MAIN TOWER is located in the center of the Financial District and was constructed at the same time like the neighboring Eurotheum tower. Its clear shape and contours give it a majestic appearance. MAIN TOWER was planned by the architects Schweger + Partner and in 1999 it has largely been occupied by Landesbank Hessen-Thüringen (Helaba). Helaba is an integrated universal bank with a strong regional focus, selected international presence, and is tightly integrated into the German savings bank organization. The development of the skyscraper was carried out by OFB Projektentwicklung, a sister company of Helaba.
The 350 million euro complex is made up of many geometric shapes, namely circles and squares. The cylinder is the heart of the transparent building, which extends from base to top. A square building having a height of 177 meters (581 feet) is attached to it. MAIN TOWER rests on more than 100 foundation stones as far as 50 meters (164 feet) deep in the ground.
Up and Down at the Same Time
As early as the planning stage, the architects and engineers who built the MAIN TOWER had to dig deep to come up with innovative solutions for the project. Its proximity to surrounding buildings simply did not allow for a conventional excavation pit, because the load alleviation resulting from the excavated earth from a conventional pit causes the subsoil level on the site to be raised. And this can have a detrimental effect on surrounding buildings. Once this way clear, those responsible took the decision to perform underground construction work under a top cover. Thus, while the excavation pit was being dug, the first few floors of the structure were already being erected above it, and so the tower grew simultaneously in both directions. The extra weight provided by the new stories composensated for the weight of the excavated earth, thus minimizing the increase in the subsoil level.
MAIN TOWER was not constructed step by step, unlike conventional skyscrapers. Instead, the individual construction stages were largely completed in parallel operations. Once the shell of the first few floors above ground had been erected, the glass facade was fitted, enabling interior construction work to commence without delay. After the technical, sanitary and heating installations had been put in, attention turned to the offices, reception rooms and common areas. While all this was going on, building work was continuing on the shell above. This resulted in a relatively short construction time of just 29 months.
The curved window facade of MAIN TOWER is unique in Germany and is not just pleasing to the eye, it also boasts many innovative elements. The most important innovation is the windows themselves, which can be opened individudally in accordance with the prevailing weather conditions such as wind, precipitation, temperature, etc. to provide natural ventilation throughout the offices.
MAIN TOWER has been designed as an extremely energy-efficient building. For instance, a part of the tower’s general-purpose current supply (e.g. for elevators and general lighting) can be produced in block-type thermal power stations as a by-product of heat generation. Moreover, cold air can be stored in the ground under the building in winter and drawn up for air-conditioning purposes in the summer. It reaches the offices via a piping system in the foundation piles, coupled with the use of heat exchangers.
Open to the Public
On the top floors are a restaurant and a bar, which are open until late evening. On the roof there is a viewing platform, where you can experience Frankfurt ‘from above’. You can reach the roof by way of one of the fastest lifts in Germany, which moves at 7 meters (23 feet) per second. At the top, there is a widely visible 40 meter (131 feet) high antenna. During bad weather you can still visit the top from the inside.
Status September 2001: MAIN TOWER receives the LEED GOLD certification for existing buildings. LEED (Leadership in Energy and Environmental Design) recognizes buildings that are exemplary in their use of resources.
Status October 1999: MAIN TOWER is in the final stages of completion. The skyscraper of Helaba and OFB greatly contributed to the acceptance turn of high-rise construction in Frankfurt, because with it tall buildings began to be publicly open for the first time.