On Thursday, federal investigators said video from a bus about the collapse of the Pittsburgh Bridge in Pittsburgh this year shows that one end of the structure had already fallen when the deformation joint at the other end broke.
The National Transportation Safety Board has released updated information on the collapse of the Fern Hollow Bridge, saying the video gives them more information on the sequence of events.
So far, there is no evidence of “common flaws” in the “solid types of K-frame superstructure” that form the main structure of the bridge, the report said.
The investigation says all aspects of the disaster are still being considered and that the cause has not yet been determined. Investigators are planning mechanical and chemical testing of material samples, as well as studying plate sizes and weld quality.
A preliminary report, published less than two weeks after the crash on January 28, found that the collapse began in the western part of the structure, and noted that parts of the welded steel beams did not have primary fractures considered “critical to fracture.” The critical section of the fracture in the beam is the part that is most likely to show damage if the bridge suddenly gave way.
When the bridge on Forbes Avenue gave way, he sent a city bus and four cars down about 100 feet into a ravine carved by Fern Hall Creek. Another car drove off the support of the east bridge and fell on its roof.
Although a previous report said a total of 10 passengers were injured, the agency has now concluded that there were nine people in the six cars. Two were seriously injured, two were lightly injured, four were unharmed and the status of one person’s injuries is uncertain, the agency said on Thursday. No one was killed.
The rupture of gas pipelines required the evacuation of nearby homes.
The 447-foot-long bridge, which is about 50 years old, showed some deterioration during an inspection in September, but not enough to demand its closure. Since 2014, the weight of the bridge is 26 tons.
The future of the bridge is the topic of a virtual meeting on Thursday night, which is expected to be attended by city authorities and neighbors.
The Pennsylvania Department of Transportation has said up to $ 25.3 million of the National Road Performance Program will be used to restore the structure. The state agency has published images of the “overall design concept” of the replacement bridge.