PSI - Issue 84

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

1295

initiated and localized in critical sections (the dapped ends). In addition, they exhibit common failure mechanisms including diagonal tension leading shear collapse; flexural yielding at midspan and; local crushing of concrete in the nib area. Being a critical subset of reinforced concrete bridges in Italy, half joints therefore requires tailored assessment and intervention strategies considering the several typologies of half joints that exist (Granata et al., 2022). Several retrofitting options are available for improving the effective performance of deteriorated reinforced concrete structures. Particularly for Geber-girder, the focus is usually to address possible shear failure at the dapped end. Typical available solutions include repairing the deteriorated dapped end; changing the static scheme of the beam by connecting the two dapped end to eliminate the hinges; steel jacketing; composite materials retrofits and; external post tensioning (Picciano et al., 2024). Finite element modelling has been widely utilized in the assessment of the structural behaviour of reinforced concrete half-joints. Several studies have implemented this numerical modelling solution to effectively analyze half joints to gain insights about the structural capacities, damage properties, failure modes, deterioration effects as well as estimate retrofitting outcomes (Domenico et al., 2025; Granata et al., 2022; Quadri & Fujiyama, 2021). Particularly, numerical models have been implemented for half joint retrofits using steel jacketing (Bertagnoli et al., 2023; Di Benedetto et al., 2025) and post tensioning (Santarsiero & Picciano, 2023) which are both traditional approaches. However, there is limited study on the implementation of such numerical models for non-traditional solutions like the use of composites. This study is therefore focused on developing a finite element model for non-traditional retrofit strategies for half joints with the aim of understanding the effectiveness of such approach. In this present study, a 3D finite element model was developed following available experimental result on fiber reinforced cementitious matrix (FRCM) strengthening of half joints by (Flores Ferreira et al., 2023), while further simulating additional deterioration due to reinforcement corrosion using an improved corrosion modelling strategy. The numerical model was developed using the STKO software for OpenSees (McKenna, 2011; Petracca et al., 2017). The model was calibrated and the results from the experimental campaign (the original and retrofitted specimens) were used to validate the model which was then used for further analysis. To simulate deterioration of the internal reinforcement, an advanced corrosion modelling approach was implemented for corrosion levels of 10 - 50% cross sectional mass loss. This advanced corrosion modelling was implemented to explicitly account for the coupled effects of cross-section loss, constitutive model variation and bond slip degradation. Thereafter the numerical modelling for the FRCM retrofits was developed and applied to the deteriorated beams to characterize the effect of the retrofit. 2. Reference Experimentation The reference experiment adopted for this study originated form the extensive campaign carried out by (Flores Ferreira et al., 2023). This study involved the analysis of sets of scaled reinforced concrete dapped end beams. The four identical beams had depths of 650 mm for the full section and 325 mm for dapped ends. The authors adopted the implementation of diagonal and horizontal reinforcement layers in the D-region of the beam. The full details of the beam geometry and the various reinforcement layers and sizes have been presented in Fig. 1 and the material properties of the concrete and reinforcements are presented in Table 1 and Table 2

Fig. 1. Geometry and reinforcement detail of reference study *All dimensions are in (mm)