Fern Hollow Bridge

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Fern Hollow Bridge
Fern Hollow Bridge, viewed from the southwest on 7 Jan 2022.jpg
Fern Hollow Bridge viewed through trees, three weeks before collapse (Jan 7, 2022)
Coordinates40°26′22″N 79°54′01″W / 40.43944°N 79.90028°W / 40.43944; -79.90028Coordinates: 40°26′22″N 79°54′01″W / 40.43944°N 79.90028°W / 40.43944; -79.90028
CarriesForbes Avenue Edit this on Wikidata
CrossesFern Hollow Creek, Fern Hollow Edit this on Wikidata
LocaleFrick Park Edit this on Wikidata
Characteristics
Total length447 ft (136 m) Edit this on Wikidata
Clearance below60 ft (18 m) Edit this on Wikidata
History
DesignerRichardson, Gordon & Associates Edit this on Wikidata
Construction cost$1,230,000 Edit this on Wikidata
Inaugurated1 June 1973 Edit this on Wikidata
CollapsedJanuary 28, 2022
ReplacesOld Fern Hollow Bridge Edit this on Wikidata
Location

The Fern Hollow Bridge was a bridge in the East End of Pittsburgh, Pennsylvania that carried Forbes Avenue over a large ravine in Frick Park. The bridge opened in 1973 and collapsed on January 28, 2022.[1] The bridge was west of the intersection of Forbes Avenue and South Braddock Avenue, connecting the Squirrel Hill neighborhood with the neighborhoods of Point Breeze[2] and Regent Square.

History[]

Original bridge (1901–1972)[]

In February 1900, the "Councils of the city of Pittsburg" appropriated $100,000 for the construction of a street railway and highway bridge across Fern Hollow. A steel deck arch bridge was completed by Schultz Bridge & Iron Works (steelwork was subcontracted to American Bridge Company) and accepted on September 28, 1901.[3][4] The central arch spanned 195 ft (59 m) with a rise of 50 ft (15 m);[3][5][6] overall, the 1901 bridge was 438 ft (134 m) long and the vertical clearance under the bridge was approximately 94 ft (29 m) above the valley floor,[3] although later press reports stated it varied between 60–125 ft (18–38 m).[7][8] The roadway was 36 ft (11 m) wide, flanked on both sides by concrete sidewalks each 6 ft 6 in (1.98 m) wide. Unusually, the 1901 bridge was not built level, with one end being 15 ft (4.6 m) higher than the other.[6] The four-lane bridge also carried double rail tracks for streetcar service.[9]

Replacement bridge (1973–2022)[]

The 1901 bridge was replaced in 1973. The old bridge was closed in April 1972 and a new three-span steel rigid-frame bridge was built by Conn Construction Company for US$1,230,000 (equivalent to $7,610,000 in 2020), using COR-TEN weathering steel.[10] The replacement bridge, designed by the firm of Richardson, Gordon and Associates (founded by George S. Richardson),[11] opened on June 1, 1973,[12] and was presented with a Prize Bridge award for the medium-span, high-clearance category by the American Institute of Steel Construction in 1974.[11] Arthur W. Hedgren Jr. was chief design engineer and entered his design in the contest. Hedgren received a cash prize award and a summary of his ideas on this bridge design was published in a collection of winners.[13] The Lincoln Electric Company had created the James F. Lincoln Arc Welding Foundation to share knowledge about welding.

The bridge used two welded steel girders, supported at each end on reinforced concrete caps poured atop stone masonry abutments; the deck was supported by welded steel floor beams and rolled steel stringers. The rigid frame supports were inclined welded steel legs resting on reinforced concrete thrust blocks. The structural steel in the bridge and its inclined supports was not coated, as the weathering steel used was designed to develop a protective patina over time.[14]

Prior to its collapse in 2022, the 446.9-foot-long (136.2 m) replacement bridge had been listed by the National Bridge Inventory as being in poor condition since September 2011.[15] The posted weight limit of the bridge was 26 short tons (24 t)[16] and it carried more than 14,000 vehicles per day,[17] with a posted speed limit of 35 mph (56 km/h).[14] The bridge was inspected most recently on September 19, 2021.[18]

Bridge pier in 2015. The lower left-hand leg of the lowest X-brace was later found detached in 2018; the tensioned cables have been installed.

