https://doi.org/10.1617/s11527-020-01492-x.
CNR (National Research Council). 2019. Guide for the design and construction of externally bonded fibre reinforced inorganic matrix systems for strengthening existing structures. CNR-DT 215/2018. Rome, Italy: CNR.
D’Ambra, C., G. P. Lignola, A. Prota, E. Sacco, and F. Fabbrocino. 2018. “Experimental performance of FRCM retrofit on out-of-plane behaviour of clay brick walls.” Composites, Part B 148: 198–206. https://doi.org/10.1016/j.compositesb.2018.04.062.
D’Ambrisi, A., L. Feo, and F. Focacci. 2012. “Bond-slip relations for PBO-FRCM materials externally bonded to concrete.” Composites, Part B 43 (8): 2938–2949. https://doi.org/10.1016/j.compositesb.2012.06.002.
D’Ambrisi, A., and F. Focacci. 2011. “Flexural strengthening of RC beams with cement-based composites.” J. Compos. Constr. 15 (5): 707–720. https://doi.org/10.1061/(ASCE)CC.1943-5614.0000218.
D’Antino, T., C. Carloni, L. Sneed, and C. Pellegrino. 2014. “Matrix–fiber bond behavior in PBO FRCM composites: A fracture mechanics approach.” Eng. Fract. Mech. 117: 94–111. https://doi.org/10.1016/j.engfracmech.2014.01.011.
D’Antino, T., P. Colombi, C. Carloni, and L. H. Sneed. 2018. “Estimation of a matrix-fiber interface cohesive material law in FRCM–concrete joints.” Compos. Struct. 193: 103–112. https://doi.org/10.1016/j.compstruct.2018.03.005.
D’Antino, T., F. Focacci, L. H. Sneed, and C. Pellegrino. 2020. “Shear strength model for RC beams with U-wrapped FRCM composites.” J. Compos. Constr. 24 (1): 04019057. https://doi.org/10.1061/(ASCE)CC.1943-5614.0000986.
D’Antino, T., and C. Poggi. 2019. “Stress redistribution in glass fibers of G-FRCM composites.” Key Eng. Mater. 817: 520–527. https://doi.org/10.4028/www.scientific.net/KEM.817.520.
D’Antino, T., and C. Poggi. 2021. “Characterization and design of multilayer PBO FRCM composite reinforcements for concrete structures.” J. Compos. Constr. 25 (6): 04021048. https://doi.org/10.1061/(ASCE)CC.1943-5614.0001155.
D’Antino, T., L. H. Sneed, C. Carloni, and C. Pellegrino. 2016. “Effect of the inherent eccentricity in single-lap direct-shear tests of PBO FRCM–concrete joints.” Compos. Struct. 142: 117–129. https://doi.org/10.1016/j.compstruct.2016.01.076.
de Felice, G., S. De Santis, L. Garmendia, B. Ghiassi, P. Larrinaga, P. B. Lourenço, D. V. Oliveira, F. Paolacci, and C. G. Papanicolaou. 2014. “Mortar-based systems for externally bonded strengthening of masonry.” Mater. Struct. 47 (12): 2021–2037. https://doi.org/10.1617/s11527-014-0360-1.
del Rey Castillo, E., K. A. Harries, R. Rogers, and R. Kanitkar. 2022. “FRP tension ties: State-of-the-art review of existing design guidance for debonding capacity and applicability to concrete diaphragm seismic strengthening.” J. Compos. Constr. 26 (2): 04022014. https://doi.org/10.1061/(ASCE)CC.1943-5614.0001191.
del Rey Castillo, E., R. Kanitkar, S. T. Smith, and M. C. Griffith. 2019. “Design approach for FRP spike anchors in FRP-strengthened RC structures.” Compos. Struct. 214: 23–33. https://doi.org/10.1016/j.compstruct.2019.01.100.
De Maio, U., F. Fabbrocino, F. Greco, L. Leonetti, and P. Lonetti. 2019. “A study of concrete cover separation failure in FRP-plated RC beams via an inter-element fracture approach.” Compos. Struct. 212: 625–636. https://doi.org/10.1016/j.compstruct.2019.01.025.
De Santis, S. 2017. “Bond behaviour of steel reinforced grout for the extrados strengthening of masonry vaults.” Constr. Build. Mater. 150: 367–382. https://doi.org/10.1016/j.conbuildmat.2017.06.010.
