PSI - Issue 78

Dario De Domenico et al. / Procedia Structural Integrity 78 (2026) 65–72

69

system. Hence, the position of the inspection hole is representative of the position of the artificial damage that has been simulated in the prestressing system of the tested PC beams. The R01 series features inspection holes located at mid-span. In contrast, beams from the R03 series have inspection holes placed at one-quarter of the clear span, while those in the R04 series have them at one-third of the span. The R02 series differs in that it utilizes unbonded prestressing strands: across the full clear span, the strands were encased within plastic ducts to prevent bonding with the surrounding concrete. Anchorage to the concrete was achieved only at the two ends of each beam, over segments having length 50 cm. 2.3. Layout of sensors and loading configurations To comprehensively monitor the structural response of the specimens throughout the different stages of the experimental program, a carefully planned sensor network was implemented. This system captures acceleration, deflection, rotation, and crack propagation under varying load conditions.

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Fig. 3: Configurations of sensors in tested prestressed concrete beams

The sketch of the sensor s’ layout is shown in Fig. 3 and includes: a) Five wired MEMS sensors, functioning as 3D accelerometers (±2g full scale with adjustable sampling frequency) and 2D inclinometers (gravity-sensitive accelerometers with ±0.5g full scale). These sensors are mounted on steel brackets fixed to the lateral sides of the beam specimens. b) Four piezotronics PCB 1D accelerometers (model 393a03_PCB, sensitivity 1V/g, ±5g range), fastened to plates bonded on the same brackets as the MEMS sensors, for comparison of measurement data. c) Five laser sensors (model WSD15IIDIST), for measuring both relative and absolute distances, and rotations about two orthogonal axes. These are mounted on concrete blocks secured to the laboratory strong floor. d) Linear variable displacement transducers (LVDTs), including two Solartron Metrology V10005SBN3 units (±50 mm stroke), used as crack meters during loading phases; and one Monitran MTN/IEUSAL100-10 LVDT (±100 mm stroke), installed under the specimen to record mid-span deflection. Regarding the loading scenarios, a clear distinction is made between service loads and ultimate loads. During service load tests, the transverse IPE80 beam is included in the experimental setup. To avoid any damage to the beam under these conditions, the applied live load from the jack must be kept below the threshold that would cause