By Achammer Christoph, Travas Dario, Reiner Horst, Scherl Philipp, Ružičić Nikola, Schlaffer Markus, Haugeneder Michael, Thullner Katharina, Peter Rechberger, Florian Stift, Tobias Hutter, Weingraber Gernot, Krapscha Anna, Mayrhofer Engelbert & Wanas Anton (ATP architects engineers)
The “Smart Urban Upgrade” study, which was carried out by ATP architects engineers in cooperation with students from Vienna University of Technology, systematically examined potential for urban development based on the example of Austria’s Federal Capital of Vienna. The study identified the densification of the existing built urban fabric as a logical, sustainable and attractive option with enormous added value.
Vienna is growing
In the early 1990s around 1.5 million people were living in Vienna. Studies show that the population of Vienna will grow by around another 200,000 between now and 2030.
Potential for development
The increasing demand for individuality and identity is leaving its traces in residential building in the form of an ever wider range of requirements and, as a result, a huge diversity of residential typologies. The need for sufficiency is met by, on the one hand, the optimization of floor plans and, on the other, by the use of standardized, industrial and serially produced elements. This permits both the reduction of costs and the efficient use of space.
A large proportion of the numerous low-rise large-span structures in urban settings are retail buildings. Ever since retail chains have been following uniform marketing strategies which pay little attention to national borders, a uniform building type has emerged, especially in areas where the price of land is low. These buildings are constructed for a useful life of 10-15 years and favor cost-effective delivery, the efficient layout of the retail space and a high level of customer recognition. Construction budgets are tight and there is little room for either architectural added value or sustainable building. These buildings have no relationship with their surroundings and occupy disproportionately large amounts of land.
The study of densification in the urban context covered, amongst other things, the building size, plot size, location, infrastructural connections, urban context and positioning of the retail outlets. A selection of 155 objects revealed a typical building size of between 1,000 and 1,500 m². The plots on which these buildings stand range in size between 3,000 and 6,000 m², are generally rectangular and fine-tuned to meet the requirements of the outlets.
The study uses a representative sample to investigate the typical characteristics of such objects. This enables generally valid quality criteria and influencing factors to be identified which can be used in the search for potential buildings in the future. The study also provides a system for evaluating these buildings.
The potential of the open spaces associated with the selected objects totals 654,000 m² - an area equivalent to around 90 football pitches. Assuming an average development potential of 30% and three stories of residential building this would create 650,000 m² of living space. This represents space for 10,000 three-room apartments of 65 m² and living space for around 30,000 people.
Strategies and areas of application
The typical plan results from the recorded plot areas and building areas of the 155 selected objects. The typical site area is 4,147 m² and the typical building area is 1,289 m² which gives an average number of stories of 0.31. The development strategies discover new spaces above the parking, around and above the retail outlet in various combinations.
System building approach
The search for efficient approaches as a means of quickly and cost effectively making space available has led in the building industry – as in all other industrial sectors - to the development of system-based processes. Residential building is a pioneering example of this phenomenon.
Prefabrication in the factory leads to better cost control and precise timetable management. True quality management becomes possible for the first time in the building industry and can be carried out in the factory.
The high level of complexity is easier to manage and control on the production line. The needs for a site infrastructure are also hugely reduced and construction time is limited to the period required for preparing the site and assembling the prefabricated elements. The dust, dirt and noise pollution which is often so problematic, especially in urban locations, is minimized and a building can start operating very quickly. In addition to this, an optimized production line guarantees high-quality details and standards.
There is a series of approaches depending upon the level of prefabrication: from light skeleton frame construction to element-based construction or modular systems.
Project: Densification above a car park and supermarket
The design is intended as a “master project” based on the average size of site as identified by the evaluation process. This fictional site reflects the combination of access, infrastructure and physical relationships typically found on such sites.
The new built volume floats like a table top above the supermarket and its car park. A generous, unobstructed and manageable space is created in the seven meters below this table top while reflective ceiling elements and openings provide the daylight which lends the space even more quality.
The residential block is designed as a modular system based on a 5.80m grid. This permits variable floor plans at the upper levels. The concept presented here offers 118 modules on 3 levels.
The novel idea of the dual use of the car park also represents an innovative and sustainable approach in this area.