OpernTurm
OPERNPLATZ – RESTORATION OF A CITY COMPLEX
During World War 2 the towns and cities of Germany suffered not only the destruction of many of the buildings important to the country's history, but above all the uniqueness of historically important sites, squares and streets. In Frankfurt am Main the only open urban space to escape severe damage was Opernplatz, which had been laid out in the 19th century. But here, too, the magnificent opera house itself survived only in the form of a totally burnt-out shell.
During the decades of rebuilding this last remaining historic urban space was finally condemned to the history books as all the buildings on the western side of the square were torn down. They were replaced during the 1960s by individual high-rise blocks linked by low-rise structures according to the town planners' notion of the "urban landscape" – facades of glass and aluminium covering one-third of the adjoining Rothschild Park and thus cutting it off from the city.
The demolition of these buildings and the construction of the new OpernTurm presented the City of Frankfurt am Main with a great chance to restore this prestigious 19th century square to its original form as an enclosed city complex. The urban ensemble owed its unity to the yellow-beige stone facades of the various buildings around the square, facing the opera house of yellow sandstone in the middle. And that was the starting point for the new development. A perimeter block of yellow stone with horizontal fluting, matching the height and materials of the original buildings. It complements the existing buildings around the square and forms a coherent urban space once again. Employing a typical urban style ingredient from the 19th century, the new perimeter block includes two-storey arcades with shops and restaurants, thus restoring to the western side of the square the vitality it once enjoyed.
RESTORATION OF ROTHSCHILD PARK ACCORDING TO ORIGINAL DRAWINGS
The original layout of Rothschild Park will be restored as part of a major refurbishment programme. The building of the OpernTurm allows half of the plot, up until now a paved area of 5500 m2, to be returned to the open green spaces of the park. This almost forgotten park will once again provide a spacious recreational area for the city centre. The areas of planting and landscaping will allow valuable rainwater to seep into the ground, and their ability to absorb heat better will also help to reduce the occurrence of urban heat islands in the city centre. Furthermore, some 30 000 m2 of the park grounds will be redesigned and replanted.
CLASSIC, ELEGANT HIGH-RISE ARCHITECTURE
The tower employs a classic design: inviting, four-storey entrance foyer, central section with offices and striking end section with "city loggia". With a height of 18 m, the proportions of the entrance foyer are unique in Germany. The four deep, vertical slits in the tower facades give the tower its elegant proportions.
Departing from the customary glass facades, the exterior of the building is finished in a natural material – a light-coloured Portuguese limestone that harmonises with the opera house and the existing buildings on the edge of the square. Despite the stone cladding there is still a large proportion of glass. The vertical alignment of the windows lends the stone facade a lightness and aspiring eminence. Lesenes, vertical projecting pillars of masonry between the windows, give the external cladding its fine contours, and also guarantee shade and hence an appearance of depth on the facade of the high-rise block.
MAXIMUM FLEXIBILITY THANKS TO UNINTERRUPTED INTERIORS
Reinforced concrete and composite steel-concrete construction was used for the loadbearing structure. The floor loads are carried by the central service core and columns integrated into the facade. This means there are absolutely no columns in the interior, which results in excellent flexibility when planning the interior layout.
COOLING ENERGY REQUIREMENTS CUT BY 20% THANKS TO STONE FACADE
At the same time, more than 50% of the facade is closed, which together with the highly efficient glazing reduces the solar gains and hence the need for mechanical cooling. Vertical lesenes projecting from the facade between the windows create a passive shading effect: compared to an all-glass facade, the stone facades of the OpernTurm project therefore save 20% of the energy normally required for cooling an office floor.
OPERNTURM BUILDING LIES 23% BELOW ENERGY VALUE REQUIRED BY LEGISLATION
Energy performance certificate
The excellent energy values of the OpernTurm project are 23% lower than the values required by Germany's 2007 Energy Conservation Act. That means a saving of 1800 t of carbon dioxide every year.
Lighting
Energy-saving lighting units with individual controls and the controlled ingress of ample daylight together reduce the energy consumption.
Heating
The OpernTurm complex is connected to the district heating network. The heat in this system is a by-product of electricity generation, consumes only half the amount of primary energy and also cuts emissions by 50%.
Cooling
A hybrid heating/cooling ceiling cools the concrete core of the building during the night and in doing so uses 30% less energy than conventional cooling ceilings. The refrigeration plant employs Turbocor compressors combined with conventional compressor technology. That increases efficiency and cuts electricity consumption. During the winter the refrigeration plant is replaced completely by "natural cooling".
Ventilation
Natural ventilation via the windows is possible for most of the time that the offices are occupied; forced mechanical ventilation is unnecessary during working hours. The supply of fresh air can be controlled individually at all times, throughout the year, without automated, central "overcontrol". The unobstructed ventilation cross-sections were designed according to the requirements of Germany's places of work legislation and are above the minimum values. The climate concept for the lobby was optimised by way of CFD (Computational Fluid Dynamics) simulations, which resulted in further energy-savings.
Recycling
All the construction debris was reused and the use of recycled materials, e.g. aluminium, was encouraged. Transport emissions were kept as low as possible; for example, the use of reusable steel transport frames or 100% recyclable polyethylene sheeting.
OPERNTURM TO BE AWARDED LEED GOLD STATUS
The OpernTurm building will be one of the first new-build office towers in Europe to be awarded the LEED (Leadership in Energy & Environmental Design) Gold Certificate of the U.S. Green Building Council.
PROJECT DEVELOPMENT Tishman Speyer Properties Deutschland GmbH
PRINCIPAL TENANT UBS Deutschland AG, since January 2010 (approx. 29 000 m2)
OTHER TENANTS
Allen & Overy LLP,
Ashurst LLP,
Blackrock Investment Management
,
Cerberus Deutschland Beteiligungsberatung GmbH,
Excellent Business Centers GmbH,
3i Deutschland,
K+L Gates LLP,
Manufactum,
Morgan Lewis & Bockius LLP,
PLOT SIZE approx. 10 300 m2
LETTABLE SPACE total: approx. 66 000 m2
HEIGHT OF TOWER 42 storeys, 170 m
PARKING SPACES 580 (250 thereof for the public)
START ON SITE autumn 2006
COMPLETION winter 2009
HOAI PHASES 1–6, artistic supervision 8
HEIGHT OF TOWER 42 storeys, 170 m
PARKING SPACES 580 (250 thereof for the public)
START ON SITE autumn 2006
COMPLETION winter 2009
