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Precision Underwater Demolition Works on the Sava River – Removal of Piles at a Port Pontoon in Belgrade

During our operations on the Sava River in Belgrade, we also carried out a waterborne task that was independent of—but spatially closely related to—the demolition of the Old Sava Bridge. The objective of the project was the professional removal of an aged pile structure supporting an old port pontoon, which, if left in the riverbed, would have obstructed future development works and waterborne operations.

The demolition involved seven steel-sleeved, concrete-filled piles, each with a diameter of 600 mm. The elements were approximately 11 metres long and weighed around 11 tonnes each. Due to their size and location, removal was only possible from the water, with the involvement of industrial divers. A barge was positioned alongside the work area and equipped with a crawler-mounted lattice-boom crane, while lifting operations from the shoreline were supported by a mobile crane with a man basket.

The underwater cutting operations were carried out by industrial divers working from a diving stage. Using a cutting template on the riverbed, they performed circumferential cuts on the steel casings, ensuring precise and fully controlled demolition. Following the cutting process, the upper section of each pile was tensioned with a steel winch, the internal concrete core was broken, and the separated elements were lifted to the surface by crane. The works were executed as part of the project of Hídépítő Zrt., in close cooperation with the specialists of Búvár Kft.

After the extraction of the piles, an additional underwater demolition task requiring high precision followed. Inside the piles, residual concrete protruded approximately half a metre above the riverbed. This material had to be removed without damaging the surrounding slope and riverbed structure. A hydraulic breaker was mounted on an excavator positioned on the TS80 barge, while a diver working on the riverbed manually guided the position of the breaking tool. Throughout the operation, only the absolutely necessary amount of concrete was removed, with phased inspections and continuous repositioning.

The demolition works took one full day to complete. A multibeam survey carried out after completion clearly confirmed that the piles had been removed down to the designed level without causing damage, while fully preserving the integrity of the surrounding riverbed and slope.

Meticulous preparation, the coordinated use of surface and underwater equipment, and the continuous cooperation between divers and machine operators ensured that the intervention was completed in full compliance with both client expectations and technical requirements.