Video footage from a transit bus of the Fern Hollow Bridge collapse this year shows one end of the structure had already fallen when an expansion joint at the other end was pulling apart, federal investigators said Thursday.
The National Transportation Safety Board issued an update on the Fern Hollow bridge collapse, saying the video is giving them more information about the sequence of events.
So far there's no evidence of "widespread deficiencies" in the "rigid K-frame superstructure types" that form the bridge's basic structure, the report said.
The investigative update said that all aspects of the disaster are still being looked at and that the cause has yet to be determined. Investigators plan mechanical and chemical testing on material samples and will examine plate dimensions and weld quality.
A preliminary report issued less than two weeks after the Jan. 28 collapse had found the collapse began at the structure's west end and noted there had been no primary fractures in sections of welded steel girders considered "fracture critical."
A fracture critical area in a beam is the part most likely to show damage if the bridge has suddenly given way.
When the Forbes Avenue bridge gave way, it sent a Port Authority bus and four passenger cars down some 100 feet to a ravine carved by Fern Hollow Creek. Another vehicle drove off the east bridge abutment and landed on its roof.
Although the preliminary report had said a total of 10 vehicle occupants had been injured, the agency has now concluded that there were nine people in six vehicles. Two were injured seriously, two had minor injuries, four were not hurt, and the injury status of one person is uncertain, the agency said Thursday. No one was killed.
Natural gas lines ruptured and required the evacuation of nearby homes.
The 447-foot-long bridge, about 50 years old, showed some deterioration during an inspection in September but not enough to require its closure. The bridge has had a 26-ton weight limit since 2014.
On Thursday night community members held a public meeting with city officials to discuss the bridge’s replacement. PennDOT is leading the expedited design and reconstruction effort. When the state agency released preliminary designs in March, members of the city’s Art Commission described it as “very similar to any highway overpass.”
Since then, a number of advocacy groups and neighborhood organizations have signed a resolution to request changes to its design and its function.
Ken Doyno of the Briar Cliff Road Association, and president of the architecture and design firm Rothschild Doyno Collaborative, said he and his neighbors accept that compromises have to be made. However, they feel compelled to advocate for changes and “to put forth a bridge that was a symbol of everything we aspire to, and everything that we need as a community.”
Doyno noted that President Joe Biden’s infrastructure law prioritizes separated biking and walking spaces, better multimodal connections, safer routes to school and equity.
“Of all the places where this needs to happen in our country, that needs to happen in communities that are struggling,” he said, and cited very different household median incomes between Wilkinsburg, the City of Pittsburgh, and Allegheny County. “This is where we need to be spending our money in order to connect our communities.”
The three main changes the coalition would like to see would improve park access and safety through better train connections and traffic calming measures. The most significant request is to build a pedestrian bridge that would be supported by the new structure. The “Park Path Bridge,” as Doyno referred to it, would connect with the play fields and park, as well as provide safer spaces for cyclists and pedestrians alike.
The bridge replacement’s current design envisions a shared-use path for cyclists and pedestrians on its southern side. However, residents worry that cyclists will be traveling at higher speeds as they enter that shared space.
Deputy Mayor Jake Pawlak said Mayor Ed Gainey appreciates residents’ patience with the traffic issues in the area that resulted from the bridge collapse, as well as their advocacy for the vision of their communities. However, he said the project faces some “real limitations.”
In order to fast-track the bridge’s replacement, Pawlak said the city waived the right to a lot of the regular design review and public input processes. It wasn’t an easy decision, but, “the Gainey administration’s first and foremost priority here is the restoration of full public safety services to everyone east of the Fern Hollow Bridge.”
Still, Carolyn Hare of the Briar Cliff Road Association said at the meeting’s end that it’s important not to settle, and urged people to provide input through PennDOT’s website.
“I think that with just a few voices, and a few people being willing to not compromise in this situation, that we can actually end up with the outcome that will make us all proud.”
Officials said construction has begun and will begin to ramp up soon.
