PSI - Issue 64

Mohamed Elkafrawy et al. / Procedia Structural Integrity 64 (2024) 436–444 Author name / Structural Integrity Procedia 00 (2024) 000–000

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(c) Fig. 5. Effect of pre-stressing level on the cracking pattern of beams a) B-150 b) B-150-2T25-0% c) B-150-2T25-50%. Openings decrease the beam’s load-carrying capacity. Fe-SMA bars are added around the openings to increase the ultimate load carried by the beams that have web openings. As seen in Fig. 6, this increased the ductility and ultimate load carried by the beam to more than that of the original control beam. In contrast, the ultimate load carried by the control beam is around 435 kN. When the beams have openings yet no reinforcements, the ultimate load carried by the beam with 100 mm, 150 mm, and 200 mm openings are 365 kN, 310 kN, and 238 kN, respectively. Adding reinforcement, whether pre-stressed or not, increased the beam’s ultimate load-carrying capacity. It can be seen that pre-stressing the Fe-SMA bars does not have a significant effect on the ultimate load carried by the beams. In contrast, the ultimate load carried by beams that are not pre-stressed and those that are pre-stressed to around 50% for 100 mm, 150 mm, and 200 mm openings were similar at around 502 kN, 501 kN, and 501 kN, respectively.

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(c) Fig. 6. Effect of pre-stressing level on the load-deflection response of beams: (a) B-100 (b) B-150 (c) B-200.

3.3 Effect on Ductility The ductility of each beam is calculated as the ratio of displacement at peak load to that at yield found from the load-deflection charts. As seen in Fig. 7, the control beam has a ductility index of 3.29, which decreases when the beam has an opening. This occurs because openings in a structure interrupt the regular distribution of stresses. This disruption leads to the concentration and buildup of stress, resulting in premature cracking around the opening. As a result, the beam experiences minimal deformation before failure (Ahmed et al. , 2012). The larger the opening size, the smaller the beam’s ductility. The results confirm this, whereas the beam with a 100 mm opening has a 2.88 ductility