ULMA Construction&UNI-SPAN alliance succeeds again in Australia

Project contractor Transcity sought an innovative solution for tunnel cantilever and ventilation duct installation. UNI-SPAN, the official distributor for ULMA Construction in Australia was awarded planning, supply and construction contracts for both tunnels in this project from the outset.

This is the first time an Australian tunnel has included pre-stressed slabs of prefabricated concrete resting on just an in-situ poured cantilever. The assembly was very challenging in terms of its logistics, geometry, space and safety.

An MK motorised formwork carriage with retractable formwork was designed and delivered to achieve optimum productivity. The MK system was used to construct cantilevers in 50 m stretches. Each formwork carriage needed 20 hours to be lowered, moved forward 100 m, lifted and to pour the next tier. To maintain this high pace of work, two more carriages per tunnel were supplied, so that rebar work and the installation of 8 m long reinforcement structures would not limit the pace of other tasks.

The MK system ensured 50 m pouring cycles every 20 hours and also dealt with a 700 mm change in tunnel clearance height. The versatility of the MK system enabled a section transition half way along, thereby demonstrating its leadership in the formwork sector.

The project’s success illustrates how close customer collaboration at the start of a project can ensure results when deadlines are tight.