Development of a Precast Concrete Flat Slab Emulation for the Westin Riverfront Resort

The Westin Riverfront Resort is a totally precast concrete building, which emulates flat-slab post-tensioned construction and demonstrates that a precast alternative could be constructed in winter conditions on a confined site. Approximately 3700 precast pieces using four basic precast components: elevator/stair cores, precast columns with capitals, beam-slabs and rib-slabs, allowed the precast erection to be completed two weeks ahead of schedule. This paper describes the structural concept, component testing, fabrication and construction of the building. The Westin Riverfront Resort is a nine story luxury hotel with 50 500 sq. m of hotel, lobby, parking and auxiliary space. Serving the ski areas of Vail and Beaver Creek, Avon Colorado is located on the western slope of the Rocky Mountains approximately 160 km west of Denver. The overall building project consists of three towers and a plaza/parking area. The plaza/parking structure is three stories. Parking is located below the plaza on the east side of the building while conference rooms are below the plaza to the west and north. In addition to the dissimilarity in building use, Fig. 1 shows the considerable variation in the plan geometry to accommodate the parking and convention facilities. The two mid-rise towers extend three and four stories above the plaza. A high-rise tower is five stories above the plaza giving an overall height of eight stories. In addition to providing a general layout of the structure, the locations of other features described in the paper are identified on the plan. The structure design was a competition between precast concrete, steel and cast-in-place deck and flat-slab twoway post-tensioned construction with a column grid spacing of approximately 9,1 m × 9,1 m on center. All concrete work was completed during the winter months between November 2006 and May 2007. The Vail valley has neither a well established labor pool nor housing for transient construction crews. Cement and ready mix concrete availability and construction during the winter posed possible construction delays. Faced with these constraints, the general contractor requested a precast concrete alternative design for the project. In addition to off-site fabrication, a precast solution eliminated most winter concreting requirements and the shoring and reshoring constraints of cast-in-place construction. The short schedule precluded a structural redesign and resulted in a precast design alternative that not only emulated flat-slab construction but additionally required that the column spacing, structural layout and building perimeter of the original design be maintained. Consequently, optimization of precast elements was not an alternative for the project and precast concrete solutions based on uniform column placement were not applicable to this site.