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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the damage mechanism. The findings from this dual-technique approach can then inform the refinement of model for flexural cracks, enhancing its accuracy with real-world data derived from the combining the use of DIC and dynamic

frequency measurements. 2. Experimental testing 2.1. Test specimens

Two series of a total eight reinforced concrete beams each with beam size of 130 mm x 130 mm x 840 mm were cast and tested in three-point bending with the distance between supports was 800 mm. The flexural crack propagation was tracked using DIC. The reinforced concrete beams did not have shear links (Fig. 1). The first series included four beams with longitudinal reinforcement ratios of 0.3% and 0.5% cast from a mix with a design concrete cube compressive strength of 45 MPa and 60 MPa. The second series included four reinforced concrete beams that were prepared and cast typically as the beams in the first series. All the test beams had a concrete cover of 30 mm. The 1T6 steel reinforcement used is a smooth bar, while the 1T8 reinforcement is a ribbed bar. The reinforcement ratio, dimensions and length were selected so that the beams were lightly reinforced and would fail in a ductile flexural manner rather than sudden shear failure. The details of the test beams are summarised in Table 1.

Fig. 1. Test specimen layout, preparation and casting

Table 1. Details of test series Beam dimensions (mm) × (mm) × (mm)

compressive strength (MPa)

Reinforcement (ratio)

Notation

1T6 (0.3%) 1T8 (0.5%) 1T6 (0.3%) 1T8 (0.5%) 1T6 (0.3%) 1T8 (0.5%) 1T6 (0.3%) 1T8 (0.5%)

C45_0.3_1 C45_0.5_1 C45_0.3_1 C60_0.5_1 C45_0.3_2 C60_0.5_2 C45_0.3_2 C60_0.5_2

45

Series 1

130 × 130 × 840

60

45

Series 2

60

2.2. DIC experimental setup In an analysis employing Digital Image Correlation (DIC), a base image encompassing the targeted zone is segmented into small speckles. These speckles are monitored and tracked through sequential images. This process enables the quantification of the deformation across subsequent images. For the precise monitoring of these speckles, it is vital that each speckle possesses distinguishable features that set it apart from its counterparts. To achieve a