Phæno Science CentreWolfsburg Germany

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Project Phæno Science CentreLocation Wolfsburg, GermanyArchitecture Zaha Hadid Architects & Mayer Bahrle Freie ArchitektenProject Architect Christos Passas (ZHA)Structural Engineers Adams Kara Taylor with Tokarz Frerichs LeipoldProject Engineer Paul Scott (AKT) with Lothar Leipold (TFL)Services Consultant NEK & Buro HappoldConcrete Contractor HeitkampLighting Contractor Fahlke & Dettmer, Germany; Office for Visual Interaction, USAPhotographer Helene Binet

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issue 04 Phæno Science Centre

Zaha Hadid

issue 04 Phæno Science Centre

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Zaha Hadid

issue 04 Phæno Science Centre

issue 04 Phæno Science Centre

Unstable by themselves, the cones are locked in place by the weight of the distorted concrete box they support. For the space beneath, Hadid conjured an undulating pedestrian plaza where the pavement ramps and dives to direct different paths of circulation. At one point the pavement rises to meet the bookstore entrance; at another it sinks to steer visitors to an open plaza directly under the belly of the building. A sinuous blue strip embedded in the pavement guides pedestrians through the plaza toward a narrow bridge crossing the canal into Wolfsburg.

“The Phæno is the most ambitious and complete statement of our quest for complex and dynamic fluid spaces,” Hadid says.

“The visitor is faced with a degree of complexity and strangeness,ruled by a very specific system based on an unusual volumetric structural logic. Floors are neither piled above each other nor could they be seen as a single volume…the mass is supported and also structured by funnel-shaped cones protruding into it and extending from it. Through some of these funnels the interior of the box is accessible – others are used to lighten the space inside, while some of them house necessary functions,” she says.

“Phæno combines formal and geometric complexity withstructural audacity and material authenticity. A lot of time and energy was concentrated on achieving this result.”Whatever you make of Hadid’s architectural gymnastics, Phæno is also remarkable as a showcase for the plastic possibilities of concrete and the application of new technologies to make the probably unlikely possible. The new technology came in the form of self-compacting concrete in which chemical additives are introduced into the concrete mix, significantly increasing its workability without any resultant loss in strength. Cast from 27,000 cubic metres of self-compacting concrete, the physical reality of Phæno is that it is one of the world’s largest examples of virtually hand-crafted, seamless insitu concrete – as much landscape as architecture – comprising the 12,000sqm main exhibition space above, a 15,000sqm underground carpark, with the public plaza in between. Working in collaboration with engineers Adams Kara Taylor, Hadid conceived the three spaces “of a piece” involving constructional realization that had been previously unattainable in the conventional terms of supports, girders and roofing.With spans up to 50 metres between the irregularly distributed cones and with significant cantilevers reaching out to the building’s perimeter, the project represented a unique challenge; not only with the raised exhibition space twisting in plan within a distorted 150metre x 90metre grid, but also with the tapering and leaning cones adding eccentric loads into an already complex equation.AKT’s Paul Scott, describes Hadid’s concept as that of a floor space melting down into the ten cones, with their geometry undefined. “Without self-compacting concrete, the building’s diverse plastic forms – its jagged angles, looming curves, fractured planes and daring protrusions – would have been difficult to achieve,” he says.To satisfy the Hadid design team’s rigorous pursuit of authenticity and structural efficiency, a computer modeling process was developed, using AKT’s finite element analysis software, to enable the complex forces within a single element to be resolved, reducing the volume of the concrete to its absolute thinness.

“Without advances in computer modeling this would have beenvirtually impossible a few years ago and the building would have been engineered in the traditional manner, broken down and engineered as separate structural systems which, when combined, would have produced a significantly over-designed structure, with walls twice as thick” Scott says.

