Amsterdam architects UNStudio have completed a new headquarters for the Dutch national tax offices and the student loan administration in Groningen, the Netherlands.

Called DUO², the 92 metre-tall building has a facade covered in horizontal fins to provide shade and reduce the need for artificial cooling.

The project comprises 2,500 work stations, underground parking for 1,500 bicycles and 675 cars and a public park.

More about UNStudio on Dezeen »

Above photograph is by Ewout Huibers.

Photographs are by Ronald Tilleman unless otherwise stated.

Here are some more details from UNStudio:

UNStudio/ Ben van Berkel, with consortium DUO², realizes one of the most sustainable large office buildings in Europe for two governmental offices.

A greener approach to tall buildings in the post-iconic age - The Education Executive Agency and Tax Offices move to one of Europe’s most sustainable offices.

A new, 92 meter tall complex of soft, undulating curves marks the skyline of Groningen. This asymmetric, aerodynamic construction is set amidst small, ancient woodland, sheltering rare and protected species. The project includes the design, construction and financing of two public institutions; the national tax offices and the student loan administration. The commission from the RGD (National Buildings Service) includes, besides the architecture, the management and building maintenance and care of facilities and services for a period of 20 years. Accommodating 2,500 workstations, parking facilities for 1,500 bicycles and 675 cars in an underground garage, the building will be surrounded by a large public city garden with pond and a multifunctional pavilion with commercial functions.

Above photograph is by Ewout Huibers.

The architecture aims to present these institutions with a softer, more human and approachable profile. Tall buildings are generally associated with mid-twentieth century modernism. Their harsh, businesslike exteriors contain powerful, inaccessible-seeming strongholds. By contrast, the DUO and Tax offices deliberately cloak a commanding public institution in an organic, friendlier and more future-oriented form.

"We paid a great deal of attention to how people would move through the building. The office spaces are designed in such a way that they do not create simple linear corridors leading to dead ends, but instead each corridor has a route which introduces a kind of landscape into the building. You can take endless walks through the building, where there is a great deal of transparency, also towards the surrounding landscape.” Ben van Berkel

Attainability; a mix of affordable and responsible – reaping material benefits of integral design and construction with a Design Build Finance Maintenance Operate Contract

The governmental office complex is built as part of a far-reaching form of public-private partnership (DBFMO) that is designed to effectuate on a more efficient use of public funds. The design, construction, financing, managing and maintenance of the building was hosted by one consortium consisting of Strukton, Ballast Nedam and John Laing. This consortium won the competition for the project on the basis of a combination of esthetic, technical and financial criteria. UNStudio, as the architect of the project, collaborated with Lodewijk Baljon for the landscape design, Arup for the engineering and Studio Linse as the interior advisor.

The life-cycle approach of a DBFMO contract requires that all relevant experts (designers, lawyers, installation specialists, financial specialists, facility specialists) are involved from the start of the project in order to find the best, most cost effective and environmentally-friendly solutions for the continued use and maintenance of the building. This working methodology stimulates not only creative and innovative ideas, but facilitates a reduction of total costs over the entire contract period compared to the traditional means of contracting. In PPP projects contracts are not awarded to the lowest bidder, but to the party with most effective solutions providing the best value for money.

Above photograph is by Christian Richters.

“In a PPP-construction you have to consider all the details concerning maintenance and the sustainable use of the building from the very early stages. It is a unique way to gather all the specialists and the end user around the table from the very outset of the project.”
Ben van Berkel

Exemplary sustainability

“The design contains numerous new innovations related to the reduction of materials, lower energy costs and more sustainable working environments. It presents a fully integrated, intelligent design approach towards sustainability.” Ben van Berkel

The project is one of Europe’s most sustainable large new office buildings. The RGD brief prescribed a future-proof building that couples flexibility and sustainability with an esthetic of sobriety. The architectural response to this has been to strive for an all-round understanding of the concept of sustainability, including energy and material consumption, as well as social and environmental factors. Thus the sustainability manifests itself in reduced energy consumption (EPC 0,74), as well as significantly reduced material consumption. Bringing back the floor heights from 3,60 m to 3,30 m resulted in a total reduction of 7,5 m. on the entire building, which also lessens the impact of the building on the surroundings. Both inside and outside the architecture generates a bio-climate that is beneficial to both humans and the local flora and fauna.

