Worker position a drill along one of the columns on the I-495 bridge Thursday, June 12, 2014. / JENNIFER CORBETT/THE NEWS JOURNAL
WILMINGTON, Del. - Tilting bridge support columns along I-495 continue to inch back to vertical alignment since the removal of soil piles blamed for the roadway's closing at the Christina River, state officials reported Thursday.
Crews closed the 90,000-vehicle-a-day stretch of highway on June 2 after four sets of columns along the bridge's southern approach tipped as much as 4 degrees, causing travel lanes to tip as well. Sensors show the columns have moved 0.26 degrees back toward vertical, or about 6.5 percent.
The Delaware Department of Transportation has tentatively blamed the dangerous movement of the bridge on a contractor's stockpiling of as much as 55,000 tons of soil on land adjacent to the span. Some of the pile crossed onto the state's right of way.
State and city officials have released little about the origins of the material or why the mass managed to go unnoticed, despite a string of Freedom of Information Act requests to agencies that apparently failed to catch the threat, or violations that would have flagged it.
Late Thursday, in response to a series of questions, the Department of Natural Resources and Environmental Control reported that "neither the City of Wilmington nor DNREC's Sediment and Stormwater Program was aware" of soil stockpiles beneath the span.
"It is astounding that no one saw that, or, clearly, people saw it but no one acted on it," said Senate Minority Whip Gregory F. Lavelle, R-Sharpley. "It's a colossal failure."
"I understand that some of the other bridges have stuff under them, vehicles, things like that, because of people taking advantage or getting lazy. But this is like not seeing Godzilla," Lavelle said. He added that the bridge shutdown and traffic snarls are "all you hear about" from constituents.
The piles are clearly visible in aerial photos from 2013, under and alongside the bridge off busy Christiana Avenue. DNREC inspectors have been active in the same area for years attempting to enforce environmental laws at a troubled industrial-scale composting plant nearby.
Keogh Contracting Co. was required to secure a sediment and erosion control permit from the city for a stockpile even a fraction of that size, under authority delegated by DNREC and reviewed by the state every three years. DNREC officials said only that the case is now considered a "potential 'no plan' violation" to be investigated by DNREC.
DelDOT has retained a geotechnical engineering consultant to independently investigate the bridge damage and report on the cause. Officials believe that pressure from the soil pile compressed and distorted soft soils and silt under the area, sending pressure in all directions and bending the deeply driven steel piles supporting the bridge.
Federal Highway Administration officials have approved $2 million in emergency aidfor work to repair the bridge and restore traffic.
DelDOT Secretary Shailen Bhatt announced a $20 million contract for around-the-clock repair on Tuesday designed to restore traffic to southbound lanes by Labor Day. The temporary repair plan is expected to allow the reopening of northbound lanes two to four weeks later, with permanent repairs to follow.
Bhatt has said that his agency is conducting an internal review to determine how officials handled citizen warnings about the threat days and weeks before the shutdown. The adequacy of DelDOT's right-of-way inspection practices also are under review.
The agency last week inspected 29 bridges more than 500 feet long with the potential for stockpiling or storage of materials underneath the spans, within the state's rights-of-way, or close enough to potentially affect the structure's stability.
Materials were found in several cases, but nothing to the extent of the dirt mountain stored along I-495. Under two bridge, inspectors found fill and/or construction equipment stored under the bridge.
"In those two cases, we sent out another team to inspect the substructure units that were near the materials to make sure they were still plumb, and everything was safe there," said Calvin Weber, bridge maintenance engineer for DelDOT. "There was no cause for safety concerns."
Vehicles are regularly parked under some of the bridges, but those won't be relocated, officials said.
"Not only in Delaware but in other places, it's not unusal to park vehicles under bridge decks," Sundstrom said. "The weight of a vehicle, while heavy, is not remotely comparable to the weight of the pile beneath the I-495 bridge."
Crews this week began checking the next set of state-maintained bridges â?? those between 200 and 500 feet in length â?? again with the potential for stockpiling or storage of materials underneath them, Weber said.
The state has also asked the U.S. Army Corps of Engineers to conduct similar checks of their bridges in Delaware, including the Reedy Point Bridge (Del. 9) and Summit Bridge (Del. 896).
DelDOT has said this data will be recorded as part of periodical bridge inspections from now on. The agency is also considering the use of automated monitoring technologies in the future, so that DelDOT engineers would be notified when something is amiss.
Crews at the bridge site continue to work to install ties between the pairs of damaged bridge supports. Materials for the repairs are beginning to arrive, including 4-foot-wide steel casings that will be used to create concrete shafts for the new bridge foundation.
Read the original story: Columns on closed Del. I-495 bridge rebound farther