“Poor Condition” Forbes Ave Bridge Collapsed Yesterday

Posted on January 29, 2022 by Carolyn Ristau

Yesterday, after the Fern Hollow Bridge collapsed in Pittsburgh a photo circulated on social media of one of the steel support beams of the bridge completely rusted through. This photo was taken in 2018 and reported to the City’s 311 system. While the photo also showed cables that had been added to the bridge to presumably take over the job of the steel beam that then ended in mid-air, the person submitting the photo was concerned that this might not be sufficient. I have seen similar rusted conditions on other bridges that I have walked over or under in Pittsburgh. I cannot remember if it was the Negley Ave bridge over the busway, the Charles Anderson Bridge over Junction Hollow in Frick Park, both, neither, or a handful of other bridges. (Note: both of these bridges are rated in poor condition.)

A neighbor quoted in a Tribune Review article after the Fern Hollow Bridge collapse wondered why the bridge hadn’t been repaired or replaced before the accident since it was known to be in poor condition. According to BridgeReports.com, which pulled inspection data on the bridge from 1991-2017, the bridge has been rated as in poor condition since 2011. Based on my experiences and exposure to bridges, I am not surprised that a bridge was left in poor condition for over a decade. This morning, I pulled data from the National Bridge Inventory on the 449 inventoried bridges within a 6-mile radius of downtown Pittsburgh. I was surprised to find that only 10% of these bridges were rated in poor condition.

Below is a chart of the 48 bridges rated in poor condition within a 6-mile radius of downtown, which includes some that are outside the boundaries of the City of Pittsburgh. In those cases, the city owner would be the municipality they are within. The first four columns are the data I pulled from the National Bridge Inventory, the final column is from BridgeReports.com. Both sources were updated through 2018, which means that there have been some changes since then, including the possibility that more bridges have fallen into a poor state. I marked in italics the bridges that I am heard went through renovations in recent years and in bold the one that collapsed. The bridges with hyperlinks are the ones that I have walked and blogged.

Owner	Bridge Description	Year Built	Year Renovated	Rated Poor Since
State	Island Avenue Bridge	1900	–	–
State	Wetzel Rd over Pine Creek	1936	–	–
State	Blvd of Allies over cliff	1950	–	2018
State	Blvd of Allies over Forbes	1952	1984	2017
State	Ramp U over Old Brady St	1954	1985	2013
State	Ramp R over Brady	1956	1985	2017
State	Ramp H over Forbes, Diamond, 6th Ave	1962	2012	1997
State	Peoples Rd over Girtys Run	1963	–	–
State	Washington Ave over P&O RR	1965	–	–
State	Ft Duquesne to 10th St	1968	1988	–
State	Blvd of Allies over another cliff	1981	2001	2018
Railroad	West Ohio St over NS RR	1903	1958	1991
Railroad	N Ave & Brighton Rd over NS RR	1905	1929	2009
County	9th Street – Rachel Carson Bridge	1926	1994	2013
County	Jacks Run Rd over Jacks Run	1980	2019	–
County	Wible Run Rd over Wible Run	1987	–	–
City	Second Ave over Nine Mile Run	1886	–	at least 1991
City	Shaler St over Saw Mill Run	1900	–	at least 1991
City	Lowrie St over Rialto St	1900	1972	2008
City	Elizabeth St over Gloster St	1900	1979	2014
City	Ridge Ave over NS RR	1903	1957	at least 1991
City	Timberland Ave over Saw Mill Run	1909	–	at least 1992
City	Fremont St over Girtys Run	1911	–	–
City	Lincoln Ave over Girtys Run	1911	1950	–
City	Larimer Ave over Washington Blvd	1912	–	at least 1991
City	Grant Ave over Girtys Run	1914	1986	–
City	Klopper St over Girtys Run	1915	–	–
City	Lincoln Ave over Girtys Run	1915	1986	–
City	Frazier St over Saline St	1915	1989	2007
City	S Negley Ave over E Busway	1924	1973	at least 1991
City	W Carson St over Chartiers Creek	1925	1978	2009
City	Ansonia Pl over Saw Mill Run	1925	1998	1995
City	Maple Ave over N Charles St	1929	1953	at least 1991
City	Swindell Br over East St	1930	1990	2009
City	Calera St over Streets Run	1931	–	at least 1991
City	28th St over Busway & RR	1931	1974	at least 1990
City	E Main St over Chartiers Creek	1934	2002	–
City	Charles Anderson Bridge	1938	1987	2012
City	Mission St over S 21st St	1939	1982	2010
City	River Ave over Bike Trail	1939	1986	2008
City	Ganges Way over Streets Run	1951	–	2016
City	E Liberty Blvd SB over walkway	1968	–	2009
City	Forbes Ave over Fern Hollow	1970	–	2011
City	Herron Ave over Busway & RR	1980	–	2018
City	McArdle over Sycamore St	1983	–	2017
City	Milroy St over I-279	1986	–	2011
Other Local Agency	Centre Ave over East Busway	1979	–	2008
Other Local Agency	Penn Ave over East Busway	1981	–	2018

