Zoomy Mercedes-Benz Museum Ties Curvy Structure with Complex Spatial Configuration

11/1/2006 By Joann Gonchar

	click images to view larger Although the exterior is clad in aluminum panels (above), the poured-in-place concrete structure of the Mercedes-Benz Museum is almost completely exposed inside the building (below). Photography: © Duccio Malagamba
	The museum’s structural elements include the vertical cores, ramps, “twists,” and four-legged steel columns.
	To test the concrete mix and determine how to achieve a homogenous surface where two formwork elements meet, the construction team built a full-scale mock-up of a twist segment (above). The formwork for the underside of a twist, with ties located, is installed on the building site (below). Photography: © Peri GMBH
	Photography: © Peri GMBH
	The structural configuration of the museum provides column-free exhibition areas spanning almost 100 feet and capable of supporting objects as heavy as buses and trucks (above).
	The museum consists of stacked trefoil-shaped elements, each with two propeller-shaped spaces—one for vehicles and the other for historical displays. Photography: © Peri GMBH
	1. Vertical core 2. Void 3. Car/truck collection 4. Atrium 5. Historical displays

At Stuttgart’s recently opened Mercedes-Benz Museum, UN Studio has created an almost unfathomably complex circulation route. The building borrows the top-down organization of Frank Lloyd Wright’s Guggenheim Museum in New York. But unlike the single-ramp configuration of the earlier spiraling museum, at Mercedes-Benz two ramps intertwine and lead visitors through exhibition spaces arranged propellerlike around a triangular atrium.

One of the two paths takes visitors through a series of five single-story rooms devoted to the car and truck collection. The other route outlines the company’s history in a series of seven double-story rooms (see section, page 130). Each stacked trefoil-shaped floor unit is rotated 120 degrees from the one below it and contains two exhibition areas with floor elevations that differ by about 3 feet.

This twisted (literally) spatial arrangement is integrated with the building’s equally complex poured-in-place concrete structure. The material is almost completely exposed inside the building because it is the ideal backdrop for the exhibits, explains the architect. “The car becomes much shinier in the context of the concrete,” says Ben van Berkel, UN Studio co-founder.

The exhibition-area floors, which are made primarily of concrete but have steel construction at their centers to reduce weight, are supported by the circulation ramps and elements the architect has dubbed the “twists.” These curved box girders transfer the loads between the three vertical circulation cores that rise in the atrium and a series of four-legged steel columns at the building facade. The twists are square in section where they meet the core, but become deformed and sloped as they extend toward the building facade.

The twists, and the building as a whole, are so sculptural that it is often difficult to distinguish one architectural element from the other. “The ceiling slowly transforms into the wall, which transforms into the floor,” says van Berkel.

The configuration of the 270,000-square-foot museum makes possible column-free spaces with clear spans of almost 100 feet and allows for the display of vehicles as large and as heavy as fire trucks and buses. “The span is similar to a highway bridge with the load of a highway bridge” says Werner Sobek, the project’s structural engineer. This point was of particular importance to the client because the building the museum previously occupied did not have bearing capacity suitable for the presentation of commercial vehicles.

Ductwork and other services are integrated directly into the curved twist elements, which contain voids large enough for maintenance-staff access. These mechanical spaces are like “another building woven inside the museum,” says Sobek.

Before construction began, the project team built a full-scale mock-up of one of the twists. Contractors used the mock-up to learn how to form the double-curved surfaces. The process also helped determine the ideal concrete formula and how best to achieve a homogeneous surface where two formwork components joined, according to Jochen Köhler, a project manager for Peri GmbH, the museum’s formwork subcontractor.

The challenge of realizing the daunting project was magnified by the client’s requirement that the building be completed by May 2006, in time for the deluge of soccer fans that would converge on Stuttgart for the World Cup. With about eight months for preparation of construction documents, and two years for execution, “It was one of the speediest projects we ever worked on,” says van Berkel.

In order to complete the museum on such a tight schedule, the design and construction team relied on a building information model shared by all project participants and managed by the consultant Arnold Walz and UN Studio. The ability to read and create three-dimensional drawings was one of the contractor selection criteria, according to the architect.

The data contained in the 3D “mother” model was especially useful to the concrete work. The steel reinforcement encased inside the building’s many compound curves, for example, could not be described in two dimensions. “The length would be wrong due to the ‘map of the world problem,’ ” says Sobek, referring to the distortion that occurs when the spherical shape of the Earth is flattened into 2D.

Spatial coordinates from the model were also used to precisely place the individual formwork elements on the construction site with a global positioning system. “For this kind of building it was the only possible way to bring our elements into position,” says Köhler.

Although it was crucial to the project’s success, the team did not rely solely on the model. “There were parts you had to do in 3D and there were parts you could do in 2D,” says Köhler. Peri used traditional shop drawings to describe pieces of the building that did not contain compound curves and were made with typical formwork components. Köhler says it was most efficient to have the majority of team members “work in their 2D standard way and have a few additional experts that have knowledge and experience in 3D work.”

Van Berkel says that bringing the project to fruition required both traditional 2D drawings and the parametric model, because “construction is not yet as advanced as the car industry” in its use of building information modeling. But, he predicts, the day when a project will be executed without any 2D drawings “is not so far away.”