New inlet bridge to be in use before 2012
Work on two early phases of the construction of the new Indian River Inlet Bridge is revving up, with removal of excess soils from the existing faulty embankments set to begin the first week of April and work begun last week on geotechnical investigations into how the faulty embankments came into being and whether the state has grounds for a claim against their builders.
Delaware Department of Transportation officials issued an update on the project Wednesday, March 5, and addressed a number of the issues and project areas that are moving forward on a timetable to have traffic moving across the bridge no later than December of 2011.
Embankment soils removal is slated to start the first week of April, according to the update, with 600 feet of fill on each side of the embankments to be removed during a project period of 100 days. The state is currently advertising for a contract on the removal project.
The excess soils are to be split between a project to raise the level of the Indian River North parking lot and state borrow pits, where they will be made available for future projects. A report sent to legislators last week confirmed that the soils are not contaminated with arsenic, as had been rumored.
DelDOT has hired O’Connell & Lawrence to investigate the geotechnical work and embankment construction performed on the faulty embankments, hiring them based on criteria that included staffing sufficient to meet “an aggressive schedule” and immediate availability. Officials said the group began work last week, with expectations that it would be concluded by this summer.
“It should not be assumed what the final outcome of this investigation will be,” the update sent out by DelDOT Director of Public Relations Darrel Cole notes.
As for the construction of the bridge itself, a “shortlist” of design-build teams deemed qualified and interested to provide proposals for the project were selected in January. They are Indian River Constructors (a joint venture of Flatiron Constructors Inc. and Kiewit Construction Inc.), PCL Civil Constructors Inc. and Skanska USA Civil Southeast Inc.
The teams will next be submitting concept plans, and technical and price proposals, as outlined in the state’s request for proposals.
“We expect to announce the selected proposal in late spring 2008, and have the bridge available for traffic no later than December 2011,” the update states.
The design-build of the new bridge structure is expected to cost about $150 million. A previous estimate during the prior procurement process was $130 million. DelDOT officials said the additional $20 million was due to inflation and the longer bridge length under the design created after the embankments were determined to be faulty.
Meanwhile, DelDOT officials remained focused on ongoing concerns about the existing bridge’s safety, as it reaches the end of a lifespan estimated by various sources to top out in the years between 2008 and 2015.
“The bridge is safe,” the update emphasizes. “It is the most-monitored bridge in the state, with field surveyors, sensors, yearly dive inspections and yearly surveys of the Inlet bottom by the Army Corps of Engineers.”
As previously noted, the need to replace the bridge is due to severe scouring of the bridge supports by the inlet current over the decades. The velocity of the current in the inlet is considered very high.
The most recent bridge inspection, in August of 2007, showed the deck and superstructure of the bridge rated in fair and satisfactory condition, respectively. The dive inspection of the piers in September 2007 showed they were stable and that rip-rap placed around them as a protective measure in 1989 is intact.
The update warns, however, that future conditions are dependent on many variables that cannot be fully predicted, including future storms.
“While we do not envision these conditions resulting in a sudden collapse of the structure, they could affect its future serviceability,” officials said. “When exactly that might occur cannot be answered.”