# Neural Networks--Deflection Prediction of Continuous Beams with GFRP Reinforcement
## 2 Materials and Methods  
In this paper, we used the data obtained in an experimental research which was conducted on two-span continuous beams with GFRP reinforcement and loaded with concentrated forces in the midpoints of the spans. After data collection, their analysis was performed. The next step was to prepare the analyzed data for model formation. The last step was to define the final model for the prediction of deflections in continuous beams. The experimental research included 11 continuous beams with a total length of 394 cm. The beams were on two spans 185 cm long and with overhangs of 12 cm each (see Figure 1). The cross-sectional dimensions of the beams were 15 \(\times\) 25 cm. Details of all 11 experimental beams are given in Table 2.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline  & **Longitudinal** & **Longitudinal** & **Reinforcement** & **Cross-Section** \\
**Beam** & **Reinforcement** & **Reinforcement** & ** \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Beam**} & **Longitudinal** & **Longitudinal** & **Reinforcement** & **Cross-Section** \\  & **Support—Upper Zone** & **Midspan—Lower Zone** & & \\ \hline B3 & 2\(\Phi\)10 + 1\(\Phi\)12 & 2\(\Phi\)14 + 1\(\Phi\)12 & GFRP & \\  & & polyester—wrapped & \\ B4 & 3\(\Phi\)12 & 3\(\Phi\)10 & GFRP & \\  & & polyester—wrapped & \\ B5 & 2\(\Phi\)9 + 1\(\Phi\)12 & 2\(\Phi\)12 + 1\(\Phi\)9 & GFRP & \\  & & polyester—wrapped & \\ B6 & 2\(\Phi\)9 + 1\(\Phi\)10 & 2\(\Phi\)12 + 1\(\Phi\)10 & GFRP & \\  & & polyester—wrapped & \\ B7 & 3\(\Phi\)7 & 2\(\Phi\)6 + 1\(\Phi\)7 & GFRP & \\  & & polyester—wrapped & \\ B8 & 2\(\Phi\)6 + 1\(\Phi\)7 & 2\(\Phi\)97 + 1\(\Phi\)6 & GFRP & \\  & & polyester—wrapped & \\ B9 & 4\(\Phi\)12 & 2\(\Phi\)10 + 2\(\Phi\)9 & GFRP epoxy—ribbed & \\  & & (deformed) & \\ B10 & 3\(\Phi\)10 + 1\(\Phi\)12 & 2\(\Phi\)12 + 2\(\Phi\)9 & GFRP epoxy—ribbed & \\  & & (deformed) & \\ B11 & 3\(\Phi\)9 & 3\(\Phi\)12 + 1\(\Phi\)10 & GFRP epoxy—ribbed & \\  & & (deformed) & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Cont. The beams were loaded with concentrated loads in the midpoints of both spans up to failure. Nine beams were reinforced with GFRP longitudinal and transverse reinforcement to experience concrete compression failure, while two beams were designed to experience FRP reinforcement failure. The main parameters which vary are the ratio of quantities of longitudinal reinforcement in the middle of the span and above the support--in other words, the designed redistribution of moments--the percentage of reinforcement with longitudinal reinforcement and the type of GFRP reinforcement. Two types of GFRP bars were used for the longitudinal reinforcement: GFRP reinforcement with 70% longitudinal fiberglass (E-glass) in total volume, impregnated in an unsaturated polyester matrix, and GFRP reinforcement with 75% longitudinal fiberglass (E-glass), impregnated in an epoxy matrix. GFRP reinforcement with polyester was wrapped in fiberglass, while GFRP reinforcement with epoxy was ribbed (Figure 2), in order to improve the adhesion conditions between the concrete and reinforcement. GFRP stirrups with polyester were used in all the beams. Two designed concrete classes were used in the experiment of 28 MPa and 40 MPa, which represent compressive strength concrete cylinders with the dimensions 15/30 cm. Continuous beams were placed on three supports over steel bearings. The end supports were designed to be movable in the horizontal direction. The middle support was designed so that horizontal movement is prevented. The load was applied with the help of hydraulic presses placed in the middle of both spans (Figure 3). Deflections along the spans of continuous beams were measured with electric LVDT transducers, the accuracy of which was 1/100 mm (in the middle of the span) and 1/50 mm (in quarters of the span). They were placed on the lower edge of beams in quarters of the span, i.e., there were three LVDT transducers in each span. This was a load-controlled experiment.