Crystal Bridges Museum of American Art is a project supported by Alice Walton and The Walton Family Foundation. Her collection, featuring four centuries of American art, is now on display at the recently opened museum. The stunning multi-building museum is nestled in a wooded 120-acre (48.6 Ha) park-like setting within walking distance of downtown Bentonville.
The unique architectural design developed for the 201,000-square-foot (20,200 sqm) Crystal Bridges required several engineering feats including the design of two glass bridges that bookend a pond in the center of the museum landscape. Each bridge has a roof made of locally sourced and fabricated glulam – glued and laminated pine timbers. While glulam arches are typically curved in one direction, this project required that they curve in two planes to create a double curvature of the roof.
The engineers used bridge technology to create the cable-suspended roof structures. To achieve the goal of this unprecedented design, they turned to Ronstan Tensile Architecture.
“Ronstan’s products are integral in supporting the roof, especially under wind and lateral loads – they provided the tolerances the contractor was looking for in this project,” says Cristobal Correa of Buro Happold, who served as Project Lead Engineer. “At the same time, their sleek, slender look contributes to the elegance of the space.”
A total of 650 rods are located in the interior of the buildings, crisscrossed between the glulam beams of the suspended roofing structure. This bracing provides the roof diaphragms for the hanging bridge structure. Diaphragms are designed to transfer the forces of wind, seismic, and lateral loads back to the building abutments. Using bridge engineering principles, the construction team installed anchors in the limestone bedrock to stabilize the surroundings and support the diaphragm system.
Ronstan ARS-4 rods were selected for five of the Crystal Bridges structures. Being only 20 millimeters (3/4 inch) thick, the rods create the needed structural support without detracting from the impressive, massive wooden roofing structure. The suspended nature of the structures, supported by the glulam beams, was accomplished by employing customized rod clevis connections. Ronstan worked with the project team to develop the custom pieces, which allow for extra articulation compared to a traditional fork connection.
“Crystal Bridges Museum of American Art is a great example of how tensile architecture can help to achieve unique engineering and architectural goals,” says Matthew Berrelli, Sales Engineer with Ronstan. “The rod system provides superior strength and support without intruding on the look of the wooden structure. We are thrilled to have contributed to this cutting-edge project.”
Crystal Bridges Museum of American Art won the Metal Architecture Magazine’s 2012 Design Award – Metal Roofing. We are proud and privileged to have been an integral part of this project.