A VARIOKIT tunnel formwork solution accelerated construction progress for the 228 m long Marchlehner gallery, situated at a height of 1,800 m above sea level. The competent planning took into account all possible project requirements which ensured on-schedule completion before the onset of winter.
The village of Vent is located 1,900 m high in the Ötztal Alps and – in contrast to the nearby winter-oriented ski resort of Sölden in the Ötztal Valley – has established itself as a popular attraction for mountain climbers and is open all year-round. The only road connection passes through the narrow Venter Valley with a number of gallery constructions guaranteeing safe access for visitors by providing protection against avalanches and falling rocks.
With the completion of the Marchlehner gallery at the end of 2013, the L 240 road between Sölden and Vent can now be safely negotiated along the complete route. The 228 m long tunnel construction closes the gap between two existing galleries. The cross-section of the gallery measures 9.20 m x 4.90 m in the road axis direction and features an inclined supporting column structure with discontinuous wall buttresses on the valley side.
For realizing the gallery slab, the experienced Teerag-Asdag AG (Tyrol subsidiary) construction crew used a tunnel formwork carriage on the basis of the VARIOKIT engineering construction kit. In addition to the short construction schedule, the challenge was to take into account the relatively high volume of traffic of around 1,000 vehicles per day during the actual execution of construction work. In order to ensure that traffic – including trucks and buses – could pass through the formwork carriage during all stages of construction without restrictions, PERI engineers together with the site management designed a customized project solution. This was also very cost-effective due to the use of mainly standardized and therefore rentable VARIOKIT system components.
The formwork concept consisted of a 13.50 m long slab formwork carriage with a 3.00 m wide and 4.50 m high access portal, as well as four craneable formwork units for the valley-side 1.50 m cantilevered tunnel slab. In order to ensure that the total of 19 tunnel sections were completed on time before winter set in, two standard cycles each 12 m long were formed, reinforced and concreted per week on average. Hydraulic operations as well as the very light 35 t construction weight resulted in a fast moving procedure on each occasion by means of heavy-duty rollers – in spite of the extremely steep incline of around 8 % in this section of the route. In addition, the VARIOKIT formwork carriage could be easily adapted to the changing radii of the S-shaped gallery with the help of the integrated transverse launching units.
PERI delivered a wide range of prefabricated formwork and construction units to the jobsite which meant valuable time advantages could be achieved right at the beginning of this project. Last but not least, the planning and execution of the stopend formwork, including accommodation of the water stop, were integral parts of PERI´s comprehensive overall solution. In this way, numerous time-consuming working steps on the construction site could also be saved.