The Painstaking Battle to Build Miami’s New Signature Bridge Arches
✕ In early August, the Florida Dept. of Transportation quietly extended—for the second time in two years—the expected completion date for the now $866-million Miami Signature Bridge project to 2029. The schedule is now five years past the original 2024 target that the Archer Western-de Moya Joint Venture was aiming for in 2019, when it started construction on the one-of-a-kind, six-arch bridge and surrounding interstate highway reconstruction project. The project team has found that erecting the structure is a singular construction challenge. Unlike more standard precast segmental bridges, the vast majority of the arches’ 345 precast segments are so different from each other that it was next to impossible for precaster Rizzani de Eccher to standardize their construction. “This is the most complex design-build segmental bridge, honestly, in the world,” says Riccardo Castracani, business development director with the firm. “We’ve never encountered something of this magnitude,” he adds, referencing his firm’s global experience. “As complex as it looks from afar, you can multiply that by ten” when scrutinized closely. A view of Arch 5 as Archer Western-de Moya Joint Venture nears final erection in August.Photo courtesy Florida Dept. of Transportation For the overall project, and especially the Signature Bridge, Oscar Gonzalez, senior community outreach specialist for FDOT, notes that the team makes extensive efforts to keep the community apprised of the project’s progress on current and future activities via its project website and weekly emails to roughly 4,000 subscribers, says Gonzales. Monthly stakeholder meetings, open to the public, attract representatives of local venues—such as the nearby performing arts center—and elected officials, he adds. With three of the bridge’s six arches now erected in the heart of Miami, the complex design remains in the spotlight for the builders. Architect Donald MacDonald drew inspiration from the Magic Fountain of Montjuïc in Barcelona, SpainPhoto courtesy Getty Images Some additional materials quantities help illustrate the bridge’s broader scope: 288,646 cu yd of cast-in-place concrete; 95.1 million lb of rebar; 10.9 million lb of post-tensioning; 1,187 square piles; more than 583,000 cu yd of earthwork; and 136 stay cables. Building More Than a Bridge In addition to the bridge, the Archer Western-de Moya Group joint venture is also reconstructing portions of Interstate 395 (left), and segments of Interstate 95 (right).Photos courtesy Florida Dept. of Transportation In addition to the bridge, the overall I-395/SR 836/I-95 Design-Build project will reconstruct 1.4 miles of I-395, from the SR 836/I-95/I-395 Midtown Interchange to the MacArthur Causeway, expanding capacity on I-395 via three through lanes in each direction and providing separate connector ramps for traffic to and from I-95. The project will also modernize the SR 836 corridor from NW 17 Avenue to the Midtown Interchange by double-decking SR 836, providing a direct connection to the MacArthur Causeway. This structure will begin east of NW 17 Avenue, rising above and along the center of SR 836, then ending at I-395, east of the I-95 interchange, according to FDOT. The direct connection to the MacArthur Causeway will be free of local entry and exit traffic, with the existing SR 836 roadway and bridges serving as a collector-distributor system enabling drivers to enter and exit from the local roads and I-95. According to FDOT, this system will reduce existing weaving movements, enhancing safety. On the nearby I 95, from NW 8 Street to NW 29 Street, crews are replacing concrete pavement for the north- and southbound travel lanes, and adding an auxiliary lane along northbound I-95 from north of NW 17 Street to NW 29 Street to handle additional traffic from the eastbound SR 836 ramp to northbound I-95. Additionally, the City of Miami has plans to build a mile-long I-395 Underdeck and Heritage Trail, a public landscape “that weaves below the elevated I-395 roadway, creating a 33-acre urban open space and streetscapes that will reunite the urban fabric of Overtown, a historically Black neighborhood that was disconnected during highway construction in the 1960s,” according to the city. The City of Miami had secured a $60-million U.S. Dept. of Transportation grant for the estimated $82.7-million project, but the Trump administration in August rescinded that funding. While calling the loss a significant setback, Miami city officials told media that the city remains committed to building the project. Designing, Engineering ‘The Fountain’ The six-arch bridge structure, named The Fountain, will span 1,025 ft, with the tallest arch, Arch 5, rising up 325 ft, with a width of 650 ft. The roadway will be supported by twin cast-in-place box girders suspended from each arch. HDR, the engineer of record for the bridge and the I-395 work, describes the bridge project on its website as showcasing “the essence of Miami as the center for the arts, with this structure as its nexus,” adding that it “is inspired by Miami’s world status as the center of the Americas, and the fountain-like arches are symbolic of Miami as a place where people from all backgrounds come together and live as a community.” Visualization illustrates the positioning of all six arches and the west- and eastbound superstructures; rendering shows layout of segmental bridges and typical roadway segments.Bridge Rendering courtesy HDR; Bottom Image courtesy FDOT The precise vision for the centerpiece arches came from the titular principal of San Francisco-based Donald MacDonald Architects LLC, who told ENR he viewed the assignment as “a wonderful opportunity to do something … that needed to be done.” MacDonald—who credits HDR for the two parties’ “close working relationship” during the design phase—says he drew particular inspiration from two disparate elements: the logo of the former Miami-based Pan American Airways, and the Magic Fountain of Montjuïc in Barcelona, Spain. “I used to fly Pan Am a lot, and they had logos that had these arches coming out from South America and North America and ending up in Miami,” he says. “That started me thinking. And then I wanted to get something that was the center for a city, and I found that Magic Fountain in Barcelona [had] these huge fountains in the middle of
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