PSI - Issue 64

Tahreer M. Fayyad et al. / Procedia Structural Integrity 64 (2024) 708–715 Tahreer M. Fayyad / Structural Integrity Procedia 00 (2019) 000–000

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Cracks in reinforced concrete structures follow a tortuous path. To pinpoint the crack profile, the crack opening was measured from points at a uniform vertical distance from the beam's bottom. For assessing the crack opening at various points along the crack, extensometers positioned on either side of the crack. The length of the extensometers was set to be 15 mm and the vertical distances between them was 10 mm (Fig. 5(b)). The horizontal position of the extensometers was selected in reference to the last frame (Fig. 5(c)) to guarantee that the complete opening of the crack is counted. Due to the complication of process fracture zone ahead of the crack tip, the length of the crack was considered at the vertical distance when the change in the extensometer measurements is less than 0.2mm. This enabled a full construction of the crack geometry, crack propagation and crack opening, with time.

(a) (C) Fig. 5. (a) Displacement field Beam C45_0.3_1; (b) Extensometers positions; (c) Extensometers positions in reference to the final crack (b)

Fig. 6. Crack opening over the vertical extensometers C45_0.3_1 The Integrated Fracture-Based Model (IFBM) is a model that predicts the responses of lightly reinforced concrete beams. This advanced model, offering a closed-form solution, effectively synthesizes various localized phenomena, thereby providing an understanding of initial crack formation, crack progression, and crack orientation changes. The model incorporates post-cracking tensile stresses in the concrete, the bond-slip behaviour between the reinforcement and concrete, and compression softening in the concrete compressive zone. The reader is referred to references (Fayyad & Lees, 2015)(Fayyad & Lees, 2017) for insight into the model basis, theory and formulation. Since the model can predict parameters such as the crack length development and crack mouth opening displacement in Mode I lightly