## 3 Experimental Investigations  
To evaluate and validate the SCPT and to deeply analyze the shear failure behavior, an extensive experimental program with systematically varying boundary conditions (e.g., change in the flexural reinforcement ratio or maximum aggregate size) has been started at the Institute of Structural Concrete at RWTH Aachen University. The initial experimental results of a beam shear test and a first comparison with the SCPT are presented in this publication, while a more comprehensive evaluation of the entire test campaign will be published in the future. The investigated beam specimen B1 had a total length of \(L=4700\) mm and a rectangular cross-section of \(b\times h=320\times 350\) mm. To allow for two shear subtests B1-1 and B1-2 on beam B1, the test setup consisted of a simply supported beam with a cantilever so that the unloaded cantilever from the first shear subtest was used as the undamaged section for a second shear subtest (Figure 2). Due to this test set-up, the middle section of the beam could be used twice to save resources (e.g., concrete and reinforcing steel as well as formwork). In addition to these economic advantages, the concept of conducting subtests allows for ensuring that identical concrete and reinforcing steel material parameters are used in two shear tests. Accordingly, each shear test was performed as a three-point bending test with a total span of \(L=2800\) mm. The load \(F\) was applied with a distance \(a=1300\) mm from the left support so that the shear failure was expected to occur at this end of the beam. To prevent an unintended shear failure in the other end of the shear span, stirrups as shear reinforcement were applied in the middle section of the beam. The shear slenderness ratio was \(a/d=4.33\) and the bending slenderness was \(L/h=8\). The flexural reinforcement consisted of five bars with \(\mathcal{O}=16\) mm resulting in \(\rho_{1}=1.05\%\). The yield strain was \(\epsilon_{8}=2.89\%\), with a Young's modulus of \(E_{8}=199\) GPa providing a yield strength of \(f_{y}=575\) MPa. In the compression zone, two bars with \(\mathcal{O}=10\) mm were used for practical and detailing reasons. The nominal concrete cover of the longitudinal bars was \(\epsilon_{\mathrm{nom}}=40\) mm, resulting in a nominal effective depth \(d=302\) mm. A normal-strength concrete with a maximum aggregate size \(d_{\text{g}}=16\) mm was used. At the day of testing, the properties of the hardened concrete were identified in the material tests summarized in Table 1. The concrete compressive strength was determined on 150-mm cubes (\(f_{\text{cm,cube}}\)) and on concrete cylinders with \(d/h=150/300\) mm (\(f_{\text{cm,cyt}}\)), according to reference [39]. The splitting tensile strength (\(f_{\text{ct,sp}}\)) was tested on shortened cylinders (\(d/h=150/150\) mm). The mean modulus of elasticity (\(E_{\text{cm}}\)) was also tested on cylinders (\(d/h=150/300\)) with method \"B\", according to reference [40]. The test setup of the simply supported beam with a cantilever is shown in Figure 3. The load was applied using a 630-kN hydraulic jack. To reduce the local stress concentration, a steel plate (\(100\times 320\times 10\) mm) was used beneath the load application and at the supports. Additionally, a roller was placed under one support to allow for a free horizontal movement. Both supports were able to allow for rotations. The specimen was tested under quasi-static conditions with a load rate of 5 kN/min until failure. For up to 60-70% of the expected maximum shear capacity, the load was introduced load-controlled. After that, the load was applied deformation-controlled until a significant load drop indicated a clear failure. At predefined load steps-usually 12.5% \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Test No.** & **Age (d)** & \(f_{\text{cm,cube}}\) (MPa) & \(f_{\text{cm,cyt}}\) (MPa) & \(f_{\text{ct,sp}}\) (MPa) & \(E_{\text{cm}}\) (MPa) \\ \hline B1-1 \& B1-2 & 41 & 44.5 & 36.9 & 2.93 & 26,800 \\ \hline \hline \end{tabular}
\end{table}