The City of Jacksonville, Florida has the largest urban park system in the US. Enhancing its dynamic network of outdoor community spaces, the city is adding numerous docks along the St. Johns River for visiting boaters and water taxis. The new Post Street location in the historic Riverside neighborhood presented several engineering challenges that were easily overcome when the city chose a stateof- the-art SF Marina floating concrete dock array.
The Post Street boat landing site not only contends with a fast-moving river current, but also strong southerly wave action. Coupled with the location being directly adjacent to underground utilities, the dock structure had to be built rock-solid to remain in place if a hurricane were to hit the area. The city specified that it would need to withstand 120-mph winds for two hours with 10-foot storm surges.
Jacksonville-based Hal Jones Contractor, a division of Vecellio & Grogan, Inc., installed the two-part, 95-feet-long by 10-feet-wide SF1230 HD pontoon and three SF1224 32-feet by eight-feet-wide fingers. The sections are joined together using SF Marina’s exceptionally reliable connector system that absorbs torsional tension and heavy loading. The array is designed to accommodate six vessels up to 50 feet in length.
To secure the structure, Hal Jones Contractor drove eight 20-inch steel piles over 40 feet deep into the rocky river bottom. This safeguards against the array moving and damaging the utility lines. Custom guides allow the pontoons to rise and fall smoothly with water level changes.
Engineered with uncompromising strength for heavy commercial use, 1200-series SF Marina floating concrete pontoons have substantial mass and weight. Combined with a wave-dampening design, this makes them exceptionally stable. The dock array connects to the shoreline via a 42-feet-long by four-feet-wide aluminum bridge and 36-feetlong by four-feet-wide hinged gangway. Concrete pontoons for the structure were manufactured in SF Marina’s Norfolk, Virginia facility and trucked to Jacksonville.
The Post Street project was the first SF Marina system installed by Hal Jones Contractor. “We were impressed,” said Greg Tolbert, Hal Jones Contractor project manager. “After two months of use, the docks are performing as planned and we’ll certainly consider SF Marina when looking at future jobs.” SF Marina designs and builds recreational and commercial floating breakwaters and concrete dock pontoons, and related marine structures. Its large international network of offices and manufacturing sites enables delivery anywhere in the world.
For more information, visit www.sfmarinausa.com.
