Why did I-95 collapse in Philadelphia? Drexel University engineer explains possibilities
PHILADELPHIA (CBS) -- A Drexel University engineer and professor believes extreme heat was the main reason behind the Interstate-95 bridge collapse Sunday morning in Northeast Philadelphia.
Amir Farnam joined CBS News Philadelphia on Monday morning as engineers are studying the damage caused to the highway in the hopes of finding ways to prevent such collapse in the future.
Farnam said it appears I-95 is made of steel girders and concrete slabs. He says steel girders are normally susceptible to fire hazards and heat.
"In this case, you do have a fire under the bridge, it could create extreme heat," Farnam said, "and that extreme heat could decrease the strength of the steel and that I believe is the main reason behind this collapse."
Sources say the tanker, carrying gasoline en route to a Northeast Philadelphia gas station, failed to properly navigate an I-95 off-ramp at Cottman Avenue and State Road.
Sources say the truck crashed into a wall, exploded and led to a catastrophic failure of key support systems for an elevated interstate that clocks 160,000 vehicles daily, bringing the roadway crashing to the ground below.
"From what we understand, the tractor-trailer was trying to navigate the curve, lost control of the vehicle, landed on its side and ruptured the tank and ignited the fire," PennDOT secretary Mike Carroll said.
Under normal circumstances, Farnam says building a bridge "takes a few years," but since I-95 is a high-traffic highway, more resources could expedite the process.
"I think that with good resources, we may be able to get it done in a few months," Farnam said. "I hope that it can be done in a few months, but again, this is a very complex structure. I'm hoping that we could allocate enough resources for this incident."
Pennsylvania Gov. Josh Shapiro said Sunday that he plans to issue a disaster declaration and use federal funding to repair I-95.
Shapiro said the commonwealth expects it to "take some number of months"
"We expect it to take that time," Shapiro said Sunday, "and we will have that specific time set forth once the engineers and PennDOT have completed their review."
A preliminary report is expected to be released in the two to three weeks by the NTSB on the investigation of the fire and collapse of I-95.