“Instead, the cones, slab and façade act together as a singlestructure. The façade is sometimes being supported by the slab, and sometimes it is supporting the slab. The cone walls are inclined up to 50º which blurs the boundary between walls and floors.” This blurring also occurs in the relationship between the cone and the slab. Although the cones are the main support for the building, they also depend on the slab for restraint. “The building is fooling itself a lot of the time,” Scott says.Since the building was designed to appear as a single mass – to simultaneously create space, void and structure, with walls inclined up to 50º from vertical – the self-compacting admixture in the concrete enabled continuous concrete pours of up to seven metres high, for heavily reinforced walls just 300mm thick, within timber formwork in which it would have been difficult to use traditional compacting methods. Continuous concrete supply was also crucial for the big pours, as the admixture in the concrete has a tendency to accelerate the hardening of the concrete. “The benefits outweighed trying to use conventional mixes,” Scott says. “It produced a finish that would have otherwise been impossible to achieve through general construction techniques.” JR

For here, in Germany’s car city – Wolfsburg is home to Volkswagen – the woman who Rem Koolhaas described in 1976, in her final year at the AA London, as “a planet in her own inimitable orbit… it will be impossible for her to have a conventional career”, has made real in an actual building architectural ideas that previously could only be guessed at through her wild and fanciful paintings.After a string of seminal works – among them a fire station, a tram terminus, a ski jump and a small museum, and the 2004 Pritzker Prize for Architecture, she has delivered the goods with this, her first major mature building. And what a building! What Frank Gehry’s Guggenheim did for Bilbao, the Phæno will surely do for this small industrial centre trying to reinvent itself as more than just a car town.Rising on the site of a former carpark just east of Wolfsburg’s railway station, with the mile-long VW plant to one side of the Mittellan Kanal and residential sprawl on the other, Phæno is unlike anything else in this industrial city. And while it sits at the endpoint of a chain of important buildings by Alvar Aalto, Hans Scharoun and Peter Schweger it is distinctly of today and of a style conjured only in Hadid’s extreme imagination.Propped on ten giant cones of steel reinforced concrete eight metres above an open public space connecting the two halves of the city, the distorted three-sided concrete box looks wild and alien, an extra-planetary mothership maybe or a mysterious creature come to check out the lie of the land, ready to scoot at a moment’s warning. Six of the cones support the box, while the other four pierce the floorplate to sustain the complex swooping steel framework supporting the roof. Slung over the interior’s column-free landscape, this massive grid structure stands in stark contrast to the fluid simplicity of the museum’s concrete floors and walls. The cones also act to house functional spaces like a bookstore, a conference room, a 250-seat theatre and the museum entrance inside the largest of them. Entering on a soaring escalator, visitors are transported up and into an architectural interactive adventure playground where floors meld seamlessly into walls, to discover an inhabited landscape of craters, caverns, terraces and plateaus in which to explore thrilling themes from the world of science and technology.

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The Phæno Science Centre in WolfsburgGermany is remarkable for more than Zaha Hadid’s radical take on her notions of what a sciencemuseum should look like. ≥

issue 04 Phæno Science Centre

Forming the conesThe formwork for the cones consisted of planed boards, with the joint pattern and nail positions of the trapezoidal boards specified as accurately as the locations of the tie bar holes. The prefabricated formwork elements were artificially aged with a cement wash on site. As the cones open out upwards, the outside formwork panels – that is the exposed concrete formwork face – had to be erected first and supported on the underside with heavy duty props. The reinforcement was placed and tied together on this formwork before the inner formwork panels were erected. The release agent, a formwork wax which proved to be particularly weather-resistant in several tests, was sprayed on to the formwork. In view of the complicated shape of the reinforcement cage, the spacer blocks for the starter bars for subsequent pours were exactly positioned and fixed in place with the aid of templates. The spacer blocks posed a problem for the exposed concrete wall surface, whereby the weight of the reinforcement pressing into the solid wood boards caused defects – spacer block pimples – in the exposed concrete, which were very noticeable after stripping. To tackle the problem, a detail was developed on site that allowed the formwork tie bar cones to also act as spacers. Excerpt from Exposed Concrete – Technology and Design (Birkhauser 2005)

