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- เผยแพร่เมื่อ 5 ก.ย. 2024
- The National Transportation Safety Board held a virtual board meeting Feb. 21 to determine the probable cause of the collapse of the Forbes Avenue Bridge over Fern Hollow (also referred to as the Fern Hollow Bridge) in Pittsburgh, Pennsylvania.
On Jan. 28, 2022, the 447-foot-long bridge experienced a structural failure and fell approximately 100 feet into the park below. Six vehicles were on or near the bridge when it collapsed and four people sustained injuries. Investigators found corrosion, deterioration, and section loss on all four of the bridge’s legs due to the continual accumulation of water and debris. This finding led the NTSB in May to issue an early safety recommendation urging the Federal Highway Administration to develop a risk-based, data-driven process to identify, prioritize, and perform any incomplete follow-up actions on bridges with uncoated weathering steel components.
During the board meeting, the NTSB’s board voted on the final findings, probable cause, and recommendations. The board also voted on all changes to the draft final report.
Additional information is included in the public docket for the investigation. The docket includes factual information, including reports, interview transcripts, and other investigative materials.
www.ntsb.gov/n...
Corten steel is not recommended for wet locations. The underside of a bridge is not supposed to be wet. The failure to maintain the storm drainage system rotted the steel. The failure to address the obviously rotted steel problem - even after receiving tweets from trail walkers displaying metal parts no longer connected to bridge - took the bridge down.
Yeah ok expert
Only 35 years in the industry, kiddo.@@jasonswift7098
All this fancy-speak, for We never did any maintenance.
Foreign observer here. I do however, document civil structures and have done so for many, many years. I am not a structural engineer. What comes to my mind is a quote from Shakespeare, “Something is rotten in the state of Denmark.” Chose your "Denmark"!
So BIG rust holes was the cause! To the point where crossbracing rusted off. Who would think that!?
I would hope the added regulation and maintenance costs for working in a parkland environment over a waterway was covered…
I'm not a bridge inspector but to my engineering sensibilities any kind of section loss, even 2% sounds unacceptable to me, let alone 100% loss!!!
If the surface coating premise held I would think we would be talking microns, not inches of erosion. Was the metal tested for the right composition? the widespread erosion strikes me as much greater than intended. Was it a particularly difficult climate in that valley or is there a general problem with the design.
And overarching everything, is it too obvious to suggest a material choice with a life expectancy in the hundreds of years? as opposed to the titanic here. Since servicing is inconvenient and municipalities are averse to thinking, why not do it right once and for all? Also maybe a smooth outer surface design like a closed box profile without all the bolts and ledges. A closed minimal outer surface should be easier to defend. The use of high strength steel might also quickly pay for itself in the much lower weight. And if possible maybe even a carbon fiber box profile bridge without any supports to keep it simple. With the right matrix it might last forever with no structural maintenance, only drive surface. Maybe something more high tech than asphalt if that doesn't mesh well with a rigid structure.
AKA: Frickin Bridge!
KISS, Keep It Simple Stupid, bridge designs would help in preventing the failure due to poor maintenance.
Bridges that require a component level FEM analysis to Id critical members should not be used. We are not designing airplanes.
On Fern Hollow I would not be surprised if the design used Hardy-Cross in the design calculate the bending moments in the legs.
The “Swiss cheese” failure model in action - every agency failed their duty: local, state and federal.
🙏🙏🙏
Keep your money at home and repair your home.
built back better
That's not true it's a big ship hits it no matter what the bridge wouldn't have problems maybe not as bad problems. People so lazy nowadays what would you not check the bridges more often because they don't care they just want free money they don't want to work
👏 Promo'SM