Focacci, F., T. D’Antino, C. Carloni, L. H. Sneed, and C. Pellegrino. 2017. “An indirect method to calibrate the interfacial cohesive material law for FRCM–concrete joints.” Mater. Des. 128: 206–217. https://doi.org/10.1016/j.matdes.2017.04.038.
Foster, S., and L. Bisby. 2008. “Fire survivability of externally bonded FRP strengthening systems.” J. Compos. Constr. 12 (5): 553–561. https://doi.org/10.1061/(ASCE)1090-0268(2008)12:5(553).
Galassi, S. 2018a. “A numerical procedure for failure mode detection of masonry arches reinforced with fiber reinforced polymeric materials.” IOP Conf. Ser.: Mater. Sci. Eng. 369: 012038. https://doi.org/10.1088/1757-899X/369/1/012038.
Galassi, S. 2018b. “Analysis of masonry arches reinforced with FRP sheets: Experimental results and numerical evaluations.” In Vol. 207 of MATEC Web of Conf., Les Ulis, France: EDP Sciences.
Gonzalez-Libreros, J., L. Sneed, T. D’Antino, and C. Pellegrino. 2017. “Behavior of RC beams strengthened in shear with FRP and FRCM composites.” Eng. Struct. 150: 830–842. https://doi.org/10.1016/j.engstruct.2017.07.084.
Grande, E., and G. Milani. 2021. “Modeling of FRCM strengthening systems externally applied on curved masonry substrates.” Eng. Struct. 233: 111895. https://doi.org/10.1016/j.engstruct.2021.111895.
He, R., S. Grelle, L. H. Sneed, and A. Belarbi. 2013. “Rapid repair of a severely damaged RC column having fractured bars using externally bonded CFRP.” Compos. Struct. 101: 225–242. https://doi.org/10.1016/j.compstruct.2013.02.012.
Hollaway, L. 2010. “A review of the present and future utilisation of FRP composites in the civil infrastructure with reference to their important in-service properties.” Constr. Build. Mater. 24 (12): 2419–2445. https://doi.org/10.1016/j.conbuildmat.2010.04.062.
Kalfat, R., R. Al-Mahaid, and S. T. Smith. 2013. “Anchorage devices used to improve the performance of reinforced concrete beams retrofitted with FRP composites: State-of-the-art review.” J. Compos. Constr. 17 (1): 14–33. https://doi.org/10.1061/(ASCE)CC.1943-5614.0000276.
Liu, S., S. Yin, and L. Jing. 2021. “Fracture energy analysis on the fabric–matrix interface for the bond system of fabric-reinforced cementitious matrix (FRCM)–masonry substrate.” Compos. Interfaces 28 (12): 1203–1220. https://doi.org/10.1080/09276440.2020.1870190.
Malena, M. 2018. “Closed-form solution to the debonding of mortar based composites on curved substrates.” Composites, Part B 139: 249–258. https://doi.org/10.1016/j.compositesb.2017.11.044.
Malena, M., and G. de Felice. 2014. “Debonding of composites on a curved masonry substrate: Experimental results and analytical formulation.” Compos. Struct. 112: 194–206. https://doi.org/10.1016/j.compstruct.2014.02.004.
Mandor, A., and A. El Refai. 2021. “Assessment and modeling of the debonding failure of fabric-reinforced cementitious matrix (FRCM) systems.” Compos. Struct. 275: 114394. https://doi.org/10.1016/j.compstruct.2021.114394.
Raoof, S. M., and D. A. Bournas. 2017. “TRM versus FRP in flexural strengthening of RC beams: Behaviour at high temperatures.” Constr. Build. Mater. 154: 424–437. https://doi.org/10.1016/j.conbuildmat.2017.07.195.
Rotunno, T., M. Fagone, E. Bertolesi, E. Grande, and G. Milani. 2018. “Single lap shear tests of masonry curved pillars externally strengthened by CFRP strips.” Compos. Struct. 200: 434–448. https://doi.org/10.1016/j.compstruct.2018.05.097.
Rotunno, T., M. Fagone, E. Bertolesi, E. Grande, and G. Milani. 2019. “Curved masonry pillars reinforced with anchored CFRP sheets: An experimental analysis.” Composites, Part B 174: 107008. https://doi.org/10.1016/j.compositesb.2019.107008.
