Epoxy bonding a thin layer of composite materials to the exterior surfaces of unreinforced masonry (URM) walls forces the individual brick or block elements to act as an integrated system. The high tensile strength of composite materials can be utilized to increase the shear and flexural capacity of URM walls significantly. This article presents the results of the experimental work carried out to investigate the capability of glass fiber reinforced polymer (GFRP) laminates in strengthening the concrete block walls subjected to out-of-plane and in-plane vertical and lateral stresses. A significant strength increase was observed for all strengthened specimens. Based on deformation compatibility and force equilibrium, simple design equations are presented to estimate the strength of masonry walls and their possible mode of failure. An excellent agreement between measured and predicted values of ultimate strength of wall specimens has been observed.

ACI Committee 440 (October 2001). Guide for the Design and Construction of Externally Bonded FRP Systems for Strengthening Concrete Structures, American Concrete Institute, Detroit, Michigan . Google Scholar
Al-Saidy, A. , Ehsani, M. R. and Saadatmanesh, H. (1996). Strengthening of URM Walls for Direct Shear , In: Proceedings of the 2nd International Conference on Advanced Composite Materials in Bridges and Structures (ACMBS’96), Montreal, Quebec, Canada, August, pp. 605-612 . Google Scholar
American Concrete Institute , (1997). ACI Manual of Concrete Practice Part 5, Farmington Hills, MI 48333-9094 . Google Scholar
Baker, L. R. (1978). Precracking Behavior of Laterally Loaded Brickwork Panels with In-plane Restrains , In: Proceedings of the British Ceramic Society, No. 27, pp. 129-146 . Google Scholar
(1994). Design of Masonry Structures, Eurocode No. 6, Comite Euro-International du Beton, Lausanne, France . Google Scholar
Ehsani, M. R. and Saadatmanesh, H. (1996). Repair and Strengthening of Earthquake-Damaged Concrete and Masonry Walls with Composite Fabrics , In: First International Conference on Fiber Composites in Infrastructures, ICCI’96, Tucson, Arizona, January, pp. 1156-1167 . Google Scholar
Ehsani, M. R. , Saadatmanesh, H. and Velazquez-Dimas, J. I. (August 1999). Behavior of Retrofitted URM Walls under Simulated Earthquake Loading , Journal of Composites for Construction, ASCE, 3(3): 134-142 . Google Scholar, Crossref
Hamilton III, H. R. , Holberg, A. , Caspersen, J. and Dolan, C. W. (1999). Strengthening Concrete Masonry with Fiber Reinforced Polymers , In: Fourth International Symposium on Fiber Reinforced Polymer (FRP) for Reinforced Concrete Structures, Baltimore, Maryland, November, pp. 1103-1115 . Google Scholar
Hamilton III, H. R. and Dolan, C. W. (2001). Flexural Capacity of Glass FRP Strengthened Concrete Masonry Walls , Journal of Composites for Construction, ASCE, 5(3): 170-178 . Google Scholar, Crossref
Hartley, A. , Mullins, G. and Sen, R. (1996). Repair of Concrete Masonry Block Walls using Carbon Fiber , In: Proceedings of the Second International Conference on Advanced Composite Materials in Bridges and Structures, Montreal, Quebec, Canada, August, pp. 795-802 . Google Scholar
Hendry, A. W. (1981). Structural Brickwork, pp. 128 and 141, The Macmillan Press Ltd., London . Google Scholar, Crossref
Kuzik, M. D. , Elwi, A. E. and Cheng, J.J. R. (2003). Cyclic Flexure Tests of Masonry Walls Reinforced with Glass Fiber Reinforced Polymer Sheets , Journal of Composites for Construction, ASCE, 7(1): 20-30 . Google Scholar, Crossref
Laursen, P. T. , Seible, F. , Hegemier, G. A. and Innamorato, D. (1995). Seismic Retrofit and Repair of Masonry Walls with Carbon Overlays, In: Taerwe, L. (ed.), Non-Metallic (FRP) Reinforcement for Concrete Structures, pp. 616-627, RILEM . Google Scholar
Muszynsky, L. C. (1998). Explosive Field Tests to Evaluate Composite Reinforcement of Concrete and Masonry Walls , In: Second International Conference on Composites in Infrastructures, Tucson, Arizona, pp. 276-284 . Google Scholar
Railway Technical Research Institute (1996). Recommendation for Design and Construction Practice of Reinforced Concrete Railway Viaduct Column Retrofitted by Carbon Fiber Sheet, Japan . Google Scholar
Roko, K. , Boothby, T. E. and Bakis, C. E. (1999). Failure Modes of Sheet Bonded Fiber Reinforced Polymer Applied to Brick Masonry , In: Fourth International Symposium on Fiber Reinforced Polymer (FRP) for Reinforced Concrete Structures, Baltimore, Maryland, November, pp. 305-311 . Google Scholar
Schwegler, G. (1995). Masonry Construction Strengthened with Fiber Composites in Seismically Endangered Zones , In: Proceedings of the Tenth European Conference on Earthquake Engineering, Rotterdam, pp. 2299-2303 . Google Scholar
Schwegler, G. and Kelterborn, P. (1996). Earthquake Resistance of Masonry Structures Strengthened with Fiber Composites , In: Eleventh World Conference on Earthquake Engineering, Acapulco, Mexico. Google Scholar
Triantafillou, T. C. (1996). Innovation Strengthening of Masonry Monuments with Composites , In: Proceedings of the Second International Conference on Advanced Composite Materials in Bridges and Structures, Montreal, Quebec, Canada, August, pp. 473-480 . Google Scholar
Triantafillou, T. C. (May 1998). Strengthening of Masonry Structures Using Epoxy-Bonded FRP Laminates , Journal of Composites for Construction, ASCE, 2(2): 96-104 . Google Scholar, Crossref
Triantafillou, T. C. and Antonopoulos, C. P. (1999). Design of Concrete Member Strengthened in Shear with Fiber Reinforced Polymer Materials , In: Proceedings of the Fourth International Symposium on Non-Metallic (FRP) Reinforcement for Concrete Structures, Baltimore, Maryland, Oct. 31-Nov. 5. Google Scholar
Tumialan, J.G. (2001). Strengthening of Masonry Structures with FRP Composites, Doctoral Dissertation, University of Missouri-Rolla, Rolla, Missouri. Google Scholar
Tumialan, J. G. , Tinazzi, D. , Myers, J. and Nanni, A. (2000). Field Evaluation of Unreinforced Masonry Walls Strengthened with FRP Composites Subjected to Out-of-Plane Loading , In: 2000 Structures Congress, Philadelphia, Pennsylvania, May, American Society of Civil Engineers. Google Scholar, Crossref
Velazquez, J.I. (1998). Out-of-Plane Cyclic Behavior of URM Walls Retrofitted with Fiber Composites, PhD Dissertation, Department of Civil Engineering and Engineering Mechanics, The University of Arizona. Google Scholar
Velazquez, J. I. , Ehsani, M. R. and Saadatmanesh, H. , (May-June 2000). Out-of-Plane Behavior of Brick Masonry Walls Strengthened with Fiber Composites , ACI Structural Journal, 97(3): 377-387 . Google Scholar

Vol 39, Issue 19, 2005