New Plans for Indian River Inlet Bridge
Indian River Inlet
The Delaware Department of Transportation (DelDOT) has developed a path forward for the construction of a new bridge over the Indian River Inlet.
DelDOT expects that a new Indian River Inlet Bridge (IRIB) contract can be awarded by spring 2008, with construction complete by 2011. The significant change in this process is that the new bridge is proposed to be 2,600 feet long, including 900 feet for the actual clear span over the inlet, with 1,700 feet of the bridge over land. The previous design called for a bridge approximately 1,400 feet long. The piers of the new bridge would remain out of the water.
The additional length is needed because of continuing settlement problems encountered with the recently built approaches for the new bridge.
At a press conference at the Indian River Inlet today DelDOT Secretary Carolann Wicks said, "After careful consideration of all the issues and reviewing our options, it has become clear that regardless of the path forward we chose, there would be increased costs involved. What became the prominent issue then was the timely completion of the bridge. Rebuilding the approaches, or waiting for the fill to properly settle, would have taken much longer and left more to chance than is acceptable for this project. It is therefore in the best interest of the beach area communities to build a longer bridge."
Due to the types of underground soils in this area, settlement was required in advance before the roadway was opened. Projects with such geotechnical issues can be difficult to predict even though estimates are based on soil samples from the site. As of August, approximately 60 percent of the settlement of underground soils had been achieved. DelDOT estimates it could take an additional seven years to achieve the desired 95 percent settlement. As a result, we have the following issues:
* Current settlement of the underground soils has exceeded original predictions. Additional fill would be needed to achieve the correct grade for the approaches to meet the proposed bridge elevation.
* Roadway embankments are shifting and leaning toward the west, and it has been difficult to estimate the magnitude of this problem.
* As result of the weight of the embankments and their unexpected westerly shifting, nearby roads have been impacted, requiring Route 1 pavement repairs and Road 50A reconstruction.
* Bridge construction would be delayed until the problems with the settlement are resolved.
These issues of settlement were expected but not to the degree we are seeing now.
The cost of the new longer bridge is estimated at $150 million. The previous bridge was estimated to cost $130 million. The cost of fixing the approaches would be similar to the cost of building a longer bridge. In addition, the construction of a longer bridge will reduce uncertainties with the approaches and allow the bridge construction to begin sooner.
Before the end of the year, DelDOT expects to begin removing most of the dirt approaches - approximately 600 feet on each side. This process could take approximately four months. DelDOT will explore economical ways of disposing of this material either for use on other roadway projects or other public works initiatives.
A Request for Qualifications (RFQ) from design-build teams will be advertised on October 29, 2007. This will be followed by a Request for Proposals (RFP) from the shortlisted teams.
DelDOT Chief Engineer Bob Taylor said, "Our project team, made up of key personnel from across several divisions within DelDOT, is focused on carrying this procurement process through to conclusion. We look forward to working with a world class design build team to bring our customers a quality replacement bridge."
The first attempt to award a bid for a new bridge was cancelled in October 2005 due to only one bidder expressing serious interest in the project as well as other factors, such as a glut of major infrastructure projects nationwide. This original design (it would have been the first design of its kind in the U.S.) was also much different than the simplified design now proposed.
In the most recent process (April 2007) to award a contract for bridge construction, DelDOT went as far as accepting proposals. However, a subsequent review revealed that the 2006 Bond Bill provisions authorizing this design build project were ambiguous. Such ambiguity rendered it impossible to assess the legality of the process. To avoid protracted litigation, DelDOT set aside the bids in order to work with the General Assembly, state Office of Management and Budget, and the state Department of Justice to clarify the ambiguities in the statutes. That new language was made law in July and allowed DelDOT to move forward with a new design build procurement process.
For the current design build, price is being weighed more than in the previous process but the final award is still not based on the lowest bid. Technical qualifications remain a significant part in the final decision.
The Indian River Inlet Bridge is the most monitored bridge in the state, and our number one bridge priority. The velocity of tidal currents in the inlet is very high and unique. The need to replace the bridge is due to the severe scouring in the Inlet adjacent to the bridge substructure that has occurred over decades. However, the existing bridge is in no immediate danger of failing. The bridge deck is made up of five spans of steel girder beams, each approximately 250 feet long. This is considered a redundant system, meaning that if one span failed, other spans would be able to carry the load allowing the bridge to remain standing. In the department's most recent bridge inspection (September 2007), the deck and superstructure are rated in fair and satisfactory condition. More significantly, our annual (September 2007) dive inspection shows the piers under the water are stable, and that the rip-rap placed in 1989 is intact.
To ensure the existing bridge remains stable while a new bridge is built, the regular inspections will continue, the U.S. Army Corps of Engineers will provide DelDOT with their periodic bathymetric surveys and land survey equipment will continue to be used to monitor the existing bridge on a monthly basis. DelDOT recently worked with the University of Delaware to install sensors on the piers of the bridge. This latest effort will further enhance the department's current bridge monitoring program. These sensors offer the department added confirmation that the bridge piers are stable. Should any change occur, the sensors would provide DelDOT an opportunity to promptly respond.
The public can be assured that if a natural disaster or other event occurs, we will immediately inspect the bridge to ensure it is stable. If it was a danger to travelers, we would not hesitate to close it.
* The current 860-foot bridge was built in 1965, and was widened in 1976.
* Until 1928, the Inlet functioned as a natural inlet, shifting up and down the coast over a 2-mile range. Between 1928 and 1937 the Inlet was kept open by dredging, and in 1938, the U.S. Army Corps of Engineers constructed the jetties.
* The first bridge over the Inlet was a timber bridge constructed in 1934, followed by a concrete and steel movable swing bridge built in 1938. This lasted until 1948 when it was destroyed by ice flow and extreme tides. Another concrete and steel swing bridge built in 1952 lasted until the current bridge was built in 1965.
* Another large Delaware bridge that has sections over land is the Williams V. Roth Jr. Bridge, formerly known as the C&D Canal Bridge. It is 4,650 feet long and features a 750-foot deck surface that crosses the canal.
* Under the new design, the capacity and function of the bridge will not change. The minimum vertical clearance will remain at 45 feet over the navigational portion of the inlet. The bridge width will remain the same (two 12-foot lanes, a four-foot interior shoulder, a 10-foot exterior shoulder in each direction, and one 12-foot wide sidewalk accessed from the east side of the bridge). The reduced embankment limits will result in the elimination of the massive wall surface areas and will provide a more open view between the bay side and ocean side.
More information on the project and the new path forward is available at www.irib.deldot.gov.
DelDOT encourages residents, motorists and others to write to DelDOT Public Relations at email@example.com, or 800 Bay Road, Dover, DE, 19903, or call 302-760-2080 or 800-652-5600.