Phased design-build project features storm-hardened infrastructure designed to withstand future hurricanes

The $328 million restoration of the Sanibel Causeway — a key lifeline connecting Sanibel Island to mainland Florida — has reached substantial completion, according to a May 20 announcement by the project team. The milestone marks a major recovery achievement after Hurricane Ian devastated the iconic span in September 2022.

The 12-mile causeway, originally opened in 1963, traverses San Carlos Bay and comprises three separate two-lane bridge spans, joined by two manmade islands. It serves as the only vehicular route to and from Sanibel and Captiva Islands, making its damage in the Category 4 hurricane especially devastating.

Ian’s 150 mph winds and severe storm surge destroyed large sections of the causeway, severing access to the islands and stranding residents in the aftermath. Two ramps collapsed, and a key segment of the roadway crossing a central island washed away entirely, rendering the span impassable.

In the wake of the storm, emergency crews from Superior Construction rapidly mobilized to restore temporary access to the islands. The firm completed the emergency repairs in just 15 days — an impressive 12 days ahead of schedule — even as the permanent design was still being developed.

Now, a joint venture between Jacksonville-based Superior and Miami-based de Moya Group has completed the full restoration of the storm-damaged 3-mile section of the causeway. This work is part of Florida’s broader initiative to rebuild hurricane-resilient infrastructure along its vulnerable Gulf Coast.

The Florida Department of Transportation utilized a phased design-build contract for the project — the first of its kind for the agency. “The Superior-de Moya team had to navigate complex logistics while maintaining two lanes open for traffic flow throughout construction,” the release stated.

To ensure uninterrupted access during the restoration, the joint venture coordinated a massive, multi-crew effort. At peak construction, up to 26 teams were working concurrently, including:

• Three crews driving piles into the bay floor,
• Four teams focused on earthwork operations,
• Two crews handling storm drainage infrastructure,
• Six squads assigned to rebar tying,
• Eight for placing concrete,
• And three working on asphalt paving.

The newly rebuilt causeway incorporates several advanced engineering features aimed at enhancing durability and storm resilience, according to the release. These include:

• Steel sheet pile wall systems: Nearly 750,000 square feet (weighing 26.2 million pounds) of steel, including king pile systems with lengths ranging from 20 to 70 feet.
• Concrete caps: Totaling about 19,750 linear feet for reinforcement and protection.
• Armor stone: 127,996 tons placed strategically to guard against wave impact.
• Elevated seawalls: Raised from previous levels to a height of 5 to 8 feet to counter future storm surges.
• Stormwater drainage systems: Installed throughout to manage runoff and reduce flood risk.
• Asphalt pavement: 19,500 tons laid for the roadway surface.
• Scour prevention system: Utilizing 25,225 square yards of gabion marine mattress and 79,000 tons of coastal riprap and bedding stone to prevent erosion beneath the structure.
• Concrete barriers: 6,900 linear feet of permanent roadside barriers installed for safety.
• Architectural elements: 25,000 square feet of fractured fin concrete fascia to enhance aesthetics and reduce long-term maintenance.

The effectiveness of these design enhancements was tested even before the project was completed. In 2024, Hurricanes Debby, Helene, and Milton all struck Florida, subjecting the under-construction causeway to further stress. “Completed sections withstood these storms intact,” the release stated, “though unfinished areas experienced washouts.”

The Sanibel Causeway restoration stands as a testament to rapid response, resilient design, and coordinated construction efforts — all critical in an era of increasingly severe climate-driven weather events. Its successful delivery is expected to serve as a model for future hurricane-resilient infrastructure projects along Florida’s coast and beyond.

Originally reported by Zachary Phillips in Construction Dive.