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SUMMARY Using externally bonded carbon fiber‐reinforced polymer (FRP) for strengthening has been turned into a popular decision owing to its mechanical leads. Consequently, design guidelines and researchers have established several analytical equations to predict the contribution of FRP to ultimate shear capacity. The developed analytical equations projected the influence of FRP reinforcements within certain limits. However, not mentioned parameters such as the shear span‐to‐depth ratio and anchorage application influence the ultimate behavior of strengthened specimens. Accordingly, distant predictions between test results and code predictions are observed for the specimens in whom anchorage is applied. As an alternative method, artificial neural network (NN) can be used to predict the contribution of anchoraged carbon FRP to shear strength of deficient reinforced concrete beams. Accordingly, two NN models with back‐propagation are developed in this study. Unlike the existing design codes, the model considers the effect of anchorage and the shear span‐to‐depth ratio at the ultimate state. Artificial NN model is trained, validated and tested using the literature of 79 reinforced concrete beams. Then, NN results are compared with those ‘theoretical’ predictions calculated directly from International Federation for Structural Concrete, the American guideline (ACI 440.2R) and the Australian guideline. Within all theoretical predictions of design guidelines, fib14 provided the best predictions according to experimental results. Consequently, 25% of fib14 predictions are within ±10% of the experimental results, and also, 65% of the fib14 predictions are within ±25% of the measured values. Besides, executed comparisons indicated that the NN model is more exact than the guideline equations with respect to the experimental results and can be applied effectively within the range of parameters covered in this study. Copyright © 2014 John Wiley & Sons, Ltd.

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An experimental investigation was conducted to study the effect of composite carbon fabric shear reinforcement on the ultimate strength and behaviour of reinforced concrete beam. Shear deficient specimens were strengthened by using side-bonded and wrapped CFRP straps. Eight beams were fabricated and tested under the cyclic loads. The main objective of the study is to obtain ductile flexural behaviour from the shear deficient RC beams. To verify the reliability of shear design equations and guidelines, experimental results were compared with all common guidelines and published design equations.

The aim of this experimental study was to investigate the behaviour of reinforced concrete (RC) T-section beams that were strengthened by carbon fibre reinforced polymer (CFRP) plates. Six specimens, one of which was the control specimen and five of which were the shear deficient test specimens, were strengthened with side-bonded and t -jacketed CFRP plates. Unidirectional and bidirectional CFRP sheets were used as strengthening material. Distinct CFRP type, CFRP arrangement, number of sheet layers and wrapping schemes were the variables that were investigated during the experimental programme. The main objective of the study was to obtain ductile flexural behaviour from the shear deficient RC T-section beams. Debonding reduces the strengthening potential of the externally bonded CFRP thus obstructs structures to meet the expected requirement from strengthening materials. To block debonding, mechanical anchorages were used at the end regions of CFRP plates. Test results confirmed that all performance CFRP arrangements differ from type and wrapping scheme improved the strength and behaviour of the specimens in different level significantly. Nevertheless, specimens that were strengthened with t -jacketed bidirectional CFRP showed better strength and behaviour than the remaining specimens. To verify the reliability, test results were compared with results of ACI-440 design code and Concrete Society TR55. Notation a shear span d effective height of the cross-section f c compressive strength of concrete L length of the beam M cal calculated moment capacities of specimens M exp experimental moment capacities of specimens V exp: experimental shear forces of specimens V cal: calculated shear forces of specimens å CU maximum strain of concrete ö diameter of reinforcement Conversion factors 1 mm ¼ 0 . 039 in 1 mm 2 ¼ 0 . 00152 in 2 1 kN ¼ 0 . 2248 kips 1 MPa ¼ 145 lbf/in 2