Pre-construction begins on Inlet Bridge
Gov. Ruth Ann Minner, Delaware Department of Transportation (DelDOT) Secretary Carolann Wicks, state and local officials, residents and others were on hand at a Sept. 17 event to unveil the design for a new bridge over the Indian River Inlet and present the selected design/build team — Skanska USA Civil Southeast — to the public.
“This is a vital project for the residents of Sussex County and visitors to our beach resorts,” Minner said. “I look forward to driving over this beautiful bridge and offer my thanks and appreciation in advance to the Delaware Department of Transportation and Skanska for the hard work that will be necessary to bring this project to completion.”
Skanska has already begun some pre-construction activities in the area. Heavy construction is set to begin in early 2009. The bridge is scheduled to be open to traffic by the summer of 2011.
Skanska Southeast was awarded the $150 million design-build project and signed a contract in August. Of the three proposals received for the project, Skanska had the lowest price, highest technical score and proposed the quickest completion time.
The new design is dramatic and functional, officials said. It will have four towers with a single plane of cable stays on each side of the bridge, a narrow profile over the Inlet and an efficient design, they said. For comparison, Williams V. Roth Jr. Bridge over the Chesapeake & Delaware Canal has two towers and a single plane of cable stays down the center of the bridge.
The new bridge will also be 2,600 feet long, including a 900-foot clear span over the Inlet, with 1,700 feet of bridge over land. All supports will be out of the water, eliminating the deleterious conditions that have occurred on the existing bridge. The new bridge will have a minimum 100-year design life. The foundation consists of 36-inch-square piles to be manufactured by Bayshore Concrete Products, a subsidiary of Skanska Southeast. Skanska had previously used these types of piles on the Escambia Bay I-10 bridges in Florida.
Skanska Southeast has earned a substantial reputation as a builder of some of the most noteworthy construction projects in the Southeastern U.S., officials noted, including the Cooper River Bridge in South Carolina and the Woodrow Wilson Bridge foundations in Maryland.
“The bridge builders have officially arrived,” said Wicks. “We have more than two years of construction work ahead of us. There will be ups and downs, there will be issues. But I expect — just like we have in the past — to take them on, address them and move forward.”
“Skanska Southeast is extremely honored to be selected as the general contractor to build the new Indian River Inlet Bridge,” said Peter MacKenna, Skanska executive vice president. “Skanska Southeast has a proud history of building bridges and highway projects that improve safety and ease congestion. We look forward to being a partner with the Delaware Department of Transportation and the Sussex County community.”
The public will have input into determining some architectural and visual features of the new bridge, including lighting on pylon legs and pedestrian walkways, color of the cable stays, and design on the tops of the pylons.
Once major construction commences, the project area will see significant activity in terms of workers and equipment, officials noted. “The process of building bridges is complex and fascinating, and DelDOT is planning site tours and other educational outreach. More information will be provided on these public opportunities in the months to come.”
The current bridge is the most monitored bridge in the state, and it is safe, officials assured the public last week. Yearly visual inspections are just one of the efforts being made to ensure the existing Indian River Inlet bridge remains stable while a new bridge is built. The last visual inspection was conducted in August.
Additional efforts include:
• Pier sensors: DelDOT worked with the University of Delaware to install pier sensors on the bridge (August 2007).
• Underwater dive inspections: DelDOT performs annual underwater diver inspections. The next inspection is scheduled for this month.
• Bathymetric surveys: DelDOT conducts annual bathymetric surveys. Additional surveys are conducted after severe storm events. In addition, the Army Corps of Engineers has continued to provide DelDOT with their periodic bathymetric surveys. These pictures are posted online on www.irib.deldot.gov.
• Land survey equipment: land survey equipment is used to monitor movement on the existing bridge on a regular basis (monthly).
• Sonar monitoring device: DelDOT is working with the University of Delaware to install sonar devices on the bridge to further monitor the scour progression.
The current bridge will remain in place while the new bridge is built. After construction is complete, the old bridge will be demolished, starting from the top down. DelDOT is currently discussing options for disposal with the Army Corp of Engineers.
Officials noted that the longer bridge length was needed because the approaches settled more and differently than predicted and portions of the embankment material needed to be removed from the site prior to construction of a new Indian River Inlet Bridge. Any delays would have further delayed the start of the bridge replacement construction project, they said.
Approximately 140,000 cubic yards of material consisting of dirt and gravel was removed from the north and south approaches and taken to four sites in Sussex County beginning in April 2008. The material was removed from the area closest to the Inlet to a point approximately 600 feet back from the Inlet on each side.
An outside claims consultant continues to investigate the geotechnical work and embankment construction. The results of this investigation will be revealed in the next several months, they noted.
More bridge facts:
• 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 cable-stayed bridge that is similar in construction that has sections over land and water is the Williams V. Roth Jr. Bridge, formerly known as the Chesapeake & Delaware 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 increase from the existing 35 feet to 45 feet over the navigational portion of the inlet. The bridge lane will remain the same with two 12-foot lanes. Wider shoulders will be used, a 4-foot interior shoulder and a 10-foot exterior shoulder, all in each direction. Additionally, one 12-foot wide sidewalk will be 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.
For additional information on the history of the bridge and project including renderings of the new bridge go to www.irib.deldot.gov. DelDOT is encouraging residents, motorists and others to write to DelDOT Public Relations at firstname.lastname@example.org, or 800 Bay Road, Dover, DE, 19903, or call (302) 760-2080 or (800) 652-5600 with questions or input.