In December 2018, Greg Kochanski, a software engineer who frequently walked beneath the bridge, tweeted a photo he took at the base of the bridge.[19] He expressed concern to the city that one of the original X-shaped cross braces on a bridge pier had corroded and severed where the pier met the ravine. He had privately observed the bridge supports were "well rusted, which he presumed was because of a drainage problem where melting ice and snow with salt from maintenance was draining down onto the beams". Kochanski observed in his tweet that tensioned cables already had been installed to replace the function of the cross-bracing. The city's 3-1-1 system opened a tracking ticket three days later;[20] a few weeks after the ticket was opened, it was closed and the corroded cross brace was removed. Kochanski's tweet went viral following the bridge's collapse.[21]

Collapse[]

Collapsed Fern Hollow Bridge (Jan 29, 2022)
From the east end, looking west
From the west end, looking east
photographed by NTSB personnel

On January 28, 2022, at 6:39 a.m. EST, the Fern Hollow Bridge collapsed.[1][22] Nearby residents reported hearing a loud boom and a whooshing noise around 6:35–6:40 a.m. Many credited the early morning time of collapse for the lack of fatalities, as the bridge was a route for many school buses, PAT buses, and commuters to work.[23] Pittsburgh Bureau of Fire Chief Darryl Jones said it was very fortunate the collapse occurred before the morning rush hour.[24] The bridge was covered with a blanket of snow from an overnight storm that had passed through the area.[25]

Five vehicles were on the bridge when it collapsed, including a Port Authority articulated bus built by New Flyer in 2013. Another passenger vehicle drove off the eastern bridge abutment after the collapse and came to rest on its roof.[14] At least 10 people were injured; three were taken to hospitals by ambulances. None of the injuries appeared to be life threatening.[22] Some first responders rappelled about 150 ft (46 m) into the ravine, while others formed a human chain to rescue victims.[1] According to a law enforcement official, a passing jogger helped to rescue some of the motorists.[26] The count of ten injured included some first responders who slipped and fell during the rescue operation.[27] The initial rescue effort was completed by 8:30 a.m. EST while emergency personnel continued to check under the wreckage for any trapped victims;[1] none were found.[24] A crane erected at Forbes and Briarcliff was used to retrieve the wrecked vehicles, and the bus (22 tons) was lifted from the site on January 31.[28][29]

Under the road deck, the bridge carried a 16 inch (41 cm) natural gas pipeline,[17] which severed in the collapse. Local residents were evacuated from their homes in response to reports of a "massive leak" and strong scent of natural gas.[30] Officials shut down the gas lines in the area within a half-hour of the collapse.[25]

The bus, PAT fleet number 3309,[31] was operating route 61B outbound from downtown Pittsburgh (eastbound), and had nearly reached the east end before the bridge began to collapse.[17] Driver Daryl Luciani later reported "the bus was bouncing and shaking" during the event.[32] After the collapse, first responders placed a ladder by the bus door, which Luciani and the two passengers aboard used to descend to the floor of the valley before walking up to Forbes.[33]

Political response[]

President Joe Biden had been scheduled to visit Pittsburgh on January 28 to speak about infrastructure at Carnegie Mellon University's Mill 19.[1][25][34] After learning about the collapse, White House press secretary Jen Psaki confirmed via Twitter that Biden would continue with his planned speech to promote the Infrastructure Investment and Jobs Act.[35] Biden visited the collapsed bridge at approximately 1:30 p.m., before his scheduled speech,[26] and told reporters that he intended to direct funding to repair all 43,000 bridges in the U.S.[2][26]

Biden was accompanied by multiple Pennsylvania politicians, including Mayor Ed Gainey, Allegheny County Executive Rich Fitzgerald, Governor Tom Wolf, Lieutenant Governor John Fetterman, U.S. Senator Bob Casey Jr., U.S. Representatives Conor Lamb and Mike Doyle, State Senator Jay Costa, and State Representative Dan Frankel.[17] Gov. Wolf declared a state of disaster on January 28.[36]

Investigation[]

NTSB investigators under the collapsed bridge (Jan 28, 2022)

