Joshua Tree National Park Carapace Pavilion
The Carapace is a precast concrete pavilion designed for the Joshua Tree National Park that serves both as a shade structure and as a prototype for a double loaded restroom building. It is intended to be placed in a disturbed site that the National Park is looking to redevelop into a campsite. The pavilion is intended to remain in Joshua Tree for over a hundred years. It is a collaborative effort led by the Clipper Lab design-build studio of USC School of Architecture and supported by several consultants, manufacturers, and experts. The project originally intended to use standard precast concrete, and then it developed into glass fiber reinforced concrete and finally settled on ultra high performance concrete. UHPC has a compressive strength of 18,000 as opposed to standard precast concrete which has a strength of 4,000 to 5,000 psi. Furthermore, UHPC does not rely on reinforcing bar for its tensile strength, which presents the opportunity for thinner concrete panels. Although the material has such high strength, it is relatively new and has been used predominately for non-structural building facade applications. The Carapace looks to utilize UHPC’s compressive strength to push the boundaries for thin-shelled concrete structures. Not only is the pavilion relying on the material for its structural strength, but it also pushes the limitations of the thinness of each panel, in some area to 2”.
The design of the project originated from a parametric design tool developed by Ivan Monsreal. Taking into consideration factors such as site conditions, sun shading, structural loads, fabrication and manufacturing methods, and ADA compliance, the final design is a double curved anti clastic geometry. It features a long cantilevered roof to provide increased shading for the desert climate and roof apertures to control the daylighting. The Carapace consists of 5 panels utilizing different sections of a single mold. The mold, which is CNC milled out of high density foam, uses a series of foam attachments and block outs to fabricate different panels out of the same mold. The single mold also prompts a design strategy that responds to the different loads acting upon each piece, whether it is a foundation, wall, or roof.