Numerical Insights into Optimizing Anchor Embedment for CFRP-Strengthened Concrete Beams

Reinforced concrete (RC) beams can be effectively strengthened using carbon fiber reinforced polymer (CFRP) sheets in
conjunction with fiber anchors. Among available anchorage systems, fiber anchors have shown high efficiency in securing CFRP sheets.
The embedment depth of fibre anchors is a critical parameter influencing the effectiveness of CFRP strengthening in reinforced concrete
T-beams. However, its optimal range for ensuring full tensile mobilisation of CFRP remains insufficiently defined. To address this gap,
this present study investigates the minimum embedded depth required to achieve maximum load capacity, while ensuring a desirable
shear-out failure mode of the CFRP anchors. Advanced finite element (FE) modeling and analyses were conducted for various depths
ranging from 30 mm to 100 mm using Abaqus FEA software on eight, full-scale T-shaped RC beams with identical geometry and material
properties. The only variable among the beams was the embedded depth of the fiber anchors. The models were rigorously validated
against experimental data, achieving excellent agreement across load-deflection behaviour, load-strain response in concrete, steel, and
CFRP sheets, and observed failure modes. Results indicate that shallow embedment led to premature pull-out failures and limited CFRP
utilisation. While an embedded depth of 100 mm provides optimal performance, enabling full utilization of the CFRP anchors without
premature pull-out failure. Moreover, the numerical findings align closely with previous experimental results conducted under the same
beam configuration, supporting the reliability of the proposed model. These insights provide valuable guidance for the design and
application of anchor systems in CFRP-strengthened RC beams.