PSI - Issue 84

Ahmed Amir Khalil et al. / Procedia Structural Integrity 84 (2026) 1031–1038

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3. Numerical models 3.1. Boiler unit

3D model of the boiler unit is implemented in the ELS Extreme Loading for Structures software. An overview of the model is reported in Figure 1. The Applied element method technique allows a 3D high fidelity representation of crucial structural details without a disproportionate computational effort, Grunwald C. et al. (2018). For example, a detailed modelling of the top steel frame supporting the heavy equipment (boiler and air heater) is implemented, Figure 3. Even the nonstandard steel columns strengthened with steel plates at axis G & J are explicitly reported in the model.

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b

5.0m

Fig. 3. (a) isometric view of the top steel frame; (b) detail of the girders supporting the boiler. The demolition scenario provides the weakening of the structure through the removal of beams and bracings at the lower level. The columns along axes E & F are weakened with flat cut while the columns along axis G are provided with hinge cut. To facilitate the collapse of the structure, some columns at level 4,5 and 7 present double V-cut with 10 cm steel tag left at the flanges. The removal of the structural elements and the cut in the columns are explicitly implemented in the model through different stages, to analyze the updated stress configuration and evaluate the safety of the different stages of cutting. From axes Mb to H shaped charges are installed on the columns at ground level to blast the structural elements with 0.25 sec. detonation delay, see Figure 4.

Girders and bracings to remove: Preparation stage Girders and bracings to remove: Stage 2

Girders and bracings to remove: Stage 3 Girders and bracings to keep

Hinge cut detail: 1: 25% of section length, V cut 45 deg 2: 25% flat cut

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Fig.4. Ground floor of the boiler structure with the girders and bracings to remove and indication of columns to cut and explode.