BRIDGE RESCUE: Fire-damaged I-85 bridge in Atlanta reopens

Officials reopened the bridge about a month ahead of schedule, thanks to fast-track reconstruction efforts by the contractor and GDOT staff

Bridge Rescue News Engineering News-Record; Atlanta Journal-Constitution May 15, 2017
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Image source: Georgia Department of Transportation

The Georgia Deptartment of Transportation (GDOT) reopened a collapsed section of I-85 in downtown Atlanta by the evening of Saturday, May 13, officially completing a six-week effort to restore the section of highway that normally carries nearly 250,000 vehicles a day.

 

The southbound lanes on I-85 reopened to traffic Saturday night, while the northbound lanes were put back in use the day before.

 

Contractor C.W. Matthews Construction will earn an estimated $3.1-million early-completion incentive for finishing the work roughly a month ahead of the original schedule.

 

GDOT staff and the contractor accelerated the reconstruction process that began shortly after a March 30 fire in a material storage area caused approximately 700 ft of elevated highway to collapse. Initial assessments projected construction to last at least until mid-June.

 

According to GDOT, the fast-track reconstruction saved time through the use of 24-hour accelerated curing concrete, prefabricated steel cross frames in lieu of cast-in-place concrete diaphragms and reinforcement of 13 supports that survived the fire. Weather was also on the project team’s side, with only one full workday lost due to rain.

 

Other issues proved more challenging, such as designing the prestressed replacement beams to support the curvature of the six deck spans being replaced. Two of the spans are trapezoidal in shape, transitioning from a skewed crossing at a local road back to perpendicular joints, according to an explanation from GDOT Director of Construction Marc Mastronardi.

 

In all, crews used more than 2,100 cu yd of concrete and 505,000 lb of steel to complete the structure. The federal government is expected to pick up 90% of the rebuild contract, currently estimated at $16.6 million. The federal government had already advanced GDOT $10 million in emergency relief funds.

 

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