Above photograph is by Christian Richters.

All-round architectural sustainability: a sum of many parts.

Fins
Sustainability and energy reduction have steered the design of the facade, which contains technical installations that are tailored to be durable and cause minimal environmental impact. The facade concept integrates shading, wind control, daylight penetration and construction in fin-shaped elements. These horizontal fins keep a large amount of the heat outside the building, reducing the requirement for cooling.

Concrete core activation
Another technical feature of the building that contributes to its sustainable character is the combination of concrete core activation and underground long term energy storage. This appreciably reduces the demand for external energy sources.

Individual climate control for each workspace
Creating a healthy, energy efficient interior climate and employee workspace comfort was also an important element in the design. Plenty of natural daylight and adjustable heating, ventilation and access to fresh air for individual workspaces contribute to the comfort of the workspaces throughout the building.

The 11-th floor
A high pressure ventilation system with natural air inflow and outflow via main engineering shafts and the facade grills on the 11th floor reduces the need for artificial ventilation

Future possibilities
In addition, the residual energy of the data center and offices can be used to heat the homes that will be realized in the future in the perimeter of the site.

Flexibility
And last, but not least, the building is designed so that it can be transformed into housing in the future without major structural modifications. Therefore, the locations of elevators, stairs and technical spaces have been carefully considered, and a structural grid of 1,20 m. has been deployed, rather than the conventional office grid of 1,80 m.

Conclusion
The inclusion of diverse passive and active environmental and energy efficient solutions has led to a building which is one of the most sustainable office buildings in the Netherlands.

Education Executive Agency & Tax offices, Groningen, the Netherlands, 2006 - 2011

Data:
Client of the consortium:
Dutch Government Buildings Agency (RGD)

Client UNStudio:
Consortium DUO² (Strukton, Ballast Nedam, John Laing)

Program: Office building (phase A); underground parking (phase B); public city garden, pavilion (phase C)

Building surface: 48.040m² offices, 21.000m² parking, 1.500m² pavilion
Building volume: 215.000m³
Building site: 31.134m²

Credits UNStudio:
UNStudio: Ben van Berkel, Caroline Bos, Gerard Loozekoot with Jacques van Wijk, Frans van Vuure, Lars Nixdorff and Jesca de Vries, Ramon van der Heijden, Alicja Mielcarek, Eric den Eerzamen, Wendy van der Knijff, Machiel Wafelbakker, Timothy Mitanidis, Maud van Hees, Pablo Herrera Paskevicius, Martijn Prins, Natalie Balini, Peter Moerland, Arjan van der Bliek, Alexander Hugo, Gary Freedman, Jack Chen, Remco de Hoog, Willi van Mulken, Yuri Werner, Machteld Kors, Leon Bloemendaal, Erwin Horstmanshof.

Designteam:
UNStudio, architecture and interior
Studio Linse, interior
Arup, structure, installations
Lodewijk Baljon, landscaping
Buro van Baar, wayfinding
YNNO, internal logistics
Consultants:
DGMR, acoustics
EFPC, fire prevention
Ingenieursbureau Wassenaar, prefab structure
BTS Bouwkundig Tekenburo Sneek, drawing agency
ISS Nederland B.V, maintenance
Peutz, environmental technology
WUR (Wageningen University & Research centre), ecology
Strukton Bouw en Vastgoed, management and costing
Strukton Betonbouw, construction
Strukton WorkSphere, installations

Financial:
John Laing Infrastructure Limited, financial
RBC (Royal Bank of Canada) Capital Markets, financial
TCN SIG Real Estate Strukton Vastgoed, pavilion development
Allen & Overy LLP, legal
Sequoia, legal