Breaking News: Fern Hollow Bridge Collapse

Posted on January 28, 2022 by Carolyn Ristau

A bridge collapsed in Pittsburgh this morning. While not an iconic bridge, the Forbes Avenue Bridge over Fern Hollow was significant as the sole road link over Frick Park. With this link missing, motorists and those using public transit will have to travel several miles out of their way through some very congested roads. Pedestrians and bicyclists have some shorter options using the park’s trails.

The bridge was built in the early 1970s and as far as I know has not had any significant maintenance work done since then. It is owned by the City of Pittsburgh. Based on the National Bridge Inventory by the Federal Highway Administration, the bridge was in “Poor” condition, had an inspection frequency of 18-24 (units were not included, hopefully this is months), the structural evaluation was “Minimally Tolerable,” the substructure was rated “Satisfactory” while the superstructure was rated “Poor,” average daily traffic was 10,000-15,000, and the detour route would add 2-5 miles. In addition, this site estimates the replacement cost at $6.5 million. I could not find the date of the last inspection on the NBI site. Based on a summary of inspections on BridgeReports.com, which sites the NBI as its source, the bridge was inspected every two years between 1991 and 2017, so presumably there were additional inspections in 2019 and 2021.

There was a bus and some other vehicles on the bridge when it collapsed. The two passengers on the bus were taken to a hospital with “minor injuries” as was a third person. Seven other people are reported to have “minor injuries” that did not require a hospital visit. The City’s first official press release on this disaster says that rescue efforts concluded at 8:30am, but that underneath the bridge was still being checked for potential victims – some of the park’s well-used trails pass underneath. WTAE has videos from the scene; the Tribune Review has quotes from nearby residents on what they heard and saw this morning. This story has also made national news with coverage by on the US News and World Report website.

The coincidences: President Biden is scheduled to speak in Pittsburgh today about infrastructure, including bridge maintenance, the overnight snow may have limited vehicular and foot traffic over and under the bridge, and I just happened to be somewhere where the news was on this morning in time to see the first news report on WTAE (I never watch or read the daily news).

Mayor Gainey is quoted as saying “we were fortunate.” The people using the bridge were unfortunate that the bridge collapsed when it did, but given that it did collapse, they were fortunate in that it appears there are no serious injuries and no deaths. It was also fortunate that the collapse happened before rush hour and on a bridge that was over land. If this was one of our river bridges or if it happened during rush hour, serious injury and death seem impossible to avoid.

Deferred maintenance of bridges is a real and serious thing. Bridges are a crucial part of our daily lives (especially in places like Pittsburgh). Every time I walk over the Negley Ave bridge over the busway, I warily eye the rusted structure. The old Highland Ave bridge over the busway used to spark the same reaction, but it was fortunately replaced several years ago. The Smithfield Street bridge has holes through the sidewalk. How far do we push our “poor” condition bridges before investing in maintenance and repair?

Then & Now: 16th Street Bridge

Posted on January 15, 2022 by Carolyn Ristau

urbantraipsing turns 10 in May. To mark a decade of urban-traipsing and bridge-walking, I will be revisiting twelve of the Pittsburgh bridges I walked early on to see the changes 10 years brought to them and their surroundings.

