Repairs bring new energy to Dinner Key Marina

by Cat Olnick
October marks one year since the reopening of Dinner Key Marina and its restoration to original operating capacity since suffering disastrous hurricane damage in 2017. Located in the Coconut Grove neighbourhood of Miami, Florida, Dinner Key Marina is the largest wet slip facility on the eastern United States, and Florida’s largest marina with 587-slips.

Hurricane Irma was an enormously powerful storm that caused extensive destruction throughout Florida and parts of the Caribbean. When it made landfall in the USA on 10th September, the wind speed, storm surge and wave impacts caused considerable damage to all of the marina’s nine piers. Vessels from the mooring field and anchorage outside the marina chaffed through and snapped mooring lines under the extreme forces resulting in vessels crashing into the marina. The damage was devastating, impacting 60% of the dockage.
After the completion of planning and permitting work in 2019 led by Moffatt & Nichol, the City began working with the Design-Build (D-B) team to repair the damaged marina and make significant upgrades to the facility. The D-B team was led by Kearns Construction Company and included Cummins Cederberg as the lead marine engineer overseeing the engineering design of structures and utilities, as well as supporting the ultimate construction.
A short walk from the heart of Coconut Grove village where you will find retail and entertainment, the marina serves as a destination for South Florida’s tourism economy with overnight and monthly accommodations. Dinner Key Marina is the City of Miami’s flagship municipal marina, generating valuable revenue. This restoration project included repairing or replacing structural elements for nine piers totaling over 7,200ft (2,190m) in length and restoring full utility services along with system upgrades. Remaining operational during construction was a challenge the D-B team had to face.
Construction phasing
The ability to keep the marina operational was a crucial element of the timeline. Cummins Cederberg worked closely with the Kearns Construction team to sequence the approach and minimise operating disruptions to the marina.
“The project phasing was really a fluid challenge for the project team to work through and coordinate during the entire construction operation,” says Kearns Construction team lead, Brock Sullivan. “Not only did our D-B team have to physically divide the work areas and staging locations, but we worked with the existing upland utilities to ensure service was uninterrupted for active slip users and dockmaster staff.”
Concrete and finger pier repairs
The core of the structural work consisted of replacing the concrete access piers with a more slender profile consisting of two pre-cast beams laid parallel. This improved section provides more robust resistance to future wave impacts and allows easier access to utilities if future repairs are needed. Cost-efficient concrete repairs were performed to other existing walkway spans, pile caps and select piles in lieu of replacement.
As part of the D-B team’s efforts during pre-construction and active construction operations, opportunities were identified to optimise the construction scope and project budget. Cummins Cederberg and Kearns Construction performed multiple walkthroughs with the City to identify components that could be salvaged by means of repair, allowing funds to be reallocated to other improvements, such as replacing mooring piles or dock piles.
Storm damage repair and mitigation
The D-B team, in collaboration with the City, made the strategic decision to raise all the finger piers during the reconstruction to not only reduce future storm surge impacts but resist increasing seasonal water levels. Subsequently, at the end of construction, the 2021 ‘king tides’ provided record high water levels. The recently renovated piers experienced no flooding, while the existing docks in place during renovation were under water.
The original scope for the timber dock piles included a mixed approach of replacing all framing and decking in certain areas, while other locations called to only replace select framing and dock piles. By performing design level inspections prior to and during construction, the team found more dock piles could be salvaged than in the original plans.
“There’s another layer when seeing the project in real time versus on paper,” states Cummins Cederberg senior project manager, Rasheed Muslimani. “By performing continual inspections, we found more opportunities to optimise the budget for the City and in this situation some dock piles didn’t need to be replaced, making it possible for all docks to receive new framing and decking.”
The D-B team’s optimised dock improvement scope provided new framing and decking for all timber docks – creating a consistent look, stability and access.
Upgraded utilities
Given most of the utility fixtures or supply feeds sustained damage from the storm, the scope included full overwater replacement of all utility systems including domestic water, fire protection, wastewater, electrical and low voltage. With MEP (Mechanical, Electrical and Plumbing) design led by Basulto & Associates and fire suppression design led by REDI Engineering, the team overcame many constructability challenges to address re-using existing upland utility feeds, adapting the design to meet current code requirements and maintaining service in phases.
A significant milestone was the successful acquisition of a City of Miami code variance to design and install seven submersible electrical panels to protect the electrical system from future flooding during a hurricane event without having to position them 11 feet (3.3m) above the existing ground surface. The variance required not only a state-level review from the Florida Building Code Board, but also created a new operating policy for the Dinner Key dock master operations team.
Wi-Fi and security
New utility components were installed to provide a state-of-the-art user experience for both the marina staff and slip users. New security cameras were installed throughout the piers, along with Wi-Fi towers, and remote pedestal monitoring to track water and power consumption.
Safety and access
One of the functionality improvements incorporated by the D-B team was to replace the pier walkway surface with a fibre-mesh grating with a mid-span support beam instead of the previous pultruded glass fibre grating. This robust system provides greater stiffness under foot and support for golf carts and other operational equipment, as well as increased sunlight transmission through the pier to promote the health of underlying marine resources.
On Wednesday 20th October 2021, the City of Miami celebrated the completion of this comprehensive repair and upgrade project to the Dinner Key Marina, and it remains fully operational one year later. Funding for the marina repairs came through the Florida Inland Navigation District (FIND), the Federal Emergency Management Agency (FEMA), and revenues generated by the marina and other City funds.
Today, Cummins Cederberg continues work with the City of Miami to protect this $22.5-million investment by enhancing the protective spoil islands surrounding the marina. These enhancements will include a mix of hard and soft protection measures, such as rock breakwaters and nature-based enhancements as well as increased recreational opportunities to support the community friendly atmosphere prevalent in the region of Dinner Key Marina.
Cat Olnick is marketing manager for Cummins Cederberg, a professional engineering firm working exclusively in the coastal and marine environment. Its team of coastal and marine engineers, scientists, and regulatory experts, specialise in marina design, coastal dynamics, biological monitoring and environmental permitting.
www.cumminscederberg.com