PSI - Issue 84

A.A. Khalil et al. / Procedia Structural Integrity 84 (2026) 983–990

987

Fig. 6. Compression‑only interfaces at cold joints between precast and cast‑in‑place components: deck overview (a) and interface deta il (b).

4. Preliminary Analysis and Model Validation The numerical model was calibrated in terms of mesh-dependent effects by verifying midspan deflections, moment envelopes, and reaction distributions against hand calculations and independent FE estimates, confirming composite action between girders, slab, and diaphragms, and correct representation of prestress forces. Construction‑stage simulations reproduced tendon stressing, long‑term losses, and application of superimposed dead loads (Figure 7). The staged approach revealed nonlinear behavior as prestress was applied and losses introduced. Across three prestressing phases, the deck stabilized with final midspan deflections on the order of ~20 mm, consistent with construction reports.

0.08 0.06 0.04 0.02 0 -0.02 -0.04

+0.1

Construction stages stage

Stage 1

Stage 2

Stage 3

Deflection [m]

Single stage

0 25 50 75 100 125 150 175

Stage 4

Stage 5

Stage 6 -0.5

Increment [-]

Stages [-]

Fig. 7. Construction stage analysis: comparison of mid-span vertical deflection between single and multi-stage simulation [m].

A critical aspect of the analysis was the effect of tendon degradation, which is a common issue in aging prestressed concrete bridges. The model incorporated varying degrees of tendon strand losses based on inspection data. The analyses demonstrated that deck failure would occur when area-reduction was applied to 14 tendons out of 24 (Figure 8).

(b)

(a)

Fig. 8. Degradation analysis: deck’s collapse mechanism (a) and relative crack distribution (b).

The order of magnitude of the deck capacity was assessed through a push‑down analysis. The capacity of the deck was found to be almost four times its own weight (Figure 9).