PSI - Issue 28

Haya H. Mhanna et al. / Procedia Structural Integrity 28 (2020) 811–819 Mhanna et al./ Structural Integrity Procedia 00 (2020) 000–000

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respect to specimen BSU at ultimate and failure loads is also presented in Table 2. It is evident from Table 2 that the ductility of the two control specimens BSU and C are comparable indicating that strengthening without anchorage resulted in a brittle type of failure. It is also apparent that the ductility of the anchored specimens surpassed the ductility of the unanchored specimen in the range of 1.42 – 2.98 at ultimate state and 1.7 – 3.20 at failure. The highest ductility was exhibited by specimen BSD14, with a ductility index of 3.54 and 4.42 at ultimate and failure loads, respectively. µ �� � � � � � (1) µ �� � � � � � (2) Table 2. Ductility results.

Specimen

μ Δ u

μ Δ f

μ Δ u / μ Δ u (BSU)

μ Δ f / μ Δ f (BSU)

C

1.19 1.19 1.68 3.54 2.94

1.30 1.38 2.35 4.42 4.03

-

-

BSU

1

1

BSD12 BSD14 BSD16

1.42 2.98 2.48

1.70 3.20 2.92

5. Conclusion This paper presented an experimental investigation to examine the effect of strengthening shear deficient RC T beams with CFRP U-wrapped laminates anchored with CFRP splay anchors. The parameter investigated in this study is the anchor dowel diameter. From the experimental test results, the following conclusions could be drawn: 1. Shear strengthening with CFRP U-wrapped laminates enhances the shear capacity. However, failure is dominated by the brittle debonding of the laminates. 2. Anchoring the U-wrapped laminates with CFRP splay anchors delayed debonding of the U-wraps, improved the shear strength of unanchored U-wraps, and significantly enhanced the ductility of the beam specimens. 3. Anchoring CFRP laminates by CFRP anchors highly utilized the strain levels attained in CFRP laminates, compared to the unanchored specimen. 4. No clear trend was observed between anchor diameter and the ultimate load-carrying capacity of the specimens. 5. Anchor dowel diameter of 14 mm was found optimum for an anchor embedment depth of 85 mm. References Abuodeh, O. R., Abdalla, J. A., Hawileh, R. A., 2020. Prediction of shear strength and behavior of RC beams strengthened with externally bonded FRP sheets using machine learning techniques. Composite Structures, 234, 111698. Ali, A., Abdalla, J., Hawileh, R., & Galal, K., 2014. CFRP mechanical anchorage for externally strengthened RC beams under flexure. Physics Procedia, 55, pp. 10–16. Bae, S., Belarbi, A., 2013. Behavior of Various Anchorage Systems Used for Shear Strengthening of Concrete Structures with Externally Bonded FRP Sheets. Journal of Bridge Engineering, 18, 9, pp. 837–847. Castillo, E., Dizhur, D., Griffith, M., & Ingham, J., 2019. Strengthening RC structures using FRP spike anchors in combination with EBR systems. Composite Structures, 209, pp. 668–685. Castillo, E., Kanitkar, R., Smith, S. T., Griffith, M. C., Ingham, J. M., 2019. Design approach for FRP spike anchors in FRP-strengthened RC structures. Composite Structures, 214, pp. 23–33. Choobbor, S. S., Hawileh, R. A., Abu-obeidah, A., Abdalla, J. A., 2019. Performance of hybrid carbon and basalt FRP sheets in strengthening concrete beams in fl exure. Composite Structures, 227, 111337. Eshwar, N., Nanni, A., Ibell, T. J., 2008. Performance of Two Anchor Systems of Externally Bonded Fiber-Reinforced Polymer Laminates. ACI Materials Journal, 105, 1, pp. 72–81.