PSI - Issue 84

Emeka John Ude et al. / Procedia Structural Integrity 84 (2026) 1294–1301

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4.3. Corrosion and Strengthening

For the simulation of FRCM strengthening due to corrosion, this study adopted one of the improved FRCM strengthening option (RTF-IMP-0). From the resulting load curves for corroded specimen (Fig. 9a), it is observed that there is a consistent pattern of initial peak load (between 164 kN and 194 kN) at the early stage followed by a sharp drop and seemingly horizontal softening plateau. This large difference in peak capacity and failure pattern between the beam with reinforcement corrosion and the original beam can be attributed to partial exploitation of the reinforcement capacity following the decay of the concrete-beam bond strength as explicitly defined in the model. In the case of the retrofitting of the half joints with corroded reinforcement, it can be observed that there is a change in the failure mode which appears to be more ductile across all corrosion levels (Fig. 9b). For corrosion levels 10 - 40%, they follow similar patterns with early initial cracking in form of an initial peak between 1 mm and 2.5 mm displacement, followed by a second peak (much higher than the first peak) between 15 mm and 10 mm displacements and a weak softening tail. For corrosion level 50% however, an initial peak with a sharp drop is observed followed by a second peak lower than the first. Overall, a significant improvement in the beam capacities - up 50.1% improvement due to the FRCM strengthening is observed with a progressive reduction in the retrofit effect as corrosion level increases. These increase in capacities and change in failure modes can be attributed to load redistribution in the between the internal reinforcement and external FRCM. Table 5 presents the summary of the improvement from FRCM retrofit.

(a)

(b)

Fig. 9. Load curve: Strengthening of half joint with corroded reinforcement

Table 5. Strengthening effect of FRCM for half joint with corroded reinforcement Corrosion level As-built (kN) Retrofitted (kN) Improvement (%) 10% 164 247 50.61 20% 164 230 40.24 30% 164 220 34.15 40% 166 208 25.30 50% 194 198 2.06

5. Conclusion Several studies have developed finite element models to investigate retrofit of half joints using traditional retrofit solutions. This current study has, however, focused on the use of finite element modelling approach to investigate FRCM retrofit of half-joint while implementing an advanced modelling of corrosion that combined the couple effects of cross-sectional loss, ductility loss and bond slip effects. The results from the validation of the case study experiment proves the possibility of implementing finite element model for analysing FRCM retrofits of half joint half joints. Particularly, the modelling strategy of the FRCM presents the possibility of modelling FRCM fiber in different directions while providing the option to easily alter the fiber spacing and number of fiber layers. Through the FE