Smithfield Street Bridge
The Smithfield Street Bridge, built in 1881-1883, is Pittsburgh's oldest surviving river bridge. The venerable span enters it's 132nd year of service in 2014. It's unique design and stunning longevity have made it a Pittsburgh treasure as well as a national monument.
Despite it's age, the Smithfield Street Bridge remains one of the city's main arteries connecting the northern and southern shores of the Monongahela River. In addition to high automobile and transit use, the pedestrian walkway is a vital link between the Golden Triangle and the many attractions across the waterway at the Station Square complex.
The First Monongahela Bridge
The present structure is actually the third rendition of the bridge. The first in this Trinity of Bridges was a covered wooden structure known as the Monongahela Bridge. It was designed by Louis Wernwag and built from 1816 to 1818 at a cost of $102,000. The toll bridge, owned by the Monongahela Bridge Company, was the only one to span the Monongahela, linking Pittsburgh to the growing municipalities to the south.
The heavily-traveled bridge was seriously damaged in 1832 by a runaway boat. Two complete sections collapsed into the river when the craft struck a pier. After extensive repairs, the Monongahela Bridge stood for another thirteen years before being completely destroyed during the Great Fire of 1845.
After the fire, the old piers and abutments were quickly repaired. A contract was issued for $55,000 to John A. Roebling for the construction of a new wire cable suspension bridge. For Roebling, the Monongahela span would be his first highway bridge.
A few years later, Roebling also designed Pittsburgh's Sixth Street Bridge replacement. Using the knowledge gained on these projects, Roebling went on to become one of the country's most prominent architects, and the designer of the famous Brooklyn Bridge.
The Second Monongahela Bridge
Making use of the old piers and abutments, work was begun on the new bridge in June 1845. The span measured 1500 feet and was built in eight sections, each supported by two cables suspended from large cast iron towers atop each pier. The two single cables ran through pendulums at the top of each tower, a revolutionary design at the time. The width of the bridge measured thirty-two feet, including five foot sidewalks on each side.
The new Monongahela Bridge opened to traffic in February 1846. Once again, it was a financial success. Still the only bridge across the Monongahela River, it handled the majority of coal traffic from the South Hills mines into the city, and was heavily used for pedestrian and horse-drawn wagon traffic.
In 1859 the Pittsburgh and Birmingham Railway Company began a horse car line and installed tracks along the bridge. The agreed upon toll charge was $15 per car each month. Then, in 1861, a second bridge was constructed across the Monongahela River, called the South Tenth Street Bridge. From that point on, the Monongahela Bridge was increasingly refered to as the Smithfield Street Bridge.
The bridge remained in service for thirty-five years. During this time, the rapid growth of the city brought with it a substantial increase in vehicular traffic. The light-weight suspension bridge carried the heaviest kind of street traffic, including the horse cars, steam rollers, and eight-horse teams pulling heavy trucks loaded with iron, coal and machinery. Despite the added strain, the bridge performed well.
By the 1870s, however, it became evident that a larger, sturdier bridge was needed to carry the ever-increasing burden. In 1880 the decision was made to demolish the Roebling bridge and construct a new span. The following year another famous German-born bridge engineer, Gustave Lindenthal, was chosen to design the structure.
The Smithfield Street Bridge
Work on the lenticular truss bridge began in 1881. One challenge encountered was to allow for the continued flow of traffic on the old Roebling Bridge while construction proceeded on the new span. The Lindenthal bridge, made of steel and iron, was built twenty feet higher than Roebling's, which remained in operation during the entire two-year construction period. It is one of the first bridges in America to use structural steel in the design.
The new Smithfield Street Bridge built at a cost of roughly $500,000. It opened to traffic on March 19, 1883. At this time the abandoned Roebling was dismantled and the old stone piers removed. Gaps in the new piers, designed around the old bridge, were filled in with masonry. As with it's predecessors, a toll was required to cross the bridge.
When initially completed in 1883, the bridge had only a pair of trusses and one roadway, built for two lanes of vehicular traffic, including two sets of tracks for streetcar traffic. On either end of the bridge stood large, ornamental cast-iron towers with attached wrought-iron roofs. Along the north and south abutments were the toll houses. The original color specifications were: iron work under the flooring were painted brown, iron and steel work above the flooring were blue, and the towers were a stone color.
Adding The Third Truss
The Smithfield Street Bridge was built with expansion in mind. The stone piers were wide enough for the addition of a third truss and a second roadway. Eight years after the initial dedication, in 1891, designer Gustave Lindenthal returned to supervise the installation of the third truss on the upstream side of the bridge. This new traffic lane was wide enough for only one set of rails as opposed to two on the downstream side.
