Issue 58

M. Emara et alii, Frattura ed Integrità Strutturale, 58 (2021) 48-64; DOI: 10.3221/IGF-ESIS.58.04

by Al-Farttoosi, Mahdi [18] to perform the experimental work to study the impact behavior of the CFRP strengthened concrete beams. To strengthen the RC beams, externally bonded reinforcement (EBR) was used. The width and height of the beams measured were 150 mm and 200 mm respectively and 3150mm long with a clear span of 3000 mm. The results indicated that the force of impact encountered by the strengthened beams was lower than that of the control beam. CFRP increased the beam stiffness in strengthened beams, decreased the width of the cracks and their propagation, and decreased both the deformation of the beam and the number of cracks. Under impact loading, the CFRP significantly reduced the residual deflection and maximum deflection of the reinforced beams. The use of CFRP to strengthen the beams diminished the beams' ductility and increased the risk of their sudden failure. Pham and Hao [19] investigated the behavior of reinforced concrete beams strengthened with fiber-reinforced polymers under impact loads. The experimental program included a control beam (RB) and strengthened one (NL1B) tested under impact loads. Longitudinal fiber-reinforced polymer strips were used to strengthen the beam. The experimental results showed that the strengthened beam with CFRP layer is better than the control beam against impact loads. From the analysis of the available literature, it can be concluded that the Finite Element Analysis (FEA) can be considered as a reliable alternative to the expensive and time-consuming experimental approach. Moreover, more research still required to investigate the behavior of RC beams strengthened with FRP materials. For this, this paper investigates numerically the flexural response of RC beams strengthened using CFRP sheets under impact loading. A three-dimensional Finite Element Model (FEM) was developed, and the obtained results were validated against experimental results available in the literature. Then a parametric study was performed considering the flexural reinforcement type, the diameter of reinforcing steel rebars, CFRP sheet width, and the bonded length of the CFRP.

(a)

(b) Figure 1: Details of CFRP strengthened RC beam specimens [19]: (a) Longitudinal section, and (b) Cross-sections.

E XPERIMENTAL WORK

n experimental study available in the literature [19] was used to verify and validate the numerical model. In this study, a series of CFRP strengthened RC beams were tested under impact load. The rectangular beam had dimensions of 150 mm, 250 mm and 2200 mm for the width, height and total length, respectively, with a clear span of 1900 mm between supports as shown in Fig. 1. At 28 days of age, the concrete compressive strength was 46 MPa. Two steel bars with a diameter of 12 mm were used at the top of the beam, while two steel bars with a diameter of 10 mm were used to reinforce the bottom of the beam. For shear reinforcement, 10 mm steel bars were used. For the total beam length, A

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