A Beacon on Biscayne Bay

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Nature’s power has reshaped the built environment for centuries through its raw, volatile, and destructive strength. But in the process of building and rebuilding, successive generations of architects and engineers have sought inspiration from the natural environment as they innovate and respond to these challenges. And while hurricanes, floods, and fires present significant risks to human life, individuals continue to seek physical, emotional, and spiritual health from the natural world.

With its fluid, organic form echoing the adjacent waters of Biscayne Bay, the Irma and Norman Braman Comprehensive Cancer Center at Mount Sinai Medical Center in Miami Beach, Florida, is designed to draw from the beauty of its coastal environment while standing resilient in the face of hurricanes, flooding, and damaging wind-borne debris.

Because the number of cancer patients across South Florida is projected to rise by at least 12 percent through the end of the decade, the six-story, 220,000-square-foot Braman Cancer Center is a response to both regional healthcare needs and institutional vision. In partnership with Columbia University, the facility will offer a full range of oncology services—from early detection and prevention to therapy and survivorship—under one roof. The Braman Cancer Center is also a strategic investment in patient experience and staff recruitment, designed to attract world-class physicians and researchers.

Rising 90 feet above the western shores of Miami Beach, the building is intended to be iconic. Its sculpted structure is visible from the Julia Tuttle Causeway, offering a striking silhouette against the Miami skyline. But behind the architectural fluidity lies a robust structural system designed to accommodate cutting-edge oncology services while withstanding the destructive environmental forces that threaten its idyllic location.

Because its location is mere feet from the shoreline in an AE flood zone, the Braman Cancer Center is engineered for resilience. The lateral force-resisting system is comprised of 16-inch-thick concrete shear walls that surround stair and elevator shafts at each end of the building. Designed for an ultimate windspeed of 175 mph, the shear walls limit overall service-level wind deflection to less than one inch at the roof of the structure, corresponding to a lateral drift ratio of approximately H/1000.

The concrete shear walls and gravity columns are supported by mat foundations and grade beams anchored to bedrock by 16-inch-diameter auger-cast piles. Due to the poor subsurface conditions, a 12-inch-thick structural slab-on-ground spans between the pile caps, which are spaced at approximately 32 feet on-center. A blind-side waterproofing membrane extends below the slab and across the pile caps and mats, terminating on the vertical surfaces of the columns and perimeter walls to reduce the risk of groundwater infiltration during flood events.

To further guard against water intrusion, finished grade was increased nearly six feet across the site, raising the finished floor approximately 18 inches above the 500-year flood elevation established by FEMA. A 12-inch-thick reinforced concrete site wall extends several hundred feet around the building, serving both as a retaining wall and a barrier against flood-borne debris. The wall is supported by a continuous 9-foot-wide grade beam spanning between pairs of auger-cast piles anchored into rock. With sweeping curves and a parged concrete finish, the protective barrier extends the fluid architectural vocabulary to the site, elegantly grounding the building to its surrounding landscape.

Reinforced concrete was selected for the Braman Cancer Center in response to both the construction practices prevalent in South Florida and specific oncological program requirements, especially a desire to accommodate the anticipated growth in patient volumes and changing healthcare technology with minimal future alteration. Incorporating graceful sweeps and curved massing, the building’s fluid design further supported the choice of a concrete structure, which has an inherent ability to be sculpted in ways that other materials do not.

With a typical story height of 16 feet, each floor of the five-story building is framed with 12-inch-thick, two-way, mild-reinforced concrete slabs spanning 32 feet between each column to support a wide range of oncology programs while minimizing the overall required structural depth. Where necessary, 4 ¼-inch-deep drop panels are located at isolated columns to reduce deflection or increase punching shear capacity.

The inherent mass and stiffness of the concrete structure is particularly important where stringent vibration criteria (VC) are required to operate highly sensitive medical equipment. The second-floor imaging facility, which houses two MRI suites, called for enhanced stiffness to satisfy VC-C, corresponding to an acceleration limit of 500 μ-in/s (mips). Floor construction at the MRI suites is comprised of a 16-inch-thick slab reinforced with stainless steel bars to prevent electromagnetic interference. Adjacent to the MRI suites, HSS posts located behind the exterior curtain wall provide support for removable glazed panels, facilitating direct crane access for future MRI equipment replacement.

A desire to easily accommodate program changes that might result from advances in cancer care guided the design of the floor structure. While a post-tensioned system could have yielded thinner slabs, this approach would have complicated the ability to add new floor openings for MEP infrastructure. Though post-tensioned slabs would have been thinner, the distributed tendons would have complicated the addition of future openings for MEP infrastructure. The mild-reinforced flat slab that was ultimately constructed can be more easily modified and, while requiring more material, provides the mass and stiffness needed to support a variety of vibration-sensitive surgical and imaging equipment.

The building’s ground floor houses high-radiation treatment spaces, including a high dose rate (HDR) brachytherapy vault and multiple linear accelerator (linac) rooms. The HDR vault features a 12-inch structured slab-on-ground, 23-inch-thick normal weight concrete walls, and a 24-inch cap slab that doubles as the structural floor at the second floor. The linac vaults are even more robust, with walls up to 81 inches thick and cap slabs ranging from 36 to 90 inches. Recessed slabs and mats at the HDR vaults, linacs, and elevator pits are proportioned to resist hydrostatic uplift forces up to 340 psf through their self-weight where they extend into the groundwater table.

