PSI - Issue 64

Parinaz Panjehbashi Aghdam et al. / Procedia Structural Integrity 64 (2024) 65–73 Panjehbashi et al. (2024)/ Structural Integrity Procedia 00 (2019) 000 – 000

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2.2. Test procedure and instrumentation

The loading was applied by hydraulic jack in a displacement-controlled mode through a distributive beam to perform the four-point flexural test. The displacement of the steel beam and the slip between the steel beam and PCHC slabs was monitored by potentiometers, strain gauges, and a data acquisition system, as presented in Figure 4.

Fig. 4. Instrumentation of the full-scale flexural test.

2.3. Test results and load-deflection curves Figure 5 presents the load-mid-span deflection curves for the two full-scale specimens. These curves indicate three distinct stages: elastic, elastoplastic, and descending. During the elastic phase, the load-deflection curve exhibits linear behavior. Later, the lower flange of the steel beam yielded at approximately 80% of its ultimate capacity (P u ), leading to a rapid increase in mid-span deflection. Peak points were observed at 1638 kN and 1600 kN for the first (a) and second (b) specimens, respectively. This phase demonstrates a nonlinear relation with a degrading stiffness. Finally, the load and nonlinear deflection of the beam decreased suddenly, leading to residual deflection. The position of the potentiometers on the bottom flange of the steel beam is provided in Figure 6.

a

b

Fig. 5. Load (kN)-mid-span deflection (mm) curves of the (a) 254 mm and (b) 203 mm flexural specimens. eflection mm eflection mm