PSI - Issue 64

Nikhil Holsamudrkar et al. / Procedia Structural Integrity 64 (2024) 815–821 Holsamudrkar Nikhil et al./ Structural Integrity Procedia 00 (2019) 000 – 000

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3.1. Specimen S2-AN This specimen has been reinforced using an S2 on-site strategy with anchorage, indicating an ultimate load capacity of 160.4 kN with fabric rupture failure. Meanwhile, the control RC beam fails at an ultimate load of 125.1 kN. The load-displacement curve delineates three distinct phases, as depicted in Fig 2. Phase I denotes a linear elastic response with the steel remaining unyielded. Phase II signifies the yielding stage, wherein FRCM multi-cracking occurs. Phase III marks the post-FRCM failure stage, where the residual ductility of the steel contributes. These phases are discernible through changes in both the slope of AE cumulative hits and the CSS curve. The event rate suddenly increases in the second phase, indicating increased FRCM damage activity. Despite this, the average frequency essentially maintains its proximity to 125kHz, indicating mortar matrix/ concrete cracking. Following Phase II, there's a notable spike in the RA value due to sensor detachment from the FRCM side following failure. Historical index exhibit peaks correlating with significant events during the test. The RA-AF plot illustrates damage primarily dominated by tensile mode, accounting for 91.80% of the hits. 3.2. Specimen S3-AN This specimen has been reinforced using an S3 on-site strategy with anchorage, resulting in an ultimate load capacity of 181.5 kN before the failure of the FRCM system. The significant increase in load capacity 0f about 44% is due to the combined effect of on-site impregnation process (Holsamudrkar et al., 2024) and anchorage. Fig 3 provides a comprehensive overview of all the results.

Fig. 3. Variation of (a) Cumulative AE hits for different channels wrt time, (b) Average frequency, RA value, Event rate wrt time, (c) Historic index, Cumulative signal strength wrt time, and (d) AF-RA scatter plot for the specimen S3-AN