Issue 67

M. A. Nasser et alii, Frattura ed Integrità Strutturale, 67 (2023) 319-336; DOI: 10.3221/IGF-ESIS.67.23

[20] Parretti, R., and Nanni, A. (2004) Strengthening of RC members using near-surface-mounted FRP composites: Design overview. Advanced in Structural Engineering, 7(6), pp. 469-483. [21] Täljsten, B., Carolin, A., and Nordin, H. (2001). Concrete beams strengthened with near-surface-mounted CFRP laminates. In Proceedings of CFRPCS-5, C. Burgoyne (ed.). Cambridge, UK, pp. 107-116. [22] Täljsten, B., Carolin, A. and Nordin, H. (2003). Concrete structures strengthened with near-surface-mounted reinforcement of CFRP. Advanced in Structural Engineering, 6(3), pp. 201-221. DOI: 10.1260/136943303322419223 [23] El-Hacha,R., and Rizkalla, S.H. (2004). Near-surface-mounted fiber-reinforced polymer reinforcements for flexural strengthening of concrete structures. ACI Structural Journal, 101(5), pp. 830-839. DOI: 10.14359/13394 [24] Egyptian Code of Practice for Design and Construction of Reinforced Concrete Structures, ECP-203. (2019). Housing, and Building Research Center, Ministry of Building and Construction, Giza, Egypt, Chapter 6,113-122. [25] ASTM D790-02. (1998). Standard Test Methods for Flexural Properties of Unreinforced and Reinforced Plastics and Electrical Insulating Materials, American Society of Mechanical Engineering, New York. DOI: 10.1520/D0790-02 [26] ASTM International (2021): Standard test method for static modulus of elasticity and Poisson ratio of concrete in compression, ASTM C469/C469M-14, West Conshohocken. DOI: 10.1520/C0469_C0469M-14. [27] ASTM International (2015): Standard test method for splitting tensile strength of cylinder concrete specimens, ASTM C496-96. DOI: 10.1520/C0496-96 [28] ASTM International (2015): Standard test method for compressive strength of cylindrical concrete specimens, ASTM C39/ C39M–14. DOI: 10.1520/C0039 C0039 M-14 [29] ASTM D7205 Tensile Tests of GFRP Matrix Composite Bars [30] ACI Committee 318-19. (2019). Building Code Required for Reinforced Concrete, (ACI 318-19) and Commentary (ACI 318R-19), American Concrete Institute, Farmington Hills, Mich. DOI: 10.14359/51716937 [31] CSA-A23.3-04, (2004), Design of Concrete Structures for Buildings, Canadian Standards Association, Rexdale, Ontario, Canada. 240 p. : Shear span - the distance from the load to the support (400, 450, and 600 mm); b : Specimen width (constant at 400 mm); d : Specimen effective depth (= total depth –concrete cover (25 mm) =575 mm (constant)); t : Specimen depth = 600 mm (constant); L 0 : Specimen’s clear span (constant at 2000 mm); a/t : Shear-span to total depth ratio (0.67, 0.75, and 1.0); e : Eccentricity of the applied load from the center of the specimen axis; A s : Area of GFRP bars in tension (constant at 8 Φ 12); A s ` : Area of GFRP bars in compression (constant at 4 Φ 8); f cu : Cubic concrete characteristic compressive strength of 25 MPa; f c ` : Cylindrical concrete characteristic compressive strength (20 MPa); GFRP: Glass Fiber Reinforced Plastic; P i : First crack load before retrofitting; P fR : Failure load after retrofitting; ∆ f i : Displacement at mid-span at failure load before retrofitting; ∆ fR : Displacement at mid-span at failure load after retrofitting; S.S : Secant stiffness (N/mm) P fR / ∆ fR ; D.D : Displacement ductility is the ratio of the deflection at 90% of the failure load in the descending branch to that in the ascending branch; and T : Toughness is the ability to adsorb deformations up to failure, which equals the area under the load deflection curve up to failure. N OMENCLATURE a

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