# Structural Behavior of Large-Scale I-Beams with Combined Textile and CFRP Reinforcement
## 2 Experimental Investigation: Materials and Methods
### Test Setup and Instrumentation  
To test the beams with a uniformly distributed load, an inverse setup was employed (Figure 3) [60]. Ten equally spaced hydraulic jacks connected to one hydraulic circuit applied the load to the lower chord  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Characteristic** & **Unit** & **Own Tests** & **Manufacturer [49]** \\ \hline Modulus of elasticity & [MPa] & 165,515 * & 151,000 * \\ Mean ultimate stress & [MPa] & 1828 * (\(n=5\) tests) & 1650 * \\ Mean ultimate strain & [\%o] & 11.04 & 10.9 \\ core diameter & [mm] & 8.9 & 8.5 \\ nominal diameter ([50], Annex A) & [mm\({}^{2}\)] & 9.5 & - \\ outer diameter & [mm\({}^{2}\)/m] & 10.0 & 10.0 \\ Mean bond force per embedded length, & & & \\ values from MFPA Leipzig GmbH [51] & [kN/mm] & 0.976 (\(n=12\) tests) * & - \\ \hline \hline \end{tabular}  
* Reference cross-section area 61.5 mm\({}^{2}\). + Reference cross-section area not given by manufacturer, supposedly 56.7 mm\({}^{2}\).
* Determined on cubic specimen (age 28 d) according to RILEM-Pull-out [52], embedded length (50, 75 or 100 mm) in the center of the specimen, concrete C3-B2-HF-145-3 with \(f_{\rm cm,pris}=111.3\) MPa and \(f_{\rm cm,fl}=10.3\) MPa.  
\end{table}
Table 2: Reinforcement characteristics for carbon bars.  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Substance** & **Content** \\ \hline  & **kg/m\({}^{3}\)** \\ \hline Cemertitious binder compound CEM II/[PERSON] & 663 \\ Fine quartz sand BCS 413 0.06/0.2 mm & 240 \\ Quartz sand Hahnenberg 0–0.2 mm & 506 \\ Lengefelder Marmor Saxogan (crushed marble) 2.0–4.0 mm & 832 \\ Superplasticizer (polycarboxylatether-basis) MC-VP-16-0205-02 & 14 \\ Water & 145 \\ \hline \hline \end{tabular}  
\end{table}
Table 3: Mix design of concrete C3-B2-HF-2-155-5.  
of the beams. A package of steel (\(300\times 300\times 30\) mm) and plywood (\(t=21\) mm) plates reduced local stress concentrations. Spherical bearings centered the vertical load while curvature of the beams increased during the test. Initial geometrical non-linear finite-element calculations employing a horizontal line-load equivalent to an imperfection of 30 mm in mid-span predicted deformation-induced lateral failure of the beams' compression chord prior to bending failure. Thus, lateral supports in mid-span with polytetrafluorethylene (PTFE) facings were added. All specimens were tested under quasi-static conditions with a load rate of 10 kN/min. At predefined intervals, the test was halted to mark new cracks and document the crack pattern. After reaching a midspan deflection of 28 mm, all beams were completely unloaded and reloaded to identify plastic deformation and remaining crack-openings.  
Vertical displacement (DU1-DU6) was measured at supports, in in mid-span and at two locations in between (Figure 3). Three horizontal linear variable displacement transducers (LVDT) Bi1-Bi3 in the tension zone and nine (eleven for FT02) concrete strain gauges in the compression chord tracked deformations from the exterior. For internal measurement, strain gauges were applied to the main carbon bars. Therefore, one section of a rib was carefully sanded off without damaging the core diameter of the bars and the gauges were glued on the CFRP rebars. The feasibility of this measurement was evaluated in previous uniaxial tensile tests, where strain measurements with conventional LVDTs and strain gauges yielded similar results. For FT01 and FT02, six gauges (D1S-D6S) were fixed at the second and fourth bar of the outermost reinforcement layer (Figures 3 and 4). For FT03, a total of eight gauges were used, four outside of the splice, and four in the first and last third of the splice length.