PSI - Issue 44

Paolino Cassese et al. / Procedia Structural Integrity 44 (2023) 774–781 P. Cassese et al. / Structural Integrity Procedia 00 (2022) 000 – 000

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3.1 Panels O The experimental response of the specimens O1 and O2 is shown in Fig. 3 (a, b) and Fig. 4 (a, b) in terms of hysteretic curves and observed damage patterns at the end of the tests, respectively. Panel O1 exhibited some cracking lines during the set I of the loading protocol (IDR 0.10%), therefore the cracking force was assumed as the maximum force experienced by the element during this set. SG steel strain monitoring indicated that one of the longitudinal bars exceeded the yielding threshold, during the first cycle of set II (IDR 0.20%). Therefore, an advance of the damage evolution was evidenced in the outer layers or wythes. During set III, the lateral load supported by the panel continued to increase, and some additional cracks were observed in the panel close to the upper side of opening area. It is worthy to mention that panel O1 reached its maximum load during set IV with a force of 225.8 kN in pull direction and 249.2 kN for push direction, associated to an IDR value equal to 0.60%. Nevertheless, an important damage to the concrete matrix occurred in set V, beyond which the lateral resistance of the panel started to decrease. During set VI, the mechanical failure of the panel occurred, this latter assumed as associated to a lateral force reduction equal to 20% with respect to the peak value, for an IDR value equal to 1.02%. From set VI onwards, the presence of cracks was exacerbated. During sets VII, VIII and IX, the specimen experienced a stabilization of its lateral resistance corresponding to the 38% of the peak force.

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Fig. 3. Experimental Outcomes of cRCSPs: response of panels O1 (a) and O2.

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Fig. 4. Observed final damage patterns for specimens O1 (a) and O2 (b).