The troubled bridge on Interstate 495 will not be fully open until after Labor Day. Price price tag for a temporary fix is $20 million.
The southbound lanes of the I-495 bridge on the Christina River in Wilmington, could be open as soon as Labor Day this year, and the northbound lanes would be opened several weeks afterward, DelDOT Secretary Shailen Bhatt stated in a briefing on Tuesday.
“The timeline that we are announcing today is only possible because we have acted quickly to mobilize firms and personnel that have a proven track record of reopening critical transportation infrastructure under deadline pressure,” Bhatt said. “As of today, the people, materials and equipment needed to reopen the I-495 bridge is on its way to Delaware from across the United States.”
Design for the project is being managed by international engineering firm AECOM. Construction will be performed by J.D. Eckman, Inc., Chester, Pa. DelDOT stated that the two firms have a history of successful collaboration of rapidly reopening other bridges on the U.S. interstate highway system, including structures on I-95 in Philadelphia and Wilmington.
The department came under fire from Delaware contractors who said they were not consulted on the project, according to a News Journal story.
The plan to reopen the bridge to traffic calls for the construction of new concrete-filled shafts that will go down to the bedrock beneath the columns that have tilted out of alignment, the department reported. The shafts will create a stable surface above the underlying unstable soil.
The concrete shafts will be tied together with a reinforced concrete grade beam. Temporary jacking towers would be erected on the grade beam to restore the bridge’s superstructure to its original position, and lift the weight off of the existing, rotated piers. Once the bridge has been rendered safe for traffic, permanent new concrete columns will be erected to take the place of the piers.
The first phase of construction to re-open the bridge is estimated to cost $20 million, while the cost of the permanently fixing the structure has not yet been determined, Bhatt said.
A number of options were studied, Bhatt said. “We first looked at just shoring up the existing bridge, but that option was quickly ruled out because of the poor soil conditions. Another idea was to fully reconstruct this section of the bridge. That option would’ve put us at an early 2015 opening, which was not a viable option given the traffic volume the bridge normally carries.”
Bhatt said it became clear that the best way to make the repairs was to bring in the contractor early, so that from day one the firm that will fix the bridge is working side- by-side with firm that designed the structure. “We didn’t want to lose time by designing something on paper that a contractor couldn’t build in the field. Work will proceed 24 hours a day, seven days a week until the bridge is reopened,” he said.Bhatt said, “A lot of the questions we’re receiving right now are about what caused the bridge to tilt, whether it should’ve been closed sooner, and when did DelDOT know about the tilt. I want to be clear that we will do a thorough analysis of agency actions and the causes that led to this situation. We will do so in a transparent manner by sharing our findings publicly. However, the major focus of our efforts as an agency right now is to get this bridge reopened as safely and quickly as possible.”
The bridge was closed Monday after an engineer, a few days earlier, saw that piers were out of alignments.. Dirt dumped near the piers is suspected of being a factor. Following the removal of the dirt, the piers moved a tiny distance toward alignment.
