A few years ago, those responsible for the city of Sankt Gallen came to the conclusion with the local trade fair company OLMA that, despite the limited space available, it was important for the city’s identity to continue to keep the trade fair in the center. An increased focus on congress and event tourism was unthinkable at the time. However, by covering the highway directly adjacent to the trade fair area, space could be created for another trade fair hall with dimensions of 90 x 150 meters.
This new Hall 1 will contain a foyer with over 3,800 m2 and a column-free floor space of 9,000 m2. However, in order for the hall to be built, a cover must first be constructed over the roadways and the existing highway tunnel must be extended – a challenge with a traffic volume of 100,000 trips per day. The planners were aware that the construction work could only take place at night with the lanes closed.
The Swiss heavy-lift company EMIL EGGER AG, known as ETE for short, which has been operating in St. Gallen for 90 years, was involved in the logistics planning early on. Due to the tight space conditions around the construction site, the assembly of the prestressed concrete girders by means of a mobile crane from the A1 was initially considered. However, this would have meant having to place a crane of the 300 to 500 t category on the highway every night and only max. 4 porters per night to be able to collect.
LR 11000 on four large bore piles
In the course of the project, a deconstructed building next to the highway freed up a few square meters. ETE proposed to use this space, as the LR 11000 placed there would significantly reduce the number of night closures and could be operated efficiently from the first minute of closure. Those responsible were immediately convinced and from then on the team and the specialists around the business manager of the heavy lift division Michael Egger were challenged. Thus, the 1300 t crawler crane had to be positioned on four large bored piles due to insufficient load-bearing capacity of the subsoil and in order not to endanger a neighboring railroad tunnel. The task was to cover the entire construction area from there. After several detailed studies, project manager Andreas Schönenberger had found the ideal location and at the end of September, the crane in the SL2DBV configuration with 144 m main boom was rigged not far from the company’s premises. Thanks to the V-Frame, successfully in use at ETE for over two years, the work could be carried out smoothly even in the confined space conditions. However, main crane operator Peter Stricker had to rely heavily on the information provided by his colleagues via radio, as the work was taking place in the cut of the highway below.
Relevant load cases: 64 t gross at 124 m projection
Even the roller head camera was of little help. However, in his usual calm manner, he said, “With the right team, such a task is not only exciting, but also fun.” The relevant load cases were 64 t gross at 124 m throat and in the closer area 87 t gross at 108 m throat. Between 8 and 13 carriers were placed per night. Everyone involved was amazed that it is possible to work so efficiently and precisely even with such a large crane.
The EMIL EGGER team is already looking forward to further challenges from its modern crawler crane fleet, which has just been supplemented by an LR 1700-1.0. The new Hall 1 is scheduled for completion by the end of 2023 and will then offer space for up to 12,000 people.