# Deep Embedment (DE) FRP Shear Strengthening of Concrete Bridge Slabs under Loads Close to Supports
## 7 Conclusions  
This paper presents the results of an experimental investigation involving eight tests on concrete slabs strengthened with deep embedment FRP bars subjected to loads close to the supports. A NLFEA model was proposed to simulate the structural behaviour of the test slabs. The accuracy of the proposed numerical model was validated by using the experimental results in this study. Additionally, a design method for prediction of loading-carrying capacity, including flexural and shear capacity, was adopted. The ultimate capacity predicted by this method showed good agreement with the test results. The main findings of this research are shown as follows:  
1. Due to the loading location close to the support, shear failure occurred in the unstrengthened test slabs. The failure mode is brittle and sudden. The deep embedment shear strengthening technique can be used to avoid the occurrence of shear failure of concrete slabs subjected to load close to supports. It was found that the failure mode of concrete slabs varied from brittle shear failure to ductile flexural failure. This was attributed to the broken continuity of shear cracking development by the deep embedment strengthening method. 2. It was found that the material type of embedment strengthening materials does not influence the behaviour of strengthened test slabs. Interestingly, increasing the diameter of embedded FRP bars results in larger ultimate capacity and higher ductility. 3. Due to the small flexural stiffness of test slabs, the ultimate capacity was enhanced by around 10% by using the deep embedment strengthening method. However, the ductility of the test slabs was improved significantly. The maximum vertical deflection of concrete slabs at failure was increased by more than 100%, and the ductility was increased by more than 200%. 4. A NLFEA model for the concrete slabs shear strengthened with deep embedment FRP bars was developed and validated using the test results in this study. This NLFEA model shows a good capability of simulating the structural behaviour of the test slabs accurately, including the \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Test Specim** & **Pt (kN)** & **Pcs (kN)** & **PIFRs (kN)** & **Ps (kN)** & **Pb (kN)** & **Pb * (kN)** & **Pb */Pt** \\ \hline S-Con & 130 & 120.4 & — & 120.4 & 137.41 & 120.4 & 0.93 \\ S-B-2-9 & 144 & 120.4 & 15.87 & 136.27 & 137.41 & 136.27 & 0.95 \\ S-G-2-9 & 138 & 120.4 & 14.65 & 135.05 & 137.41 & 135.05 & 0.98 \\ S-C-2-9 & 138 & 120.4 & 35.4 & 155.8 & 137.41 & 137.41 & 1.00 \\ S-C-1-9 & 142 & 120.4 & 38.62 & 159.02 & 137.41 & 137.41 & 0.97 \\ S-C-1-13 & 148 & 120.4 & 62.94 & 183.34 & 137.41 & 137.41 & 0.93 \\  & & & & & & Average = & 0.96 \\  & & & & & & Standard deviation = & 0.03 \\  & & & & & Coefficient of variation = & 0.03 \\ \hline \hline \end{tabular}  
* Pp = Predicted ultimate capacity in the proposed method.  
\end{table} 
Table 6: Experimental and theoretical prediction loading-carrying capacity. ultimate capacity, strain response, and cracking patterns. This numerical model can be used by engineers and researchers for the structural analysis and assessment of the structural performance of concrete slabs strengthened with deep embedment FRP bars. * By using the model by [PERSON] et al. [20] to predict the shear resistance contributed by deep embedment FRP bars, a two-way design approach was proposed in this study, in which flexural and shear capacity were predicted separately. With the comparison of the test results, it was found that this theoretical model can predict the loading-carrying capacity and failure mode of the strengthened concrete slabs accurately. [PERSON] and [PERSON] conceived and designed the experiments; [PERSON] performed the experiments; [PERSON] and [PERSON] analyzed the data; [PERSON] and [PERSON] wrote the paper. The authors wish to express their sincere appreciation of the Guangdong Science and Technology Planning (No. 2016A010103045), the Innovation Research Project by Department of Education of Guangdong Province (No.