Looking at the various ramps on Google Maps, the bridge carries I-279 on the northwestern lanes and I-376 on the southwestern lanes. And I-279 becomes local traffic on the south side of the river. It also carries US-22, US-30 (Penn Lincoln Parkway West) and US-19 Truck.
I discovered this tunnel while looking for the Duquesne Incline because I recognized I-376 as the road over which the W&LE/N&W/P&WV/Wabash railroad had two trestles. And a tunnel for that railroad is on the other side of the Sawmill Run Valley. Pittsburgh is not only the city of bridges, it is a city of tunnels.
There are NO shoulders in the tunnel. That must make it rather scary to drive through because they have signs posted to "MAINTAIN SPEED THRU TUNNELS." Does that tow truck always park there so that they can quickly yank any disabled vehicle out of the 3,614' long tunnel?
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| HistoricPittsburgh-tunnel Title: Fort Pitt Tunnel during Construction Creator: Pennsylvania Department of Highways Identifier: MSP285.B011.F06.I03 "Description: The 3,614 foot long, over 28 foot wide Fort Pitt Tunnel opened September 1, 1960, as the last link in the Penn Lincoln Parkway. The Fort Pitt Tunnel groundbreaking ceremony was held April 17, 1957, and the drilling began on August 28. Estimated cost for the new tunnels was $17 million." "Of the highway tunnels in Allegheny County, the Fort Pitt Tunnels are third in length behind the Liberty Tubes (5,889 feet) and the Squirrel Hill Tunnels (4,225 feet) on the Parkway East." [$17m is worth $158m in 2021. I can't imagine that those tunnels could be built that cheaply today. There must be other differences in addition to inflation such as the cost of preparing environmental impact statements.] |
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| PittsburghMagazine [One of several construction photos in this article.] Jackson-Township historical preservation posted Interior view of the Fort Pitt Tunnels under construction in Pittsburgh showing debris removal equipment loading blasted rock in 1958. As rock was blasted, the truck-mounted “jumbo” drilling rig was driven out of the tunnel to permit debris to be cleared out. Lining the sides and top of the tunnel are eight-inch-wide, steel-ribbed supports, spaced four feet apart. Supports, later encased in concrete, kept rock in place. (Photo and text from https://historicpittsburgh.org/) Leo Treible: Cables dozer,open cab haul truck...gotta love that in a tunnel. |
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| BrooklineConnection It was "the first tunnel in the world in which portal traffic at one end moves over two different levels. The northern portals are vertically offset to allow traffic to mesh with the double-deck construction of the accompanying Fort Pitt Bridge." "Inbound traffic crosses the bridge on the upper deck. Outbound traffic uses the lower bridge deck and passes into the tunnel portal approximately forty feet lower in elevation. The outbound bore gradually rises to meet the elevation of its neighbor so that the southern portals are equal in elevation." "An antenna that ran the length of each shaft, powerful enough to pick up both AM and FM radio, something new at the time for Pittsburgh motorists. Four huge blowers at each end keep the tubes clear of exhaust fumes....A control room at the southern portal has television screens to monitor traffic and a large panel with dials and switches that operate the various electronic functions. The use of television to monitor tunnel traffic was also believed to be a world first." |
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| BrooklineConnection "Nicknamed "Jumbo" this $130,000 34-ton truck with mounted drilling platform was used to bore through Mount Washington." The caption of a photo of the Jumbo at the tunnel face states: "Boring began on August 28, 1957, using twelve pneumatic hammer type drills, mounted on "Jumbo's" platform." |
The tunnels were dug from the south portal to the north portal.
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| BrooklineConnection "The Fort Pitt Bridge and Tunnels (circa 1960.)" "When the tunnel opened the average usage was 40,000 vehicles per day. By 2018, that number had risen to 150,000." There are proposals to add two more bores to help alleviate rush hour traffic jams. [Note the 1927 Point Bridge in the background that is being replaced by this bridge.] |
Fort Pitt Bridge
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| Jackson-Township historical preservation posted Newly opened Fort Pitt Bridge in Pittsburgh after the Grand Opening in 1959. (Photo from Harold Corsini via https://www.facebook.com/OddPittsburgh/) |
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| Jackson-Township historical preservation posted Fort Pitt Bridge under construction looking towards the Golden Triangle in Downtown Pittsburgh in the 1950's. (Photo from Frank Clement via https://www.facebook.com/groups/132768683480072/) |
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| HistoricPittsburgh-bridge Title: Fort Pitt Bridge Creator: unknown Identifier: MSP285.B008.F18.I02 Description: View from Mount Washington showing the Fort Pitt Bridge under construction and downtown in the background. The Fort Pitt Bridge was opened on June 19, 1959. It was opened to traffic 15 1/2 months before the Fort Pitt tunnels were opened. The length of the main span is 750 feet with a total length, including longest elevated ramp, of approximately 1217 feet. The height of the deck is 47.1 feet at the northern pier. |
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| Bridges Now and Then posted Pittsburgh's Fort Pitt Bridge, c. 1959. (Brookline Connection) Kathy Phillips Morus: Traffic is already backed up! |
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| BrooklineConnection-bridge "Designed by engineer George S. Richardson, the Fort Pitt Bridge is a steel, double-decked tied arch bridge that spans the Monongahela River. It is the world's first computer designed tied arch bridge, and at the time of it's dedication the only bridge of its type in the world. Preliminary test boring for the piers began in January 1953 and actual bridge construction began in January 1956." [This is one of several construction photos in this article. I chose this one because it provides another view of the now lost Point Bridge in the background.] |
