When the hospital added a three-story, 66,000-square-foot expansion to its main hospital, the designers envisioned an attractive link to its new addition.
Creating a high impact, yet contextual transition between the two brick structures was vital to the overall design, said Robert Meyer, project architect for Pratt Design Studio.
Because the connector, a glass-enclosed elliptical structure, would be adjacent to the hospital’s main entry and used as public waiting and circulation, Meyer said “it is an important element to how the building functions.”
Its prominence, combined with its curved glass design and south-facing orientation, required an aesthetically pleasing, yet functional buffer to reduce the heat and mechanical load created by the solar influence on the glass. “We wanted a simple but strong modern statement to accentuate the building,” said Meyer.
The architect’s solution was to design a dramatic and contemporary sunscreen created with 0.125-gauge aluminum perforated metal panels with 1/2-inch holes in a 1.9-inch straight row pattern with a solid metal border from McNICHOLS Co.
The curved sunscreen covers a 20- by 30-foot section of the glass area and is comprised of 112 anodized perforated aluminum panels, each measuring 12 inches by 5 1/2 feet. The structure is built on a 40-degree curve that matches the radius of the glass.
Four-inch horizontal gaps separate the panels, which are embellished with three horizontal aluminum bands that transition to horizontal sunshades that accentuate the curve of the connector. The same louvered sunshades are also used at the windows on the south façade of the new building.
The panels are secured to intricately designed vertical aluminum channels by stainless-steel screws that are placed in decoratively strategic spots. The channels were buttressed and bolted to the building’s structural columns, while at the bases are lights that illuminate the metal after dark.
“The perforation limits the direct sunlight into the space, while still providing visual access to the exterior,” Meyer said, while “the curves and slats add a nice level of detail at night.”
Industrial Sheet Metal Erectors Inc. worked in association with Image Building Products and Tarlton Corp., to create a custom sunscreen with this level of detail. Together with McNICHOLS’ design team and CAD operator, the team laid out the panels on the aluminum channel grid. “There were a lot of details to consider, including connecting the different metals,” said Curt Allen, project manager for Industrial Sheet Metal Erectors.
During the six weeks from design to installation, Allen and his fabrication team, using exact field dimensions, devised a system for attaching the aluminum channels to the structural steel to avoid metal contact corrosion.
“We used stainless-steel bolts with a rubber membrane to separate the two metals,” Allen said. “Then we prepared the structural steel members to receive the bolts.”
Due to the size and positioning of the panels along the vertical channels, the perforated metal needed no bending to create the curve, Allen said.
Between the glass curve and the sunscreen a catwalk was built using structural plates secured to the channels, creating a 3-foot access for cleaning and maintenance of the glass located behind the metal screen.
Today, the completed expansion is home to new inpatient beds, medical offices and a pharmacy. The 2,400-square-foot multistory glass connector houses public waiting rooms on the second and third floors, with a pedestrian corridor on the first floor. The sunscreen, built for function and aesthetics, has become the memorable image associated with the hospital campus.
“The simplicity of the design belies its intricacy,” Meyer said. “Part of the success of this installation is the attention to detail in which a complex assembly of pieces creates a simple, yet powerful element that relates well with the whole design.”
General contractor: Tarlton Corp., St. Louis
Architect: Pratt Design Studio, Chicago and St. Louis
Fabricator: Industrial Sheet Metal Erectors Inc., St. Charles, Mo., in association with Image Building Products, St. Charles
Perforated metal panels: McNICHOLS Co., Tampa, Fla., www.mcnichols.com