This year’s Serpentine Gallery Pavilion opened last Saturday as the 13th in the gallery’s series of temporary installations highlighting design. Designed by Japanese architect Sou Fujimoto with engineering work performed by Los Angeles-based AECOM, the pavilion has a translucent, cloudlike shape created from 27,000 steel tubes that are square in cross section. Iwan Baan
This year’s Serpentine Gallery Pavilion, designed by the architect Sou Fujimoto with engineering by AECOM, combines linear components in an ethereal arrangement.
June 11, 2013—Saturday marked the official opening in London of the Serpentine Gallery Pavilion, designed this year by the Japanese architect Sou Fujimoto with structural, electrical, and lighting engineering work provided by the Los Angeles–based firm AECOM. This is the 13th pavilion to open since the program began, in 2000, and this year’s structure combines tight lattice steelwork with an amorphous, organic shape to create a pavilion that is the most literal marriage of architecture and engineering to appear on the gallery’s grounds so far. And even though it uses 12.5 metric tons of steel, it is also the lightest and most playful pavilion yet created.
Each year the Serpentine Gallery invites a world-renowned architect who has not yet had a structure constructed in the United Kingdom to design a temporary pavilion with gathering spaces that can be used by the public during the day and can host events during the evening hours, including concerts, talks, movie screenings, and performances. This year the luxury department store Fortnum & Mason, which has a history stretching back to 1707, will host a café within the pavilion.
This year’s pavilion used 27,000 steel tubes 20 mm square in cross section with a wall thickness of 2.5 mm to create the “translucent, cloudlike nature,” of the pavilion, which structurally works as a three-dimensional Vierendeel truss, says Tom Webster, CEng, MIStructE, an associate director in the London office of AECOM and the lead engineer on the project. Overlapping clear polycarbonate disks with diameters of 1.2 and 0.6 m are clamped to the top of the structure to protect the interior from rain, and internal and external fritted glass has been added to the steel grid in various places to create areas for lounging, climbing, and standing.
Fully integrated building information modeling (BIM) made it possible to create the approximately 24 m wide and 7 m high cloudlike structure, which has a total area of 357 m2, according to Webster. Despite the volume of steel tubes used in the design, relatively few actually carry the structure’s loads, he says. “It’s a very efficient, lean design in terms of the actual structural engineering,” he notes. The load-bearing tubes did not need to be thickened or strengthened because the load path was created through strategic placement of the tubes and joints to form the grid. In creating and analyzing the design, the architects and engineers used a number of three-dimensional computer modeling and analysis programs, including Rhino, produced by Seattle-based Robert McNeel & Associates, and Scia Engineer, produced by Nemetschek Scia nv, of Belgium.
Cutouts in opposing hollow tubes allow the larger, welded
modules that form the pavilion to be fitted together on-site like
puzzle pieces. A steel rod placed inside the tubes preserves
strength in the connection. AECOM
The contractor, Stage One, which is based in York, United Kingdom, and was responsible for the distinctive cauldron structure for the London 2012 Summer Olympics, welded together tubes in its fabrication studio to create 56 individual modules, each 400 by 800 mm. Once on-site, these modules were connected together to form the pavilion.
“I think what’s interesting about this pavilion is that the pavilion itself is a structure. There’s not really a cladding to it, and there is no real shroud to hide the structure,” Webster says. This complete integration required specialized hidden joints that could be completed on-site to connect the welded modules. “It was very important to us that the detailing of the steelwork met with the architect’s aspirations, rather than it being a series of plates and bolts connecting things together,” Webster says. “I think a lot of people don’t necessarily notice good engineering, but they will notice bad engineering.”
The hidden joints were created with what Webster calls “halving” joints, for which cutouts were made in opposing hollow tubes so that they would fit together much like puzzle pieces. A steel rod was placed inside each tube so that the modules could be slotted together without a loss of strength, and screws were then placed through the tubes and rods with a specialized drill bit. The edges of the screws were ground down, completing the joint without the need for on-site welding. The entire structure was then painted with a white, two-part epoxy paint.
Webster explains that forming the joints in this manner has an additional benefit that is particularly important for a temporary structure: “It allows us to drill out those bolts and pull the structure apart and then take it somewhere else and reerect it without the need to keep cutting and rewelding sections.”
Internal and external fritted glass was added to the steel grid in
various locations to create areas for lounging, climbing, and
standing. The pavilion will contain a café and can be used for
evening events, performances, and movie screenings. Iwan Baan
The pavilion sits upon a 275 m2 concrete raft foundation that is 150 mm thick and is surrounded by 206 m2 of gravel stones placed to accommodate rainwater drainage from the top of the structure. Last year’s pavilion, a Herzog & de Meuron design developed in collaboration with the Chinese conceptual artist Ai Weiwei, involved significant excavation, something this year’s design had to take into account. “They dug a very large, 2 m deep hole, and the ground has not really recovered and is not very strong,” Webster says. “So, distributing the load across the foundation of the whole area of the site is better in terms of limiting the long-term settlements on the structure.” (See “Art Pavilion Celebrates Archaeology, Olympics,” on Civil Engineering online.)
The annual program to create the pavilion is tightly scripted, a mere six months separating the selection of the architect from the official opening of the pavilion. Many of the biggest names in architecture have completed designs, including Peter Zumthor (2011); Jean Nouvel (2010); Kazuyo Sejima and Ryue Nishizawa, of SANAA (2009); Frank Gehry (2008); Olafur Eliasson and Kjetil Trædal Thorsen (2007); Rem Koolhaas and Cecil Balmond (2006); Álvaro Siza and Eduardo Souto de Moura with Cecil Balmond (2005); MVRDV (unrealized, 2004); Oscar Niemeyer (2003); Toyo Ito and Cecil Balmond (2002); Daniel Libeskind (2001); and Zaha Hadid (2000).
This is the first year that the London office of AECOM has handled the structural engineering for the pavilion; the London office of Arup did the work for each of the previous pavilions. This is the fifth pavilion that Stage One has constructed for the gallery. The pavilions attract more than 300,000 visitors annually and regularly feature among the top 10 architectural and design exhibitions worldwide, according to information at the gallery’s website.