Shortly after the collapse, the National Transportation Safety Board announced it was sending a team led by Chair Jennifer Homendy to investigate the cause.[30][37] According to Homendy, the investigation will take 12 to 18 months to complete; the team began gathering evidence after their arrival on January 28.[17] In a January 29 press conference held after the first complete day on-site, Homendy stated a preliminary report would be available in approximately 10 days, but the final report would require "a long, technical investigation" reviewing bridge inspection reports and maintenance records, video (from local businesses and the PAT bus), traffic counts, weight requirements, and road treatments.[38]

The preliminary report was released on February 7.[14] The collapse apparently initiated at the west end of the structure.[14] No primary fractures were found in the critical areas of the welded steel girders.[14] PennDOT ordered reviews of structural adequacy for five bridges with similar rigid K frame designs immediately; the five bridges (Canon-McMillan Alumni Bridge in North Strabane, Shenango Road Bridge in Beaver, Philip J. Fahy Memorial Bridge in Bethlehem, McCallum Street Bridge in Philadelphia, and Murray Avenue Bridge over Beechwood Blvd in Pittsburgh) were found to be in "fair" condition at their last inspections.[39]

Reconstruction[]

Panoramic view of Fern Hollow from the east end (Feb 27, 2022). By this time, all broken bridge structures had been removed.

The city briefly made an observation site available, but closed it by February 2,[40][41] as the reconstruction effort began.[42] The replacement bridge will be designed by HDR, Inc. and constructed by Swank Construction of New Kensington; the contracts were awarded without bidding due to the emergency declaration and prior history with PennDOT.[43] Federal funds of $25.3 million were allocated for design and construction from the Federal Highway Administration's National Highway Performance Program, which in turn was funded by the Infrastructure Investment and Jobs Act of 2021.[44] During the first weekend in February, Swank moved demolition equipment to the site in preparation for removing the rubble. Building a new rigid K-frame bridge is unlikely, as the lead time for the steel required is more than 18 months.[45] The replacement bridge will be designed and built in sections; once HDR releases the design for a section, Swank will build it while HDR designs the next section.[43]

References[]

