According to the report, investigators did not find any primary fractures in the sections of welded steelgirders that they examined. This area is most susceptible to sustain damage if the bridge suddenly collapses.
Early Jan. 28, the Forbes Avenue bridge collapsed, sending four passenger cars and a city bus down 100 feet (30 m) to the bottom in a ravine created by Fern Hollow Creek.
A fifth vehicle drove off of the east bridge abutment, landing on its roof. The agency stated that 10 people were hurt in the accident. Natural gas lines burst and forced evacuation of nearby houses.
The collapse took place just hours before President Joe Biden visited Pittsburgh, to promote a new $1 trillion infrastructure bill.
According to the NTSB, it is currently extracting bridge components in order to conduct closer studies. The agency may take over a year to complete its final report.
The bridge is 447 feet long (136 meters) and was built in the 1970s. It was subject to an inspection in September. However, it was not severe enough to justify its closure. Since 2014, the bridge has been restricted to a 26-ton (24,000-kilo) weight limit.
Although there were no deaths, several patients required hospital treatment. According to a spokesperson for UPMC, all were released by Monday.
According to the state highway department, $25.3 million in National Highway Performance Program funds has been allocated for its reconstruction.
