Fort Pitt Bridge and Tunnel carries Interstate 376 over the Monongahela River and under Duquesne Heights in Pittsburgh, Pennsylvania.
The first fixed crossing of the Monongahela River at Fort Pitt was the Point Bridge, a chain suspension structure designed by Edward Hemberle and constructed by the American Bridge Company in 1877. It was replaced with a warren through truss designed by George S. Richardson of Richardson, Gordon, & Associates and Stanley L. Rousch and constructed by the Dravo Contracting Company and Fort Pitt Bridge Works in 1927.
The Point Bridge was becoming increasingly overburdened because of the rapid development of neighborhoods south of downtown, an area that had become referred to as South Hills. 4 5 While there was some relief with the completion of the West End Bridge, Saw Mill Run Boulevard, and Banksville Road, there was ongoing congestion in getting around Mount Washington. The idea of building another bridge across the Monongahela River and a tunnel under Mount Washington began in 1924. It gained traction as part of a circa 1939 modernization proposal by famed urban planner Robert Moses.
Initially, designers proposed building two 3,750-foot-long tubes through Mount Washington that would connect to an accompanying bridge slightly upriver from Point Bridge which would connect to Water Street in downtown. 4 5 The $8 million project was postponed because of a lack of funding and the onset of World War II.
The bridge and tunnel proposal was revised in the late 1940s as part of Pittsburgh’s Renaissance I initiative which would link the proposed Penn-Lincoln Parkway south of Mount Washington to the North Shore across a bridge over the Monongahela and Allegheny Rivers. 4 5
Debates ensued for three years while city and state officials debated on whether to allow trolley tracks to be built into the plans as the Pittsburgh Railways Company argued that if Fort Pitt Bridge was built without tracks, it would destroy the West End trolley network. 4 Local and state planners countered that slower-speed trolley tracks would interfere with the proposed high-speed Penn-Lincoln Parkway. The State Public Utilities Commission (PUC) eventually decided in favor of the omission of the trolley tracks. The decision was challenged in the courts and it wasn’t until January 1956 that the Pennsylvania State Superior Court upheld the decision from the PUC.
Preliminary test borings for the piers for the new Fort Pitt Bridge began in January 1953 with construction beginning immediately by the American Bridge Company after the court decision from the state’s Superior Court. 3 4 Amid much fanfare, the new crossing was dedicated on 11 AM on June 19, 1959. The ribbon-cutting ceremony was attended by Governor David L. Lawrence, Mayor Thomas Gallagher, and mayoral candidate Joseph M. Barr who were driven across in a caravan while a city fireboat gave a hose salute upriver. 2
The new crossing, the world’s first computer-designed bowstring arch bridge 1 4 and double-decked bowstring arch bridge, 2 4 contained 8,066 tons of steel, 4,950 tons of structural carbon steel, and 1,305 tons of steel reinforcing rods. 4 It cost $6.3 million to complete while the boring of the Fort Pitt Tunnels cost an additional $16 million. The Point Park Portal Bridge and Fort Duquesne Bridge added another $6.9 million.
The Point Bridge was closed to traffic on June 21 and remained abandoned in place until it was demolished in 1970. 4
Prior to the construction of Fort Pitt Tunnels, a traffic circle was the connecting link between Saw Mill Run Boulevard, Banksville Road, and Woodville Avenue. 5 It saw frequent congestion with traffic from the South Hills to downtown had to navigate southward to the Liberty Tunnels or north along Woodville Avenue to the West End Bridge. The completion of the West End Bypass helped alleviate some of the congestion while providing direct access to the West End Bridge.
Fort Pitt Tunnels were envisioned as a pair of tolled facilities. 5 Plans called for 11 traffic lanes funneling to 10 toll booths at the south end of the tunnel. To alleviate anticipated congestion at the booths, the state would issue monthly stickers to regular users. After much protest, the tolling plan was dropped from consideration.
In early 1956, the Fort Pitt Tunnel Commission announced that the boring of the twin two-lane tunnels would begin in the fall. 5 The ground-breaking ceremony was held on April 17, 1957, and the boring of the tunnels began on August 28 and progressed on average 46 feet per day. The boring process was completed by May 1958 and both tunnels opened to traffic at the cost of $17 million on September 1, 1960.
The tunnels featured a roadway surface finished with paving bricks, with the walls lined with bright reflective tiles and a dropped tile ceiling to increase illumination. 5 An antenna that ran the length of each shaft was installed that allowed motorists to pick up AM and FM radio. Four huge blowers at each end kept the tubes cleared of exhaust fumes. A control room was fitted with television screens to monitor traffic in real-time.
Originally painted gray, the Fort Pitt, Fort Duquesne, and West End bridges were all painted in Aztec Gold between 1978 and 1981; the Fort Pitt bridge itself was repainted at the cost of $2.3 million in 1980-81. 4 Fort Pitt Bridge was extensively rehabilitated over an eleven-year span between 1993 and 2004 at the cost of $200 million. 4 5 Work involved structural steel replacement, roadway deck replacement, and repainting of the superstructure. For the tunnel, work began in 1993-94 with a replacement of the granite and metal facades at the portals at the cost of $3.8 million. 5 Between 2002 and August 2003, the tunnels themselves received a new roadbed, and the replacement of the wall tiles, electrics, lighting, and drainage. The dropped ceiling tiles were removed.
- State: Pennsylvania
- Route: Interstate 279
- Type: Steel Arch, Tunnel
- Status: Active - Automobile
- Total Length: 1,245 feet (1877 bridge); 1,330 feet (1927 bridge); 1,207 feet (1959 bridge); 3,614 feet (1960 tunnel)
- Main Span Length: 800 feet (1877 bridge); 430 feet (1927 bridge); 752 feet (1959 bridge)
- Deck Width: 34 feet (1877 bridge); 38 feet (1927 bridge); 52 feet (1959 bridge)
- Above Vertical Clearance: 14.1 feet (1959 bridge)