Due to their size and unique program requirements, accommodating radiation therapy spaces within a standard planning module or column grid—typically between 28 and 33 feet for healthcare projects—is often impossible. The Braman Cancer Center is no exception, and the thick, normal weight concrete slabs above the vaults serve the dual purpose of both radiation shielding and transfer mats for three columns supporting the four levels above the second floor. One and two-way shear design of the mats and the typical floor slabs conforms to the 2020 Florida Building Code (FBC), which was in effect at the time the building was designed and permitted. While the 2020 FBC incorporates ACI 318-14 Building Code Requirements for Structural Concrete, the standards currently in effect, FBC 2023, reference ACI 318-19, which would have resulted in a lower capacity due to the incorporation of the shape effect factor for shear. Though this challenge could have been overcome through the use of higher strength concrete, supplemental reinforcement, or thicker slabs, the Braman Cancer Center offers an example of how changing regulatory standards can impact design efficiency and cost.

Additional column transfers were required at the southern end of the second and fourth floors, a result of the building’s stepped form and curved plan. Concrete girders measuring 48 inches by 72 inches deep transfer seven columns above the second floor, while an additional eight columns are transferred above the fourth floor. The broad terraces formed by these setbacks soften the building’s scale and provide space for outdoor sculpture courts. To withstand hurricane winds, each sculpture is anchored to ½-inch-thick steel plates embedded into reinforced concrete pedestals that are anchored to the primary structural slab.

Further supporting the rapidly evolving landscape of cancer treatment, additional pile foundations and a mat slab at the ground floor are designed to accommodate a third linac room within the current building. Because cast-in-place concrete construction would likely be impractical for the future vault, these foundations are designed to support the weight of high-density modular shielding walls. At the second floor, a permanent steel rigging platform is concealed behind the parapet wall to facilitate the addition of new equipment for this vault and other areas of the building as program needs change.

Sinuous ribbons of horizontal glazing and precast concrete panels elegantly wrap the building’s continuously curved perimeter, creating a dynamic facade that appears to shift and undulate from every vantage point. To overcome the inherent constructability challenges of forming over 600 distinct panel shapes, the design team employed advanced computational tools, allowing for extensive modularization without sacrificing visual complexity.

A custom algorithm, developed in Grasshopper, superimposed a series of waveforms onto five distinct curve types within Rhinoceros 3D (Rhino), defining a series of 40 unique panel profiles. The algorithm was scripted to ensure each ribbon began and ended with a common panel geometry, creating a closed loop around the perimeter of each floor. Through this approach, the design team maintained optimal panel lengths and weights while minimizing the total number of unique panel shapes required. Using computational design tools allowed some panels to repeat up to 16 times, and all profiles were used at least nine times—the minimum threshold established by Gate Precast to meet the practical constraints of the fabrication process and streamline erection.

Weighing between 10,000 and 22,000 pounds, each precast spandrel panel was manufactured in segments up to 12 feet in length. Gravity support is provided by continuous 48-inch by 30-inch concrete beams around the perimeter of the building. Because the panels extend several feet beyond the slab edge, each anchor point is subjected to large torsional forces generated by the eccentric gravity load as well as by wind pressures of 185 psf acting on the exterior envelope. To resist these forces, each precast panel is anchored to a pair of HSS posts that cantilever vertically from embedded steel plates located at the slab edge within the wall cavity.

While the precast spandrel panels are an essential element for achieving the aesthetic goals of the project, they also serve as a sunshade to the ribbons of glass that provide patients with sweeping views of Biscayne Bay and the Miami skyline. Complementing the inherent resilience of the precast concrete to windborne debris, all glazing elements are designed to meet the Miami-Dade County requirements for High Velocity Hurricane Zones, including impact resistance and wind-driven rain.

A visually striking reinforced concrete entrance canopy defines the front of the building. Rising 20 feet above the ground and spanning 50 feet across the patient drop-off driveway, the canopy is supported at the exterior of the building and by a 41-inch-thick concrete wall that curves both vertically and in plan. Along with standard plan details and sections, the structural documents included 3D illustrations and the trigonometric equations used to establish the complex geometry of the support elements. The wall’s exterior is clad in curved precast panels, each weighing nearly 20 tons, while the interior is parged for a clean, monolithic appearance.

The canopy roof structure comprises 36-inch-deep concrete girders that carry a series of smaller beams. Together, these members support a 6-inch-thick, one-way slab designed to withstand wind uplift forces exceeding 200 psf. An ovular skylight, 26-feet-long and 15-feet-wide, is centered within the canopy roof structure. Each glazing panel is supported by HSS members that span between concrete curbs surrounding the opening. Gracefully curving toward the face of the building, the canopy slab becomes a continuous overhang that cantilevers 12 feet from the face of the curtain wall around the entire second floor.

As cancer care continues to evolve, so too must the environments that support it. The Braman Comprehensive Cancer Center at Mount Sinai Medical Center rises to this challenge by offering an adaptable, resilient, and inspiring place for healing. Its flexible design accommodates a broad spectrum of patient services far beyond traditional clinical spaces while anticipating tomorrow’s changing medical landscape. Most importantly, the Braman Cancer Center demonstrates that all of this can be achieved in a building that strives for the highest levels of both beauty and resiliency. Embracing the allure of its site while standing strong against the forces of nature, the Braman Cancer Center is poised to become a landmark for healing at the gateway to Miami Beach. ■

About the Author

John Roach, SE, PE is a structural engineer in the Buffalo, NY office of CannonDesign. Ron Curtis, PE (retired) is the structural engineer of record.