Königshof water storage reservoir
New construction in Rüttenen subject to strict Swiss safety requirements
The notoriously strict Swiss safety requirements are not the only challenges being faced by the contractor.
In the Swiss municipality of Rüttenen a new drinking and process water reservoir is under construction. The notoriously strict Swiss safety requirements are not the only challenges being faced by the contractor.
A regional energy supplier commissioned Marti AG with the construction of the Königshof reservoir. The reservoir with a storage capacity of 6,000 m³ is intended to safeguard the regional drinking water supply for at least the next 100 years and also ensure that water is available for firefighting purposes. Once complete, the new construction will replace two obsolete facilities and will no longer be visible, but rather well hidden below ground. In February 2021, the team led by construction manager Liridon Haxhimurati and foreman Peter Kaufman started the concrete construction work. The prestigious construction company relied on the high performance of the Mammut 350 wall formwork, the safety provided by the SecuritBasic system as well as the simple handling of CaroFalt to create the columns.
The excavation of the construction pit with a length of 60 m, a width of 30 m and a depth of 13 m was completed In January. Removal of the very hard mineral rock of the “Nagelfluh” wall was challenging and time-consuming. The concreted reservoir has surface area of 51 x 26 m. Correspondingly little space remained for installation work, storage and material maintenance on the cramped construction site in the middle of the countryside, only accessible via a forest track. Especially the installation of the high formwork and the assembly of the SecuritBasic safety system were demanding due to the given spatial constraints. For this reason, several Mammut 350 panels were joined together to produce a height of 7 m and, together with the SecuritBasic safety system installed over three storeys, were simply relocated by crane once the concrete had set.
One of the project’s distinctive features was the forming of the very thick corner walls, which were poured with a 45° angle on the inside to reinforce them. In order to withstand the high forces in these corner areas, Mammut 350’s permissible fresh-concrete pressure capacity was reduced from 100 kN/m² to 80 kN/m². The construction was reinforced further by means of corner braces manufactured by MEVA especially for this purpose so that the formwork was able to withstand the high pressure in these difficult areas. Mammut 350 and the CaroFalt column formwork were covered with fleece formwork sheets to drain excess water from the concrete surface. Water stops were left in the tie holes as irrecoverable parts after pouring.
On construction sites in Switzerland the strict safety regulations issued by Suva (the Swiss national accident insurance fund) are compulsory, and for the Königshof reservoir project the requirements and guidelines of SVGW (the Swiss association for the water and gas sector) also apply. The Marti construction companies are familiar with the MEVA technologies from a great many joint and also very challenging projects.