PROJECT OF THE YEAR: HIGH-RISE
Owner: Ameristar Casinos Inc.
Masonry Contractor: Heitcamp Masonry Inc.
Architect: PGAV Architects
General Contractor: Walton Construction Co.
Structural Engineer: Walter P. Moore
Everything about this project is big, from the exterior elevation that towers 26 stories (300 ft) above the ground, a 300 x 100 ft footprint, and the army of tradesmen which included 25 Bricklayers and 18 Mason Tenders two shifts per day. These two shifts worked 10 hour days, seven days a week for four months at the peak of construction.
Even the performance mock up was big. It was two stories tall and 40 ft long with a complete window system. The new $265 million facility in St. Charles Missouri includes a 400 room all-suite luxury hotel, a 7,000 sq ft full-service spa and indoor/ourdoor pool area with landscaped grounds and waterfalls, as well as a nine-story parking garage.
The scope of work included: 600,000 utility brick, 65,000 sq ft of glass fiber reinforced concrete (GFRC), 15,000 sq ft of architectural precast, and 150,000 concrete masonry units. All of the masonry components were put in place within a 16 month period.
Heitkamp worked with their Hydro Mobile scaffolding distributor to engineer the scaffolding system. The resulting combination included 15 Hydro Mobile units arranged so that there was a 60 ft span of scaffolding platform between the towers. In addition, a 9 gauge metal decking was erected overhead to protect the men from debris and netting was hung underneath to protect workers below.
Keeping all the exterior trade contractors running smoothly required hourly coordination between Heitkamp's Superintendent and the General Contractor's Superintendent, although the exterior skin scheduling was the responsibility of the brick contractor.
The carpenters typically worked from swing stage scaffold above the masons, installing their studs, drywall and sheathing. The iron worker worked on top of a metal deck scaffolding one floor above the masons laying brick one floor below. In the beginning, masonry work was proceeding at a pace of one floor in seven days. Heitkamp suggested putting a glazer on a platform beneath the scaffold platform while bricklayers worked above. With that kind of coordination, workers began to turn a floor in four days.
Seismic zone requirements drove the architect to come up with a hybrid design combining high-rise technology with a traditional veneer system. The building exterior had to be able to move one inch in each direction, with all components moving in concert (studs, drywall, glazing, masonry, GFRC, caulking, steel).
This was the first time this kind of design has been executed in the local market. GFRC was specified instead of heavier precast for the building corners, window surrounds, sills, and cornices. In the interest of efficiency, Heitkamp's masons used welding and mechanical connections to set the GFRC. This normally would have been done by other trades.
The exterior skin design is comprised of a horizontal relief angle at each floor line, with an extensive flashing system that includes 40 mil self adhering flashing that is caulked to the relief angle and attached in the cavity with a stainless steel termination bar. On the exterior, it is finished with a stainless steel drip edge. A dedicated flashing crew of bricklayers installed the flashing ahead of the rest of the crew.
The vertical expansion also includes an expansion joint at every building corner, separating the GFRC and the brick, two in. on one side and three-quarter in. on the other. Thanks to this hybrid design, the building will be able to move and ride out a seismic event.
The interior features high-quality finishes including curved, dimensional limestone cladding. The engineering of the stone anchorage was the responsibility of the masonry contractor. The walls are 16 ft tall, and the top panel is 8 in. from the face of the sheathing. They are also on a radius, with no 90 degree corners. The owner insisted on monolithic stone corners throughout the interior.
In addition to the hotel and parking garage, Heitkamp completed extensive stone work in a "streetscape" entry area connected to an existing casino complex.