PSI - Issue 78

Lorenzo Ciccarelli et al. / Procedia Structural Integrity 78 (2026) 1428–1435

1431

Fig. 3. Fiber section on piles.

Table 1. Mechanical parameters of confined and unconfined reinforced concrete. Parameter Unit Unconfined Confined

K fc

[-]

1

1.089 12.15

[Mpa]

12.15 0.002

Kent and Park model

εc0 εc1 εcu

[%] [%] [%]

0.0022 0.0063 0.0073

0.0034 0.0035

Table 2. Mechanical parameters of steel. Parameter Unit

fy

[Mpa] [Mpa]

288

Menegotto and Pinto

E

206000 0.0034

b

[-]

Finally, given the critical role of degradation, particularly reinforcement bar corrosion, in seismic vulnerability, and its frequent omission in standard assessment procedures, relevant corrosion scenarios have been identified. Their effects on material properties have been modelled, as discussed in the following sections, in order to investigate their detrimental influence on structural performance. 3.2. Corrosion-induced reduction of mechanical parameters To evaluate the impact of degradation on the material parameters, various formulations were employed. For the reduction in concrete compressive strength due to corrosion phenomena, the formulation proposed by Vecchio and Collins (1986) was used: = ∗ = 1+ 1 2 2 (1) where is the compressive strength of the uncorroded concrete, ∗ is the compressive strength of the corroded concrete, is a constant equal to 0.1, is the corrosion penetration in the reinforcement bars, is the transverse width of the section, 2 is the strain corresponding to concrete yielding and n bars is the number of bars in the compressed zone. In (Di Sarno & Pugliese, 2020), an evaluation was proposed to reduce the mechanical capacity of concrete sections based on a weighted average of the strengths of three blocks formed by cover concrete (CC), non-effectively confined core (UCC), and effectively confined core (ECC). However, for the present case study, the resistance was assigned to each individual fibre accounting for its actual location within one of the aforementioned blocks.