Two very large, prefabricated concrete manhole chambers were delivered to the Grunnavågen VVA project, where the Norwegian municipality Stord is building a new road. With good logistics and coordination, both chambers came into place on the same day.
In recent years, Stord city’s municipal technical facility and its plants have undergone a major development in order to continue progress and upgrading in the years to come. In connection with a new road to the industrial area Grunnavågen, the municipality uses the opportunity to upgrade the water and wastewater infrastructure in the area. They have expanded the main water pipeline to, among other aspects, be prepared for future development of housing and business operations. High on the wish list is also a more stable water supply for the municipality, as well as the opportunity to run the water in a ring pipeline.
Meeting the customer’s needs
In addition to the water and wastewater development, saving space and HSE (health, safety and environment) are important topics. Two prefabricated chambers were chosen as the primary solution to satisfy the needs of the municipality.
For the largest chamber, three fixed AVK combi-crosses were chosen in DN300 together with air valves, dismantling joints and fittings (reduction flanges, flanged pipes and flanged transitions). One combi-cross has a manifold mounted on one of the outlets. This provided the opportunity for water supply through branched pipes to the consumers. Additional shut-off valves were mounted before the air valves for easy maintenance of these. A similar but downscaled solution was chosen for the smaller chamber.
Two heavy lifts
The chambers, including all fittings, weighed 43 and 30 tonnes, respectively. It required good and detailed planning to get them both in place in just one day. They were transported by barges, then lifted by a mobile crane and further on with trailers.
AVK solutions for the project
A combi-cross is a space-saving solution compared to the combination of valves and flanged cross. Also, a fully moulded solution reduces the risk of leaks.
The valves on the AVK combi-cross are of the same high quality as standard AVK gate valves. They are full bore valves and the center outlet allows easy insertion of a cleaning pig.