I started walking and photographing bridges to get different angles and views of the city. In 2012, the 16th Street Bridge provided views of two major, controversial development sites: the Produce Terminal and the former St. Nicholas Croatian Catholic Church.

During the summer of 2012, the Produce Terminal seemed on the cusp of being redeveloped, and partly demolished. However, significant opposition to the demolition plans killed that proposal. For years there was no visible progress. Eventually, after extensive negotiations, a new development proposal was approved and implemented (see the first photo pair below). Simultaneously, several new developments popped up nearby, replacing much of the sea of parking I complained about in my original post on the bridge (see the second and third photo pairs below).

The former St Nicholas Croatian Catholic Church was visible from the 16th Street Bridge in 2012. Six months later, it was demolished to make way for the widening of Route 28 despite parishioners efforts to save their church (see a 2013 Tribune Review article for more). I followed the story of their fight for their building closely at the time, which is what I believe prompted me to take a photo of the church from the bridge (see the fourth photo pair below).

View of inland side of Produce Terminal (Smallman St)
June 2012

A Structurally Unsound Bridge

Posted on January 1, 2022 by Carolyn Ristau

This year’s Architectural Dessert Masterpiece was inspired by a trip to Vermont where I explored 14 covered bridges within an hour’s drive of Rutland. I was surprised by the amount of variety in these bridges. Most were only wide enough for one car lane, but one was definitely made for two-way traffic and a couple had sidewalks incorporated. The colors and shapes varied from bridge to bridge. Some appeared to be based on a truss-type structure while at least one looked like it had an arch infrastructure. Ages also ranged from the 1830s (Taftsville Bridge) to 1970s (Quechee Bridge). You can view all 14 bridges in the slideshow below.

Sadly, shortly after construction, my covered bridge experienced a collapse. While the incident is still under investigation, an anonymous authority stated that the collapse is believed to have been trigged by a motorist exceeding the posted 5 mph speed limit.

I’m surprised that this is my first total collapse over the eight Architectural Dessert Masterpieces that I’ve created. My first, the Parthenon, experienced a partial collapse that actually made it look even more like the original. The next closest to disaster was the Marina Tower that merged into the Leaning Tower of Pisa.

The collapse highlighted several tips for future constructions. First, I confirmed that pretzels really do make excellent piers as I originally demonstrated in my Pittsburgh suspension bridge. Second, I learned that wheatless gingerbread still has the same (or similar) strength as traditional gingerbread as the roadbed remained secure throughout the disaster. Third, I found that wheatless gingerbread is more pliable than traditional gingerbread, which resulted in more warping when transferring the pieces to the baking sheet and during baking. However, the other side of the pliability is that it is easier to trim after baking than traditional gingerbread. If I use this recipe again, I will plan to make adjustments to the dimensions of the pieces post baking. I believe that will resolve the structural issues by creating straight edges that can support each other.

Vermont Covered Bridge Slideshow

Worrall Covered Bridge
Brown Covered Bridge
Cooley Covered Bridge
Bartonsville Covered Bridge
Depot Covered Bridge
Gorham Covered Bridge
Hammond Covered Bridge
Kingsley Covered Bridge
Lincoln Covered Bridge
Middle Bridge
Quechee Covered Bridge
Sanderson Covered Bridge
Taftsville Covered Bridge
Kissing Bridge

Hebron Snow People

Posted on January 1, 2022 by Carolyn Ristau

Pittsburgh dinosaur hunting is on pause this month. Instead, the public art feature of this month is from Hebron, CT. Hebron is a typical small Connecticut town built up at a crossroads. It was incorporated in 1708 and its current population is just under 10,000. In passing through on a recent trip around New England, my eye was caught by a public art display of snow people on the town green. I originally assumed that this was one of the fiberglass fundraisers like the Pittsburgh DinoMite Days dinosaurs, however these snow people are made of Styrofoam. However, like the fiberglass statues, each one is decorated by a different artist. They seem to be a new annual tradition of the town, having first appeared in the winter of 2020 then hibernating over the summer before returning this winter. Scroll through the slideshow below to see all eight of the snow folks (my favorite is the hula dancer).