How the I-95 collapse compares to I-85 collapse in Atlanta six years ago

PHILADELPHIA -- Engineers are busy creating a plan to get the collapsed portion of I-95 in Philadelphia rebuilt as quickly as possible.

Giving people hope is a similar incident in Atlanta six years ago, when crews were able to make repairs in less than two months.

The fiery bridge collapse toppled a portion of I-85 in 2017, shutting the overpass down completely.

Investigators say a homeless man sparked the intense blaze after intentionally setting a chair on fire and subsequently igniting combustible materials stored under the highway.

Engineers say neither collapse was due to infrastructure issues, but a result of extreme heat.

"We design stuff to be reliable and this is odd and unreliable. It's happened in the past. But if you consider bridge fires that happened, compare it to a home fire or building fire, there's way, way, less of those," said Andrew Bechtel, a civil engineering professor at The College of New Jersey.

SEE ALSO: Officials: Driver lost control of tanker before fire, I-95 collapse

Sources tell 6abc Action News that human remains have been found in the wreckage after a tanker truck fire led to the partial collapse of I-95 in Philadelphia over the weekend.

Given the size of the I-95 collapse and damage, Professor Bechtel expects the repairs to take much longer than Atlanta.

"They have to remove everything that's there. Look at what's left -- that's months," said Prof. Bechtel. "Every bridge is essentially custom-made, brought to the site and constructed. And I-95 is a big road that carries heavy traffic."

Dr. Abi Aghayere, a structural engineering expert at Drexel University, says while the 2022 bridge collapse in Pittsburgh took a year to rebuild, this should not take as long.

The Pittsburgh bridge span that fell last year dropped a bus and four cars some 100 feet into a ravine, injuring several people hours before President Joe Biden visited the city to promote a massive infrastructure law.

A new bridge opened to traffic in December after its design and construction were fast-tracked.

"The bridge in Pittsburgh that collapsed in 2022 was rebuilt in one year, this is just a small span. I don't know what the measurement is, but it shouldn't take that long for them to put it back together," Aghayere said.

Crews have been working around the clock, inspecting and then demolishing the damaged stretch of road while engineers are designing its replacement.

Many drivers say avoiding the mess is impossible.

"You don't realize how much that cripples the city, you really, really don't," said Ruth Acker of Bridesburg.

Officials say it could take months to repair both the northbound and southbound lanes that were damaged by the deadly tanker fire.

To speed up the process, Governor Josh Shapiro is asking the feds for more money.

"I think the clear message from us is that any federal resources that are necessary will be made available to ensure that this bridge gets reopened as quickly as possible," said Federal Highway Administrator Shailen Bhatt.

SEE ALSO: Drexel University engineer explains possible cause of I-95 collapse in Philadelphia

As we grapple with the aftermath of the Interstate 95 collapse in Philadelphia, local engineers are dissecting this incident from every angle.

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The Associated Press contributed to this report.