PSI - Issue 84

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

988

7000 6000 5000 4000 3000 2000 1000 0

0.00

Compressive strength limit

Deck failure

Force [ton]

(b)

(a)

0

0.5

1

1.5

2

2.5

Compressive stress [MPa]

Deflection [m]

-35.0

Fig. 9. Push-down analysis: capacity curve with compressive strength of concrete (a) and deck failure points (b).

5. Demolition scenarios 5.1. Method 1 - Uplift with Jack‑Up Steel Platform

In the final scenario, external post‑tensioning (PTE/PTE2) remained active, concrete strength was 54 MPa (per testing), and platform self‑weight included the ~32‑ton protection wall. As jacking proceeded, tower reactions stabilized around ~400 tons per tower. Uplift analysis monitored the gap closing between the concrete deck and the steel platform to ensure no accidental contact would occur. The deck–platform gap closed by ~170 mm at full lift (Figure 10).

60

55.5

(a)

50 40 30 20 10 0 -10

Steel Platform Concrete Deck

Closing of gap

(b)

Vertical disp. [cm]

Vertical disp. [cm]

0 100 200 300 400 500 600 700 800 900 1000 Increment [-] 43.0

Fig. 10. Uplift analysis: deck-platform gap closing during uplift (a) and relative vertical deflection of the steel platform (b).

The cantilever portion of the deck was found able to withstand the up-lift load introduced by the steel platform with safety factors within standards (Figure 11).

SF=1 (fy=2.35MPa)

SF=1.5 (fy=1.55MPa)

SF=2 (fy=1.15MPa)

Fig. 11. Uplift analysis: cantilever tensile stresses under different safety factors [MPa].