Hydrodemolition removes concrete from 120 m high bridge pylon in St Petersburg

The Project

ICA Construction of St Petersburg has used two Aquajet robotic hydrodemolition machines to clear concrete from the top of a 120 m high bridge pylon.

Benefits

• No need for a large gang of jackhammer operators working high up on the pylon
• No need to build any platforms or scaffolding
• Clean cutting of the concrete
• Saving time and effort by removing vertical rebar

Details of the Hydrodemolition

Two Aqua Cutters from Aquajet Systems AB were used to remove surplus concrete from around the inner steel structure of a pylon for the Petrovsky Fairway Bridge, part of the Western High-Speed Diameter (WHSD) at St Petersburg in Russia.

Project Overview

The Petrovsky Fairway Bridge is a 560 m cable-stayed structure across the River Neva to link two islands, reducing transportation time from more than one hour on the existing congested roads to between 10 and 15 minutes. The bridge features two needle-shaped towers each 120 m high, with a central span of 240 m and a bridge under-clearance of 25 m.

Hydrodemolition Equipment Used

Aqua Spine from Aquajet was used for this project. It is described as the most effective and flexible equipment for this type of job, allowing the system to be assembled in the required size using the multimodular Aqua Spine. The height of the area to be removed was 10m, so the system was assembled in the same length and set up on the ground to reduce the setup time.

Water Source and Filtration

The water source was the Finnish Gulf, and three-level filtration was used to prepare water for the plunger pump. The used water was fed back into the sea, ensuring that the water pumped back into the Gulf was almost entirely clean.

Conclusion

Max Petrov, Development Director for DUS, stated that the advantages to ICA included clean cutting of the concrete, saving time and effort by removing vertical rebar, and avoiding the need for a large gang of jackhammer operators or platforms/scaffolding. This project is part of a larger US$1.6 billion contract for the construction of an 11.57 km section of the highway under a four-year construction programme that includes three major high-level bridges, low-level viaducts, and smaller overbridges. The market for Aquajet robots is expected to grow strongly within the next two to three years.