To make sure they don’t have the same kind of corrosion that was detected on the bridge that collapsed, investigators looking into the collapse of a bridge in Pittsburgh have asked transportation officials nationwide to inspect more than 10,000 additional bridges with comparable construction.
In a report released on Thursday, the National Transportation Safety Board claimed that drainage issues on the collapsed weathering steel bridge allowed the metal legs to corrode over time. Even though inspectors had seen the issue, it was found that Pennsylvania had ignored for years to carry out the necessary upkeep to clean the trash, dirt, and leaves that were the root of the issue.
Every inspection performed since 2005, including one finished just four months before the Fern Hollow Bridge fell on January 28, 2022, found evidence of the rust that led to the steel legs of the Pittsburgh bridge deteriorating and allowing holes to emerge in the structure. The drainage system of the bridge was cleared of debris in 2009, but even after inspectors reported in each report from 2011 to 2021 that the drains had gotten blocked once more, the work wasn’t done again in the following years.
Questions on the NTSB recommendations were not immediately answered by Pennsylvania Department of Transportation officials. In response to the NTSB’s initial findings, they released a notice last autumn that was concentrated on the maintenance problems with these steel bridges.
A bus and four cars were dumped about 100 feet (30 meters) into a ravine by the Pittsburgh bridge span that collapsed last year, hurting numerous people hours before President Joe Biden visited the area to support a significant infrastructure measure. Forbes Avenue crossed the span over Tranquil Trail, Fern Hollow Creek, and Frick Park.
After design and construction were accelerated, a new bridge opened to traffic in December.
According to the NTSB, if these steel-frame bridges are properly maintained, they can last for many years. In contrast, the drainage problems in the Pittsburgh case prevented the steel from acquiring a protective patina that would have slowed the corrosion. Researchers examined ten comparable bridges in Pennsylvania and discovered similar maintenance issues, albeit none were as serious as those with the Fern Hollow Bridge.
Even though the NTSB hasn’t finished looking into the Pittsburgh bridge collapse, it wants to urgently bring these vulnerabilities to the notice of bridge owners despite the fact that it’s unclear how pervasive they are nationwide.
In its study, the NTSB recommended that bridge owners—typically cities and states—clear any “accumulation of water and debris on bridges with weathering steel components.”
The organization requests that the Federal Highway Administration assist owners in locating related issues and completing the necessary bridge safety maintenance.