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| Heinz History Center posted, cropped This week [Jun 18, 2024,] in 1959, the Fort Pitt Bridge opened to the public. The double-deck, steel bowstring arch bridge is approximately 1,217 feet with a deck height of 47.1 feet at the northern pier. Known for its complicated lane changes, the bridge crosses the Monongahela River and carries Interstate 376 between the Fort Pitt Tunnel and Downtown Pittsburgh. 📸 Construction of the Fort Pitt Bridge. Pittsburgh Public Schools Photographs, Detre Library & Archives at the Heinz History Center. Jay Krajcovic shared |
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| Jackson-Township historical preservation posted Photo of the Fort Pitt Bridge under construction in Pittsburgh in the 1950's. It was the world's first computer designed bowstring arch bridge. (Photo from Gary Weslager via https://www.facebook.com/groups/132768683480072/) Dan McCarthy: The first bridge analyzed by computer was the Fort Duquesne bridge. The analysis was done at American Bridge by Ed King and Ron Strahn. Tim Fetty: What's the fundamental difference between a bowstring arch and a suspended truss? John Tkacs: Tim Fetty I am not familiar with the term "bowstring arch". In typical arch bridges, the arch elements connect to the ground with thrust blocks and the thrust blocks keep the arch from its tendency to spring apart under loads. There are no thrust blocks here, only the bridge piers. The arch is kept from springing apart with the truss element that spans the piers. It keeps the arch tied together and the term I'm used to seeing for this type of bridge is a "Tied Arch." A suspended truss is typically a portion of the center span of a three span continuous truss. The bridge is constructed in both directions from the piers and when construction gets closer to the center of the bridge, the final piece is a separate truss that is held in place with large pin connections. I believe this approach is no longer used due to the difficulty in inspecting the pin connections for deterioration. I hope this helps! |
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| USACE, Pittsburgh District posted 🚢 Pop Quiz Time! 🚢 📢 Do you know the name of the boat that pushes barges on rivers in the Pittsburgh area? 👨✈️ Photo by Michel Sauret Joseph Yeater: Tow boat or in specific the MV Evanick pushes the USACE barges and equipment based on Neville Island. [Several comments spelled towboat as two words.] |
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| BrooklineConnection-bridge [An arch requires quite a bit of falsework until it is closed.] Bridges Now and Then posted Pittsburgh's Fort Pitt Bridge under construction, Summer, 1958. The second Point Bridge can be seen behind. (No photo credit found) |
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| Allegheny City posted Fort Pitt Bridge Under Construction. Notice that the tunnels have been bored out but not cleared in front. Let this be confirmation that the original steel was yellow although it was painted a greenish gray before returning to the current Aztec Yellow. Search our page using the keyword BRIDGE for other photos we posted a few years ago. Richard Butterworth: I would have thought they built the arch first, followed by the stringers, then deck. But for this bridge, as the arch and deck are a combined system (where the base of the arch is dependent on the tensile strength of the deck to keep it from deforming), I understand why they used a different approach. [1958] |
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| Bridges Now and Then posted Building Pittsburgh's Fort Pitt Bridge, c. 1958. The Point and Manchester Bridges can be seen to the left. (Brookline Connection) |
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| Allegheny City commented on their post Red oxide primer on right, first original greenish Gray on left .. The current aztec yellow was painted in 1980. |
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It was painted Aztec Gold in 1980-81. "Beginning in 1993, the Fort Pitt Bridge and Tunnels underwent an eleven-year rehabilitation. Done in stages, the $200 million project began with the replacing of the granite and metal facades on the tunnel portals, then proceeded to a complete renovation of the bridge and associated ramps." [BrooklineConnection-bridge]
Richard Sharp posted six photos with the comment: "The construction of the Fort Pitt Tunnel and Bridge."
Donald Craig: Earth from the tunnels filled in the swamp between Ingram and Crafton creating a shopping center.
Terry Stell: https://www.pennlive.com/life/2017/04/fort_pitt_tunnel_construction.html [Give it time for it to download its advertisements, then it finally settles down so that you can view seven photos.]
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| 2 [The old point bridges are on the left.] View Pittsburgh posted Donald Glunt: Nice pic. One detail out of place. The Fort Pitt Bridge was silver gray until the current color called “Aztec Gold” was applied in 1978. Roy Scott: The guy in charge of delivering the different kinds of steel was color blind...The steel was marked with color bands...As a result some of the steel was in the wrong place and had to be redone etc. I know this since my Dad was a head cost accountant for American Bridge at US Steel, and he had to compute the cost of the steel mistake. Sue Todd Krouse: Roy Scott I don't know how many bridges you've worked on. But this bridge was built in a fab shop "American Bridge shop" each piece was fabricated and fitted before it ever showed up on site. It was checked by a detailer checked by an ironworker then checked again by a shop foreman. There may have been color coding on it. But there was also match marks on each piece and every single piece of iron had its own number for identification. There may have been some pieces put in the wrong spot and needed to be switched out or wrong end to. But even that would be hard to believe. If you think an ironworker superintendent, the walking boss, the raising gang pusher, two hook men and several connectors were setting iron by color coordination your out of your mind.When ironworkers set pieces on a bridge the piece number is checked probably twenty times before it leaves the ground or barge. Along with orientation of each piece for top, bottom along with direction north, south , east or west. No ironworker on earth trusts anything the guy delivering it has to say. Even if they did switch some pieces out you think they are calling the accountant and tell him about it? I've put a few pieces in wrong but never enough to call the accountant. Someone is feeding you a line of BULL. |
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| Domo Folino commented on Richard's post Euclid made very few of these trucks for this project two of them are restored at National Pike Steam, Gas and Horse Association |
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