  1. ^ a b c d e Bella, Timothy; Sullivan, Sean; Duncan, Ian (January 28, 2022). "Pittsburgh bridge collapse injures 10 on day Biden to visit city to talk infrastructure". The Washington Post. Archived from the original on January 28, 2022. Retrieved January 28, 2022.
  2. ^ a b "Pittsburgh bridge collapses, President Biden visits site". WTAE Pittsburgh Action News 4. January 28, 2022. Archived from the original on January 28, 2022. Retrieved January 28, 2022.
  3. ^ a b c Wingate, Charles Frederick (February 15, 1902). "The Fern Hollow Highway Arch Bridge (Part 1)". The Engineering Record, Building Record and Sanitary Engineer. 45 (7): 156–158 – via University of Chicago.
  4. ^ Wilson, Todd (2015). Pittsburgh's Bridges. Charleston, South Carolina: Arcadia Publishing Incorporated. p. 77. ISBN 9781439653890.
  5. ^ Wingate, Charles Frederick (February 22, 1902). "The Fern Hollow Highway Arch Bridge (Part 2)". The Engineering Record, Building Record and Sanitary Engineer. 45 (8): 170–171. Archived from the original on January 30, 2022. Retrieved January 28, 2022 – via University of Chicago.
  6. ^ a b "A Steel Arch Highway Bridge At Pittsburgh, Pa". Municipal Engineering. XXXI (2): 96–97. August 1906. Archived from the original on January 30, 2022. Retrieved January 28, 2022.
  7. ^ "60-Ft. Leap Off Bridge Survived by Divorcee". Pittsburgh Post-Gazette. March 10, 1958. Archived from the original on January 28, 2022. Retrieved January 28, 2022.
  8. ^ "Girl's Plunge To Death Ends Wedding Spat". Pittsburgh Post-Gazette. January 6, 1958. Archived from the original on January 28, 2022. Retrieved January 28, 2022.
  9. ^ "Road Work to Limit Forbes Ave. Traffic". Pittsburgh Post-Gazette. February 17, 1969. Archived from the original on January 30, 2022. Retrieved January 28, 2022.
  10. ^ "Fern Hollow Bridge Job Is Delayed". Pittsburgh Post-Gazette. November 14, 1972. Archived from the original on January 30, 2022. Retrieved January 28, 2022.
  11. ^ a b "Prize Bridges/1974" (PDF). American Institute of Steel Construction. Archived (PDF) from the original on May 3, 2017. Retrieved January 28, 2022.
  12. ^ "It's Coming Friday!". Pittsburgh Post-Gazette. May 30, 1973. Archived from the original on January 30, 2022. Retrieved January 28, 2022.
  13. ^ Hedgren Jr., Arthur W.; Richardson, Gordon & Associates (1980). "Welded Rigid Frame Bridge Replaces Deteriorated Seventy-Year-Old Span". Modern Welded Structures. James F. Lincoln Arc Welding Foundation. IV: A6–A8. Retrieved February 4, 2022.
  14. ^ a b c d e f "Bridge Collapse | Accident No. HWY22MH003". National Transportation Safety Board. Archived from the original on January 28, 2022. Retrieved January 28, 2022.
  15. ^ "FORBES AVENUE over 9 MILE RUN & FERN HOLLOW". BridgeReports.com. Archived from the original on January 28, 2022. Retrieved January 28, 2022.
  16. ^ Gratzinger, Ollie; Linn, Virginia; Cook, Richard (January 28, 2022). "10 People Escape Serious Injury in Forbes Avenue Bridge collapse". Pittsburgh Magazine. Archived from the original on January 29, 2022. Retrieved January 28, 2022.
  17. ^ a b c d e Krauss, Margaret J.; Doyle, Patrick; Zenkevich, Julia; Schneider, Sarah (January 28, 2022). "Bridge collapses in Frick Park, hours before Biden arrives in Pittsburgh to discuss infrastructure". 90.5 WESA Pittsburgh NPR. Archived from the original on January 28, 2022. Retrieved January 29, 2022.
  18. ^ Niquette, Mark; Korte, Gregory. "Bloomberg - Bridge in 'Poor' Shape Was Checked Four Months Before Collapse". www.bloomberg.com. Archived from the original on January 29, 2022. Retrieved January 29, 2022.
  19. ^ Kochanski, Greg [@gpk320] (December 29, 2018). "@Pgh311 I hope someone is keeping an eye on the underside of the Forbes Avenue bridge over Frick Park? One of the big "X" beams is rusted through entirely (and, yes, I see the cables, so it's probably not a crisis)" (Tweet) – via Twitter.
  20. ^ @Pgh311 (December 31, 2018). "Service Request #307260 has been created. pittsburghpa.qscend.com/311/request/view/?id=ea13511a408a4282815637644fd5a13a" (Tweet) – via Twitter.
  21. ^ Hamill, Sean D. "Pittsburgh man's 2018 photo shows rusted support under bridge that collapsed in Frick Park". Pittsburgh Post-Gazette. Archived from the original on January 28, 2022. Retrieved January 28, 2022.
  22. ^ a b Rittmeyer, Brian C.; Guza, Megan; Cato, Jason (January 28, 2022). "10 injured in bridge collapse in Pittsburgh's Frick Park". Pittsburgh Tribune-Review. Archived from the original on January 28, 2022. Retrieved January 28, 2022.
