PSI - Issue 78

Rawand Alnsour et al. / Procedia Structural Integrity 78 (2026) 1261–1268

1264

(b)

(a)

Fig. 5. (a); (b ) Crack pattern of RC beam strengthened with NSM CFRP strips (Jedrzejko et al., 2023).

2.5 Hybrid techniques The hybrid approach to shear strengthening in RC combines several techniques, such as externally bonded FRP (EB FRP), mechanical fastening (MF), near-surface embedding (NSE), and fabric-reinforced cementitious matrix (FRCM), to overcome the limitations of individual methods. These integrated systems enhance shear strength, ductility, and bond performance. For instance, the EB/MF-FRP system reduces debonding by anchoring FRP strips with mechanical fasteners. Hybrid Composite Plates (HCPs), made of strain-hardening cementitious composite (SHCC) reinforced with CFRP, offer excellent strength and durability. Similarly, the NSEEB-FRCM technique applies both embedded and surface-bonded layers to enable thicker, more compatible reinforcement. Together, these hybrid systems provide a more efficient, durable, and resilient solution for RC beam strengthening. (Baghi et al., 2017; Ebead & Saeed, 2013). Fig. 6 (a) and (b) illustrate the hybrid NSE/EB technique for improving the shear capacity of RC beams using FRCM (Wakjira & Ebead, 2018).

(b)

(a)

Fig. 6. (a); (b ) Applying the hybrid NSE/EB technique (Wakjira & Ebead, 2018).

2.6 Mechanical anchorage system Mechanical anchorage systems are used to secure externally bonded reinforcement (EBR) materials, such as FRP, to RC structures, using fasteners like anchor bolts, instead of relying solely on adhesives. Common types include expansion anchors, threaded bolts, powder-actuated fasteners, and specialized FRP anchors (e.g., pin-and-fan types). These systems improve load transfer, ensure composite action, and are often faster to apply on-site due to minimal surface preparation and no curing time. They are especially effective in shear strengthening and retrofitting applications (Abuodeh et al., 2021; Mohamed et al., 2020). Fig. 7 (Bae & Belarbi, 2013) shows various strengthening configurations for the anchorage of EB CFRP sheets incorporating anchor bolts and strips to enhance the shear capacity of the RC beam.