High Concrete Group LLC has introduced ThinCastTM, the thinnest precast concrete rainscreen panel available on the market. Designed for use in commercial, institutional, retail, and low- to high-rise construction, this innovation provides architects with the natural beauty and character of concrete in lightweight panels that accomplish their rainscreen design goals.
Location: Chicago, Ill.
Type of Precast: Architectural
Size: 1.2 million square feet (72,390 square feet architectural precast)
With a focus on cancer, gastrointestinal diseases, neuroscience, advanced surgery and high-tech medical imaging, the $470 million University of Chicago Medicine Center for Care and Discovery is at the core of an urban medical school campus. At 1.2 million square feet, it is the largest building on the campus, occupying the north end of two city blocks. Each floor is the size of a typical Wal-mart.
The hospital extends across a campus street over two large sites, a site configuration proposed by the architect that advances the hospital’s goal of maximum efficiency by allowing varying functions to be contiguous to one another and reducing the need for staff to travel between floors. The building was designed to accommodate continually changing medical technology and practices; in particular, the 16-foot (4.88-meter) floor-to-floor height and large 31.5-by-31.5-foot (9.6-by-9.6-meter) structural and planning module allows for enormous flexibility for re-configuring departments and upgrading equipment.
The topmost three floors of the building, located above the Sky Lobby, are enclosed in precast panels—per the original design—whose color and texture recall the limestone facades of the University’s traditional campus buildings. The goal for the building enclosure was to achieve the same flexibility on the exterior as was planned for the interior floor plates, thereby not creating limitations internally via the external skin. The precast elements utilized on the exterior at the upper floors are designed to meet the same performance criteria in terms of energy efficiency as the rest of the building, allowing the University flexibly to change use of the spaces if needed in the future.
The selection of a precast concrete system allowed for aesthetic and structural goals to be achieved within one system. The structural and planning module of the new state-of-the-art hospital measured 31’-6” x 31’-6” in plan and 16 feet floor-to-floor vertically. In order not to break the façade too much, the panel module was set at 31’-6” in width and 9’-0” in height’. Simultaneously, it was the desire of the design team and owner to establish a material relationship with the existing historic campus which is predominantly built in stone. Throughout the construction documents phase, the specifications for the panel were refined so that an energy efficient precast system could be used, helping the design to meet local energy codes and achieve an overall sustainability goal of LEED Silver.
Meeting the budget was a key design challenge. Matching the color and material qualities of the limestone used throughout the University Gothic campus, was an important design goal. Using precast allowed this to be achieved within budget. The inherent versatility and resilience of precast allowed for the creation of a continuous bay window across the patient floors. This extension of space increases the perceived size of the patient room without increasing the floor area.
Another design challenge was the intended profile texture and size of the module. The design team wished to introduce the curved, repetitive profile in order to evoke the texture and depth often present in the gothic revival stonework used throughout the campus. The density and depth of the “tooth” of the pattern and panel length of 31 feet, six inches were challenges addressed in precast fabrication.
The tight site constraints raised concerns regarding panel size. The number of connections, were reduced to improve installation time and meet the challenging project schedule. The design team and High Concrete Group worked collaboratively through all of these hurdles to satisfy the aesthetic criteria while balancing the budgetary criteria of the University. As a key component in the overall exterior wall system, the precast contributes to the energy envelope as well as the sustainable goals of the project. The entire system was assembled to meet the city’s Energy Code and energy efficiency requirements of LEED. In addition, as a regionally supplied material, the precast provides valuable points within the LEED system.
Precast concrete systems provided assistance with aesthetic and structural versatility through the ability to use one system that provided a sound basis for the structure, while complementing and coordinating with the existing campus buildings. The precast itself as a material allows for the formation of complex shapes while retaining key characteristics: thermal, factory controlled environment, speed of assembly, and color matching capabilities. Through careful planning during construction, the precast was erected with minimal disturbance in this tight urban setting, and the use of large building components that are a hallmark of the precast system, allowed the structure to meet a challenging construction schedule. The local energy codes were met by using the energy efficient precast systems, and this in turn allowed the owner to achieve the sustainability that they required for their new structure.