Summary

 

Needs Assessment

Two bridges connect SR 80 (Southern Boulevard) in the City of West Palm Beach to the Town of Palm Beach in Palm Beach County over the Atlantic Intracoastal Waterway

(ICWW) and the Lake Worth Lagoon.  The main bridge is a movable or bascule bridge which currently provides 10 feet of vertical clearance and 80 feet of horizontal clearance. U.S. Coast Guard required clearances at this site are 21 feet vertical and 125 feet horizontal for a bascule bridge.  The second and easternmost bridge, referred to as the tidal relief bridge, is a low level fixed bridge that spans a narrow section of open water along the eastern shore of the lagoon.  SR 80 is a designated emergency evacuation route from the barrier island communities to the mainland.

 

Both bridges were constructed in 1950.  Despite continued efforts to repair the existing bridges, engineering studies have determined that the bridge structures are deteriorating and are in need of major repair or replacement.  In addition, some elements of the

bridge are not constructed to current design standards.  For example, the existing sidewalks are only 3.5 feet wide; sidewalks must be a minimum of six 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.

 

The movable bridge has a sufficiency rating of 48.9; the tidal relief bridge has a sufficiency rating of 36.3.  Bridges are assigned a sufficiency rating based on their overall condition.  Deterioration of the bridge and an assessment of the features on the bridge that may affect safety are considered when determining the rating.  Sufficiency ratings range from 0 to 100, where 100 is excellent and 0 is extremely poor.   Bridges with a sufficiency rating of less than 50 are generally eligible for replacement with federal funds.

 

Planning, Design and Construction

The next two phases of this project, design and construction, have been combined into one phase and will be referred to as a “Design Build” project.  To prepare the advertisement for the "Design Build" contract, preliminary plans are currently being prepared by FDOT.  Construction is anticipated to begin in mid 2013 and should be completed by 2016.

 

Project Overview

The Florida Department of Transportation (FDOT) District Four performed a PD&E study to evaluate alternatives to rehabilitate or replace both bridges.  The limits of the PD&E study extended from SR-805 (South Dixie Highway) in the City of West Palm Beach on the mainland  to SR A1A (South Ocean Boulevard) in the Town of Palm Beach on the barrier island.  The length of the project is approximately 1 mile.  Alternative 2 was chosen as

the recommended alternative and LDCA was granted by FHWA on May 12, 2009.

 

The existing bridges provide one 12-foot travel lane in each direction, two feet of buffer between the edge of the driving lane and the face of the sidewalk, and 3.5 foot-wide sidewalks exists on both sides of the bridge.  Based on the traffic analysis of the existing roadway network and the traffic projections made for the year 2032 no additional travel lanes will be proposed for the replacement bridges.  However, widening of the existing bridge will be required to meet current design and safety standards.

 

Finance

Federal and state funding is allocated for future phases of the project, including Design and Construction.    The current construction costs estimate for the Preferred Alternative, which consists of construction of a new 21-foot high movable bridge over the Intracoastal Waterway, and a new fixed bridge over the Lake Worth Lagoon is approximately

67 million dollars.

 

Project Status

A design-build request for proposal package and conceptual plans are currently being developed by FDOT.  The design-build phase of this project is scheduled to start in June 2013.