In 1895 the City of Pittsburgh bought the span from the Monongahala Bridge Company for $1,150,000 and eliminated the toll charges, thus opening the bridge to the public. This policy was initiated with most of the bridges over the Monongahela and Allegheny Rivers, providing free access to the city for all residents of the northern and southern municipalities.
Widening The Bridge
In 1911, the Smithfield Street Bridge underwent another major expansion project when the third truss was moved several feet upstream to create a two lane roadway on each side. The bridge width had now more than doubled since 1883, from twenty-three to forty-eight feet.
At this time the Pittsburgh Railways streetcar tracks were moved completely to the upstream side. There were now two lanes of the bridge dedicated to the streetcars and two lanes solely for vehicular traffic. Two ten foot pedestrian sidewalks stood on decking installed on the outside the trusses. The Smithfield Street Bridge had now reached the full dimensions envisioned by Lindenthal when he created the design.
During the 1911 reconfiguration, the large cast-iron north and south portals, which stood on the bridge's downstream side only, were dismantled and removed. The original color scheme was abandoned and the bridge was repainted entirely in a grayish silver paint. It would remain that color until 1995.
Another change that came during this construction phase was the addition of a sizeable canopy that covered all four lanes. It was located on the southern abutment next to the P&LERR Terminal Building. Near the apex of the roof was a large clock visible to inbound travelers.
The portals were eventually replaced, in 1915. The new design, by City Architect Stanley Roush, was much simpler yet equally as elegant as the prior portals. The new design featured ornaments in the form of a miner holding a pick and a man holding a gear. It also included the City of Pittsburgh Coat of Arms above each gateway.
Aluminum Decking Installed
By the 1930s, the aging bridge began showing signs of wear. The increasing weight of traffic became a threat to the load-bearing capacity. In 1933, the downstream deck was rebuilt using structural aluminum beams and prefabricated aluminum decking.
This experimental use of aluminum proved to be a success. The technological breakthrough substantially reduced the weight of the bridge while providing the same level of stability as the steel and wrought iron previously in place. The use of aluminum lessened the structural load by 750 metric tons.
In addition to the vehicular lane, the supporting beams and the wooden deck on bridge's the upstream side was also replaced. The streetcar lines were subsequently rebuilt and upgraded.
Further Repairs And Renovations
Thirty-four years passed before the bridge saw any further significant changes. Then in 1967, after years of planning, the bridge underwent an extensive repair and renovation. The aging structure was showing serious signs of deterioration. Weight limits and restrictions were placed on vehicles.
The downstream roadbed was again replaced, this time with an even lighter variant of aluminum beams and decking, reducing the structural weight a further ninety metric tons. A complete overhaul of the bridge was put off, but the results were good enough to guarantee a few more decades of reliability.
In addition to the bridge repairs, the pavilion-like canopy along the southern abutment was removed. The total cost of the project was $712,000.
In 1985, after over a century as one of the main transit railway routes into the city, the Port Authority transfered all streetcar traffic from the Smithfield Street Bridge. It was rerouted onto the refurbished Pennsylvania Railroad Panhandle Bridge, which was now part of the Pittsburgh's modernized "T" light rail and system, which included a downtown subway system.
The Smithfield Street Bridge remained the primary transit route for buses along Carson Street and the Port Authority's South Busway. The next several years saw the bridge again fall into a state of disrepair while plans were drawn up for a major overhaul. By 1993, weight restrictions on vehicles had been reduced to three tons. Bus service was rerouted to other bridges.
Complete Restoration Of The Bridge
Finally, in 1994, the famous structure was closed for a complete reconstruction. The streetcar tracks were removed. The entire metal frame of the structure was repaired or replaced. The structure was strengthened with additional structural supports. The upgrades increased the bridge's load limit from three to twenty-three tons.
When the year-long renovation was completed, motor traffic was given two lanes southbound (downstream side) and a new single lane northbound (upstream). The original three-color paint scheme specified by Lindenthal was restored. Finally, the six copper finials, which had been removed from the portals due to decay, were replaced. The results were magnificent.
Today, the Smithfield Street Bridge still serves as one of Pittsburgh major arteries from the South Shore to downtown. In addition to being the city's oldest river bridge, the historic span has the distinction of being the oldest steel through-truss bridge in America, and the only one in this country employing the Pauli system of over-and-under double lenticular truss design.
Arguably the most elegant bridge in the City of Pittsburgh, the Smithfield Street Bridge was designated a National Historic Civic Engineering Landmark in 1976. It was added to the list of National Historic Landmarks in 1980.
Vintage Images Of The Smithfield Street Bridge
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