hotels_westin_frontThe Westin Westminster, Denver, Colorado, is a full-service high-rise hotel located in the center of the city’s promenade and surrounded by shops, theaters, and restaurants. The hotel features mountain and park views and overlooks the Westminster Promenade Lake. The 369-room, 14-story, 250,000-square-foot concrete hotel tower rises to a height of 150 feet over the single story, 50,000-square-foot steel-framed conference center. The total building floor area is over 300,000 square feet.

The concrete hotel tower forms the core of the building. The typical floor slab is a 7½-inch post-tensioned flat slab supported on rectangular concrete columns. The fourteenth floor houses the hotel’s mechanical equipment. The slab thickness here was increased to 8½ inches to accommodate the increased loading requirements, while allowing the rectangular columns to maintain a slimmer profile.

The perimeter of the concrete hotel tower interfaces with the roof of the steel-framed conference center and lobby areas at the second floor level. The second floor supports an indoor swimming pool and a health club. A post-tensioned slab and beam system frames the swimming pool. An outdoor “sunset deck,” which includes amenities such as a hot tub and fireplace, is also located on top of the second floor. In order to accommodate the required architectural floor layout at the building’s main lobby, a 66-inch deep post-tensioned transfer beam was designed at the second level to support a column loaded by the twelve floors above the second floor as well as the roof.

The lateral system is comprised of concrete shear walls of varying thickness. A structurally efficient design was achieved by varying the design concrete strength of the columns and shear walls from a maximum of 6,000 psi at the bottom of the structure to a minimum of 4,000 psi at the top. Dowel bar form-savers were utilized in the slab at the south end of the building to accommodate potential future expansion.

The cast-in-place flat slab concrete floor structure was determined to be the optimal system to accommodate the architectural programming and hotel room floor plan layout. In addition, this system allowed for a shallow floor to floor height (9 feet typical) while providing excellent vibration characteristics. This project received an award of merit from the Rocky Mountain Chapter of the American Concrete Institute in 2000.


Inland Pacific Company, LLC, Hillsboro, Oregon

Hotel Operator:
Westin Hotels & Resorts

Callison Architecture, Seattle, Washington

Structural Engineer:
S. A. Miro, Inc., Denver, Colorado

General Contractor:
Hoffman Construction Company, Portland, Oregon

Concrete Supplier:
Lafarge Construction Materials, Denver, Colorado