12-STORY HOTEL ON A TIGHT URBAN SITE; CECO’S STRUCTURAL DESIGN-ASSIST SERVICES AND DRILLED PIER COORDINATION HELPED TO DELIVER THE PROJECT WITHIN BUDGET
The Residence Inn Clayton Hotel in Missouri is a Marriott-branded 12-story upscale hotel that features amenity, ballroom and meeting space, 170 guest rooms, and an outdoor bar overlooking Clayton’s largest and oldest park. The hotel enhances the city’s skyline while providing easy access to downtown offices, restaurants, and nightlife.
Ceco provided the structural concrete frame for this project, which included installing 500 tons of rebar plus 170,000 pounds of post-tensioning tendons and pouring 8,900 cubic yards of concrete. Formwork systems used include Ceco’s in-house Cefco perimeter tables plus HV system for slabs, Gates and Symons forms for columns and Ceco aluminum gang wall forms at stair, elevator, and shear walls. A self-raising platform was used to lift the elevator core wall forms.
Most important, Ceco’s structural design-assist services and drilled pier coordination helped to deliver the project within budget.
Ceco design-assist to the rescue
The hotel building is a post-tensioned (PT) concrete flat slab structural system with concrete stair walls and stairs. However, it was previously designed as a two-story cast-in-place (CIP) podium with a modular/pod structure above. The modular/pod company intended for the project was no longer available to complete the design, and an interim design did not ensure an efficient structure, particularly at the deep foundations.
Ceco teamed with structural engineer SSC and drilled pier foundation subcontractor Drilling Service Co. to propose a 12-story CIP concrete structure with a revised drilled pier layout, providing a structural design within the owner’s budget. The flexibility of the PT slab spans allowed for concrete columns to be sized and located to accommodate both lower-level amenity spaces and upper-level guest rooms. Variable and angled concrete slab edge locations allowed for the desired building geometry and façade connections.
Design and construction challenges
The project sits on a tight urban site with tall existing buildings to the west, north, and east. Due to the limited space around the building footprint, the tower crane had to be erected freestanding, tall enough to clear one adjacent building and not swing over another. SSC designed a deep tower crane foundation to accommodate these requirements as well as future site utilities near grade level in the crane foundation area.
Additionally, a below-grade concrete water detention vault had to be incorporated into the structural design to meet local fire protection code. Both the vault and the deeper tower crane foundation required Drilling Service to design and install temporary earth retention that would protect adjacent street and alley access during construction.
Construction began with drilling 57 piers before constructing the below-grade concrete water detention vault, grade beam foundations, and elevator pits. The slab on grade and concrete structure followed.
To accommodate the lobby, ballroom, and other amenity spaces, the ceiling heights of Levels 1 and 2 are notably taller than typical floors, which required taller shoring for slab formwork and taller column and wall forms. Ceco engineers carefully planned shore and form heights to ensure the same formwork could be used throughout all levels.
Once past Levels 1 and 2, the Ceco team built the structure’s typical floors faster than anticipated to help meet overall schedule expectations.