LeMay Museum

When entering the exhibit hall at the new LeMay Museum in Tacoma, Wash., visitors may find themselves gazing up at the ceiling as well as taking in the lines of gleaming classic cars. A soaring roof system made with curved glulam beams offers a striking sense of grandeur while simultaneously lending a warm, grounded aesthetic to the vast space.   Nicknamed “America’s Car Museum,” the 165,000-square-foot facility was created to celebrate America’s love affair with the automobile. Across its 4-story, 9-acre campus, the museum will house up to 350 cars, trucks, and motorcycles from private owners, corporations, and the expansive Harold LeMay collection, from a 1906 Cadillac Model M to a 1965 Lotus racecar to a 1983 DeLorean DMC 12. Rotating exhibits, such as a collection of glass hood ornaments, also will be showcased.

Along with displaying some of the world’s most awe-inspiring vehicles, the museum will also serve as a gathering place for car enthusiasts, with meeting spaces, a membership club, a show field and a planned educational center.   The museum’s main hall is essentially a long exhibit floor, almost warehouse-like, but aesthetically enhanced with its wood structure and thoughtful display details. Engineered by Western Wood Structures, the curved roof system was created with 19 glulam frames with 5-1/8-inch glulam purlins spaced 4 feet on center as secondary framing.

The glulam beams, crafted by American Laminators, measure 8-¾ inches by 52-½ inches and arc 104 feet over the displays below. Because the roof curves in two directions, each of the 757 roof purlins is unique, with varying compound miter cuts and varying lengths; each purlin hanger has a different skew and slope.   One-and-one-eighth-inch fully sanded plywood sheathing from Swanson Group Mfg. LLC covers the roof, with ½-inch and 5/8-inch sheets used around corners to meet the 1-1/8-inch thickness requirement while bending around the 17-foot radius of curvature.

Waterproof rigid insulation and a metal roof complete the structure.   The arch design—one of the largest wood moment frames in the world—has a 1-hour fire-resistive rating and follows the “Special Requirements for Seismic Design of Structural Glued Laminated Timber Arch Members and Their Connections in Three-Hinged Arch Systems” from the 2009 National Earthquake Hazards Reduction Program provisions.

The provisions are intended to produce ductility in the arch systems by allowing the steel connections to yield plastically during a seismic event and prevent glulam members from failing in a brittle fashion.   At the south end of the structure, the roof system cantilevers over the last glulam arch, supporting the curved fascia and creating a covered outdoor gathering space.   The decision to use glulam beams wasn’t purely aesthetic, as it also was one of several features that allowed some of the cost savings necessary to meet a tight budget, says Alan Grant, co-director of Grant Price Architects in Los Angeles.