Sabau, C., J. H. Gonzalez-Libreros, L. H. Sneed, G. Sas, C. Pellegrino, and B. Täljsten. 2017. “Use of image correlation system to study the bond behavior of FRCM–concrete joints.” Mater. Struct. 50 (3): 172. https://doi.org/10.1617/s11527-017-1036-4.
Simoncello, N., P. Zampieri, J. Gonzalez-Libreros, S. Perboni, and C. Pellegrino. 2020. “Numerical analysis of an FRP-strengthened masonry arch bridge.” Front. Built Environ. 6: 7. https://doi.org/10.3389/fbuil.2020.00007.
Simoncello, N., P. Zampieri, M. Zizi, L. Rossi, and C. Pellegrino. 2022. “Lateral response of damaged stand-alone arches: Tilting tests and rigid-block analysis.” Eng. Struct. 268: 114700. https://doi.org/10.1016/j.engstruct.2022.114700.
Teng, J., J. Chen, S. Smith, and L. Lam. 2001. FRP: Strengthened RC structures. Chichester, UK: Wiley.
Trapko, T. 2013. “The effect of high temperature on the performance of CFRP and FRCM confined concrete elements.” Composites, Part B 54: 138–145. https://doi.org/10.1016/j.compositesb.2013.05.016.
Wang, F., N. Kyriakides, C. Chrysostomou, E. Eleftheriou, R. Votsis, and R. Illampas. 2021. “Experimental research on bond behaviour of fabric reinforced cementitious matrix composites for retrofitting masonry walls.” Int. J. Concr. Struct. Mater. 15 (1): 22. https://doi.org/10.1186/s40069-021-00460-1.
Yang, Y., L. Sneed, M. S. Saiidi, A. Belarbi, M. Ehsani, and R. He. 2015. “Emergency repair of an RC bridge column with fractured bars using externally bonded prefabricated thin CFRP laminates and CFRP strips.” Compos. Struct. 133: 727–738. https://doi.org/10.1016/j.compstruct.2015.07.045.
Zampieri, P. 2020. “Horizontal capacity of single-span masonry bridges with intrados FRCM strengthening.” Compos. Struct. 254: 112238. https://doi.org/10.1016/j.compstruct.2020.112238.
Zampieri, P., N. Simoncello, J. Gonzalez-Libreros, and C. Pellegrino. 2020. “Evaluation of the vertical load capacity of masonry arch bridges strengthened with FRCM or SFRM by limit analysis.” Eng. Struct. 225: 111135. https://doi.org/10.1016/j.engstruct.2020.111135.
Zhao, J., G. Cai, L. Cui, A. Si Larbi, and K. Daniel Tsavdaridis. 2017. “Deterioration of basic properties of the materials in FRP-strengthening RC structures under ultraviolet exposure.” Polymers 9 (12): 402. https://doi.org/10.3390/polym9090402.
Zou, X., T. D’Antino, and L. H. Sneed. 2021. “Investigation of the bond behavior of the fiber reinforced composite–concrete interface using the finite difference method (FDM).” Compos. Struct. 278: 114643. https://doi.org/10.1016/j.compstruct.2021.114643.
Zou, X., L. H. Sneed, and T. D’Antino. 2020. “Full-range behavior of fiber reinforced cementitious matrix (FRCM)–concrete joints using a trilinear bond-slip relationship.” Compos. Struct. 239: 112024. https://doi.org/10.1016/j.compstruct.2020.112024.
Zou, X., L. H. Sneed, T. D’Antino, and C. Carloni. 2019. “Analytical bond-slip model for fiber-reinforced cementitious matrix–concrete joints based on strain measurements.” J. Mater. Civ. Eng. 31 (11): 04019247. https://doi.org/10.1061/(ASCE)MT.1943-5533.0002855.
Information & Authors
Information
Published In
Journal of Composites for Construction
Volume 27 • Issue 6 • December 2023
Copyright
© 2023 American Society of Civil Engineers.
History
Received: Oct 25, 2022
Accepted: Aug 7, 2023
Published online: Oct 13, 2023
Published in print: Dec 1, 2023
Discussion open until: Mar 13, 2024
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.