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Paul Scott

issue 04 Phæno Science Centre

Project Statement The process of achieving a well designed building involves a considerable amount of time and effort in the details. Not just the traditional notion of connection details but the material details of the project and how they are put to use. An example of this in the Phæno Science Centre project was in the development of the design and construction of the cone structures. The project involves the use of ten tapered cones which rise from the foundation level to provide support to the raised exhibition floor. At the main exhibition level, six of the supporting cones terminate whilst the remaining four continue through to support the roof level above. The result is a structural interaction between the inclined surfaces of the walls and floors. Each cone has a unique form and comprises of a plan geometry, which varies in height. The cones provide the only structural support to the building yet also house accommodation and services and are thus penetrated and cut by openings in relation to both these functions. Given that the cones were constructed of insitu concrete with the external face exposed, it was important architecturally to cast the concrete in one continuous pour between external floor plates to avoid visible pour lines on the exposed external surface. This involved pours of seven metres high with walls inclined up to 50º from the vertical. This led to two immediate problems: The pressure of wet concrete exerted on the formwork during the pour; and the control of concrete compaction and finish, given the complexity of the inclined walls and the extent of penetrations. The first problem can be solved in the design of the shutters both for the increased pressure and in the design and sealing of joints to avoid bleeding.The second problem is traditionally more difficult to solve and would have involved guiding vibrators up the inside of the shutters through a series of tubes in order to ensure adequate compaction of the concrete. The complex opening profiles would have made this process more difficult and together with the angle of the inclined walls posed a risk to the as-struck finish. This led to consideration of self compacting concrete as a means of dealing with these problems. Self compacting concrete is created by the use of chemical additives introduced into the mix at the batching plant. It was originally developed in the Far East for early strength gain but was soon found to exhibit other properties which benefit the placing and casting of the concrete. It enhances the properties of the concrete by creating a mix with high workability; maintaining a cohesive mix avoiding segregation; reducing shrinkage through reduced water content; increased durability; and increased strength.The process to construct each cone was initiated by the erection of the outer shell, followed by fixing of the reinforcement layers and then the inner shell. Each form was completed between pour levels together with all service and architectural void formers prior to the pour. As the concrete has a quicker setting period, it is important to ensure that continuous supply of concrete is available to complete the pour. Failure to do this will result in the formation of cold joints (a higher risk in self-compacting concrete due to the quicker setting times). The process worked well on site with few problems. The formwork shutters were removed after three to four days, with propping remaining in place until the upper floors had been cast and the structure was tied together in its final form. All cones used a plywood finish, which helped absorb some of the air which would normally be trapped at the surface with a steel shutter. Above ground level a further treatment was applied to the inside of the timber form by using a pattern of vertical wood strips which provided a further testament to the ability of self-compacting concrete to allow the use of fine finishes on complex forms. The main exhibition level takes support from the cones and provides level changes via its own folding form. From ground level the underside of the floor slab is exposed displaying a changing waffle density. The waffles are laid out and concrete poured over and around them to create a series of ribs and a floor slab over but without the dead weight of a solid 900mm slab. Where waffles can’t be seen, void formers are still used to reduce the self weight of the slab. The form of the waffles is skewed to reflect the overall geometry of the exhibition floor plate. The pocket area bifurcates the main exhibition slab into a lower and upper area. In this instance, the waffle floor takes the lower level and is reflected in the exposed structure below and a thinner solid slab rises to form the upper part of the pocket. The exhibition floor cantilevers beyond the perimeter of the supporting cones to the edge of the upper floor plate and provides support to the perimeter walls and façade above. Propping of the main exhibition floor was maintained until all the cones and floor plate had been completed and the structure was stable in its own right. As some of the cones were unstable until the exhibition floor had been completed, the cones worked as a group. The steel roof structure consists of a fanning truss arrangement based on a two-way spanning vierendeel which rises and falls to create its own landscape. Support is taken from just four of the concrete cones and the perimeter steelwork, providing an exhibition space clear of obstructions. Paul Scott – Adams Kara Taylor

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Zaha Hadid

Phæno Science CentreWolfsburg Germany

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Project Phæno Science CentreLocation Wolfsburg, GermanyArchitecture Zaha Hadid Architects & Mayer Bahrle Freie ArchitektenProject Architect Christos Passas (ZHA)Structural Engineers Adams Kara Taylor with Tokarz Frerichs LeipoldProject Engineer Paul Scott (AKT) with Lothar Leipold (TFL)Services Consultant NEK & Buro HappoldConcrete Contractor HeitkampLighting Contractor Fahlke & Dettmer, Germany; Office for Visual Interaction, USAPhotographer Helene Binet

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issue 04 Phæno Science Centre