Two bridges over the Atlantic Intracoastal Waterway (ICWW) and the Lake Worth Lagoon connect SR 80 (Southern Boulevard) in the City of West Palm Beach to the Town of Palm Beach in Palm Beach County. The main bridge is a movable or bascule bridge which currently provides 10 feet of vertical clearance and 80 feet of horizontal clearance. The second bridge, referred to as the Tide Relief Bridge, is a fixed-span bridge over a narrow section of open water along the eastern shore of the lagoon. SR 80 is also a designated emergency evacuation route from SR A1A on the barrier island to I-95 on the mainland.
Both bridges were constructed in 1950 and because of their long exposure to an extremely aggressive environment, corrosion of the reinforcing steel have led to a premature deterioration of the bridges. To slow the process of corrosion, pile jackets were first installed in 1985 and replaced after ten years in 1995. Bridges are assigned a sufficiency rating based on their overall condition; and bridges with a sufficiency rating of less than 50 are generally eligible for replacement. The movable bridge has a sufficiency rating of 50.3; the Tide Relief Bridge has a sufficiency rating of 36.3.
In addition to the structural integrity of the bridge, features on the bridge that may affect safety such as lane widths, sidewalk widths and lateral clearances between roadway and sidewalks, are considered when determining whether a bridge is functionally obsolete or not. The existing sidewalks on either bridge are only 3.5 feet wide, instead of a minimum 6 feet under current standards. In addition, the US Coast Guard establishes requirements for vertical and horizontal clearances for bridges that cross the ICWW. The existing bascule bridge clearances are less than these requirements.
Planning, Design and ConstructionA Project Development and Environment (PD&E) Study was initiated in November 2006 and completed in April 2009. Final Design of Alternative 5 is currently under way and should be completed by late 2015. Construction is estimated to take approximately 36 months.
The Florida Department of Transportation will replace the SR 80/Southern Blvd. Bridges over the Intracoastal Waterway and Lake Worth Lagoon between West Palm Beach and Palm Beach. The bridges were built in 1950 and are both functionally obsolete and structurally deficient. The new bridges will each carry one lane of traffic in each direction, have 6-foot-wide sidewalks in each direction, and 10-foot-wide paved shoulders which will include 7-foot-wide bike lanes. The new bridge over the Intracoastal Waterway will be a drawbridge with a vertical clearance of 21 feetusing a post-tensioned, reinforced concrete flat slab superstructure. The new bridge over Lake Worth Lagoon will be a low level, fixed bridge similar to the existing bridge with a conventionally reinforced concrete flat slab superstructure. The project also includes reconstruction and paving of the roadway approaches and causeway.
The PD&E study considered the potential social, cultural and physical impacts of the preferred bridge alternatives. The project corridor traverses environmentally sensitive areas, including Bingham Island. The study determined that there would be no adverse effects to nearby historic sites.
Federal and state funding is allocated for future Phases of the project, including Design and Construction. Construction costs are estimated at $91,000,000.
The project is currently under Final Design, with completion of this phase estimated for late 2015. The construction is scheduled to begin in late Summer 2016.