NTSB Calls for Examination of Thousands of Bridges Nationwide in Wake of Fern Hollow Bridge Collapse

A Pittsburgh Transit Authority bus that was on the Fern Hollow Bridge in Pittsburgh on Jan. 28, 2022, when it collapsed. (Gene J. Puskar/AP Photo)

Investigators with the National Transportation Safety Board (NTSB) are calling on transportation officials across the nation to examine thousands of bridges following a probe into the January 2022, collapse of the Fern Hollow Bridge in Pittsburgh, Pennsylvania.

In a report published on May 18, NTSB provided an update on its investigation into the collapse of the bridge, which injured multiple people and damaged numerous vehicles.

Officials said that they have conducted 3-dimensional (3D) scans of select portions of the bridge’s superstructure, and performed mechanical and metallurgical testing of bridge components that were collected after it collapsed.

Additionally, investigators have conducted interviews and examined bridges that have similar construction or material features to Fern Hollow while also collecting and reviewing “a wide range of documentation from local, state, and federal sources,” they said.

Investigators said that multiple other bridges across the state have similar design elements to those seen in the Fern Hollow bridge.

“NTSB investigators, with FHWA (Federal Highway Administration) engineers, conducted limited inspections of 10 steel frame bridges located across the Commonwealth of Pennsylvania,” they wrote. “These bridges had design elements or aspects similar to the K-frame design and uncoated weathering steel construction of the Fern Hollow Bridge.”

They noted that drainage issues on the Fern Hollow bridge, including drains blocked by debris, dirt, and plant material, were discovered in inspection reports.

Report Finds ‘Corrosion Damage, Deterioration’

“Our examination of the bridge, as well as the inspection reports, found critical structural components on the Fern Hollow Bridge, including portions of the welded steel legs, with extensive corrosion damage, deterioration, and section loss in the areas with debris and improper drainage,” the report said.

“The NTSB concludes that the legs of the Fern Hollow Bridge experienced significant deterioration and section loss that were documented in inspection reports,” officials wrote. “The deterioration and section loss resulted from the continual accumulation of water and debris, which prevented the development of the protective patina that would resist such corrosion on uncoated weathering steel.”

More than 10,000 bridges in the United States have been built using uncoated weathering steel, according to NTSB, although it is unclear how many of the bridges are impacted by the corrosion issue.

The NTSB said in its report that it is critical that bridge owners nationwide “ensure that follow-up actions addressing the accumulation of water and debris on bridges with weathering steel components have been completed” due to the potential for corrosion and deterioration.

It noted that while the FHWA does not have the authority to require that inspection-identified maintenance is performed, it can require states and other entities to ensure that their bridges have “accurate capacity ratings and are safe for the traveling public.”

“Proper maintenance is critical to bridge safety,” the report concluded.

FHWA said it will review the NTSB recommendations and work with owners of bridges across the country to review inspection reports and determine what needs to be done to address the issue, the Associated Press reports.

Fern Hollow Bridge Collapse

Elsewhere, Pennsylvania Department of Transportation spokeswoman Alexis Campbell said the agency is reviewing the NTSB report and will continue cooperating with the probe into the collapse of Fern Hollow Bridge.

“Safe, reliable infrastructure is a top priority of the [Gov. Josh] Shapiro administration, and we are committed to ensuring Pennsylvanians and all motorists can travel across the Commonwealth safely,” Campbell told The Associated Press. “To that end, PennDOT remains proactive in its review, analysis, and maintenance of its bridges.”

Fern Hollow Bridge, which opened in 1973, was 447 feet long and was comprised of four lanes, according to the American Society of Civil Engineers (ASCE).

It collapsed on Jan. 28, 2022, sending several vehicles and a Port Authority bus plunging 100 feet into a ravine below.

Ten people were injured in the collapse, four of whom were taken to hospital, according to CBS. However, none of those involved in the incident sustained serious or delay injuries.

The bridge was rebuilt and reopened within 11 months after its design and construction were fast-tracked.

The latest report from NTSB follows a 2021 Report Card for America’s Infrastructure which found that 46,154, or 7.5 percent of the nation’s more than 617,000 bridges are considered “structurally deficient,” meaning they are in “poor” condition.

According to that report, more than 178 million trips are taken across those structurally deficient bridges every day.