  23. ^ Damp, Patrick (January 28, 2022). "'It Sounded Like A Huge Snowplow:' Neighbors Recall Sights And Sounds From Pittsburgh Bridge Collapse". Archived from the original on January 28, 2022. Retrieved January 28, 2022.
  24. ^ a b Wadas, Amy (January 29, 2022). "Bridge collapse: Family of victims share story". WDTV 5. Retrieved January 30, 2022.
  25. ^ a b c Abdel-Baqui, Omar; Lucey, Catherine (January 28, 2022). "Pittsburgh Bridge Collapses Near Frick Park Ahead of Biden's Visit". Wall Street Journal. ISSN 0099-9660. Archived from the original on January 28, 2022. Retrieved January 28, 2022.
  26. ^ a b c "Remarks by President Biden After Visiting the Site of The Collapsed Fern Hollow Bridge". The White House. January 28, 2022. Archived from the original on January 28, 2022. Retrieved January 29, 2022.
  27. ^ Fieldstadt, Elisha (January 28, 2022). "10 people injured after snow-covered bridge collapses in Pittsburgh". NBC News. Archived from the original on January 28, 2022. Retrieved January 28, 2022.
  28. ^ Krauss, Margaret J.; Schneider, Sarah (January 30, 2022). "The loss of the Fern Hollow Bridge means a scramble for alternate routes". WESA 90.5 Pittsburgh NPR. Retrieved January 30, 2022.
  29. ^ Hoffman, Chris (January 31, 2022). "Pittsburgh Bridge Collapse: Port Authority Bus Lifted Out Of Frick Park Ravine". KDKA 2 CBS Pittsburgh. Retrieved January 31, 2022.
  30. ^ a b Blazina, Ed; Bunch, Jesse; Goldstein, Andrew; Mamula, Kris B.; Routh, Julian; Stinelli, Mick; Strasburg, Stephanie (January 28, 2022). "'A boom, then a monster sound': 10 hurt after bridge over Pittsburgh's Frick Park collapses". Pittsburgh Post-Gazette. Archived from the original on January 28, 2022. Retrieved January 28, 2022.
  31. ^ Kilmer, Liz (January 28, 2022). "Pittsburgh bridge collapse: hear the chilling radio calls for help". WPXI-TV 11. Retrieved January 31, 2022.
  32. ^ Cipriani, Marcie (January 28, 2022). "Driver of Port Authority bus caught up in bridge collapse talks about experience". WTAE Action News 4. Archived from the original on January 29, 2022. Retrieved January 29, 2022.
  33. ^ Dawson, Jim. "'I could just feel it': PAT bus driver says he knew Pittsburgh bridge was collapsing beneath him". WPXI 11. Retrieved January 30, 2022.
  34. ^ Deto, Ryan (January 27, 2022). "What to expect from President Biden's Pittsburgh visit". Trib Total Media. Archived from the original on January 28, 2022. Retrieved January 28, 2022.
  35. ^ Deto, Ryan (January 28, 2022). "Biden visit to Pittsburgh still on following bridge collapse". Pittsburgh Tribune-Review. Archived from the original on January 28, 2022. Retrieved January 28, 2022.
  36. ^ "Gov. Wolf Declares Disaster Following Pittsburgh Bridge Collapse" (Press release). Governor of Pennsylvania. January 28, 2022. Archived from the original on January 29, 2022. Retrieved January 29, 2022.
  37. ^ @NTSB_Newsroom (January 28, 2022). "BREAKING NEWS: NTSB launching go-team to Pittsburgh bridge collapse. Chair Jennifer Homendy will be board member on scene. Arrival time this afternoon. Monitor Twitter @ntsb_newsroom for updates" (Tweet) – via Twitter.
  38. ^ Schneider, Sarah (January 29, 2022). "NTSB Chair: Fern Hollow Bridge damage 'takes your breath away'". 90.5 WESA Pittsburgh NPR. Retrieved January 30, 2022.
  39. ^ Felton, Julia (February 1, 2022). "PennDOT to reinspect bridges with similar design as Fern Hollow Bridge". Pittsburgh Tribune. Retrieved February 14, 2022.
  40. ^ Koscinski, Kiley (January 31, 2022). "There's now an observation area at the Fern Hollow Bridg ecollapse site". 90.5 WESA Pittsburgh NPR. Retrieved February 28, 2022.
  41. ^ Guza, Megan (February 2, 2022). "Fern Hollow Bridge collapse viewing area closed 'indefinitely' just 2 days after opening". Pittsburgh Tribune. Retrieved February 28, 2022.
  42. ^ Gratzinger, Ollie (February 11, 2022). "Timeline for Rebuilding Fern Hollow Bridge Still Uncertain, but Work is Underway". Pittsburgh Magazine. Retrieved February 28, 2022.
  43. ^ a b Blazina, Ed (February 4, 2022). "PennDOT selects team to replace Fern Hollow Bridge, says some demolition could start this weekend". Pittsburgh Post-Gazette. Retrieved February 28, 2022.
  44. ^ Felton, Julia (February 4, 2022). "Emergency contract to allow for design work to begin on Fern Hollow Bridge replacement". Pittsburgh Tribune. Retrieved February 28, 2022.
  45. ^ Shumway, John (February 7, 2022). "What To Expect As Demolition, Rebuilding Process Begins At Site Of Fern Hollow Bridge Collapse". KDKA 2, CBS Pittsburgh. Retrieved February 28, 2022.

External links[]

Collapse[]

Data[]

Investigation[]

Retrieved from ""