MacArthur Bridge Approach Viaduct (West)

View an article discussing the construction of this viaduct

During the 1890s, the Terminal Railroad Association of St. Louis was growing in power, owning both the Merchants Bridge and the Eads Bridge, the only crossings of the Mississippi River at St. Louis. Because the TRRA owned both bridges, the TRRA could set tariff rates for freight and passengers crossing the Mississippi River at St. Louis. During the early 20th Century, the City of St. Louis desired a "free bridge", which would provide toll free passage of railroad and roadway traffic across the Mississippi River. A Municipal Bridge Commission was formed in 1905 by the Mayor Rolla Wells to study and construct a toll-free crossing of the Mississippi River. A bond issue was voted on in 1906, authorizing money to construct the bridge.

In 1908, acquisition would begin on the right-of-way for the bridge. After a rejected design, it was decided to construct the main bridge with three large main spans, with a double track railroad deck on the lower portion of the bridge and a roadway portion on an upper deck. A series of viaducts would need to be constructed to the bridge to allow railroad and roadway traffic to use the main spans. The viaducts would be designed by Boller, Hodge and Baird. The main bridge would utilize three large through truss spans to cross the Mississippi River near Chouteau Avenue. With a 677-foot main span, these spans were the highest, longest and heaviest constructed at the time. Construction on the main bridge was started in late 1909, and completed in 1912. The American Bridge Company was contracted to provide the steel for the bridge, with the Missouri Valley Bridge & Iron Company constructing the main stone piers. Until approach viaducts could be constructed, the bridge could only be utilized by pedestrians, which had to climb stairs at either end and utilize a wooden deck on the railroad deck to cross the river.

After much discussion regarding the location of the west approach, a contract for the superstructure of the combined roadway and railroad portion of the viaduct, as well as the separate roadway portion, would be awarded to American Bridge Company in August 1911. Missouri Valley Bridge & Iron Company was awarded the contract for the substructures of this viaduct at the same time. In September 1912, two separate contracts for the superstructure and the substructure of the separate railroad portion of the viaduct would be awarded to American Bridge Company and Fruin-Colnon Contracting Company, respectively. Construction of the viaduct was begun in 1911, with the roadway portion opening in April 1913. The railroad viaduct was completed soon after. The eastern approaches would not be completed until 1917. Due to disagreements between the City of St. Louis and the various railroads, the railroad deck would not be used until 1928, when the southwest approach viaduct would be constructed.

The west approach mainly consisted of deck plate girders, with truss spans located immediately west of the main span and across Broadway. The deck girder spans would be set onto steel towers, steel bents and concrete pedestals. The concrete pedestals were constructed on concrete piles, which were driven to solid bedrock. The clear deck girder spans of the viaduct would vary in length, with many of the tower spans constructed of 45-foot spans. The railroad portion of the viaduct utilized two curves; one near 3rd Street and the other where the separate roadway viaduct diverged near Broadway. The railroad portion of the viaduct would connect to the St. Louis Terminal Railway yard, and the roadway viaduct would connect to 7th Street north of Chouteau Avenue. The roadway deck would utilize concrete, cast into metal pans. Like the remainder of the roadway portion of the bridge, streetcar tracks would be installed along the roadway viaduct. The cost of the viaduct would be $552,427, with 7,938 tons of steel used in the viaduct.

The west approach viaduct would begin at pier #1, the west end of the main bridge. Here, the roadway deck would be located over the railroad deck. A 155-foot, 6-panel riveted Pratt through truss span would be used for the roadway deck immediately west of the west main truss, with a 45-foot and a 70-foot deck plate girder span shifting the roadway deck to an alignment adjacent and above the railroad deck. Underneath the roadway spans, the railroad deck utilized a 79-foot, a 60-foot and a 45-foot deck plate girder span. The parallel viaducts then shared steel towers, crossing a TRRA line, 1st Street and Risley Street, before reaching the same grade near 2nd Street. The viaduct would then continue across 3rd Street, crossing 4th Street with a 90-foot deck plate girder span, the heaviest of the entire structure. Between 4th Street and Broadway, a passenger station would be installed between the two tracks. Across Broadway, the roadway portion of the viaduct utilized a 105-foot, 6-panel riveted Pratt through truss span, while the railroad portion used a 125-foot, 7-panel riveted single track Pratt through truss span. The southern railroad track would be supported between the two separate trusses. Immediately west of Broadway, the viaduct would diverge. The roadway portion continued west, before ending across 6th Street. The railroad portion would continue, crossing 6th Street and 7th Street, before ending at 7th Street near Gratoit Street.

The deck plate girder viaduct design was the most popular design for long viaducts, as it provided the best economy and strength. These types of structures were extremely adept to curves, steep grades and tight spaces. Several of the railroad deck girder spans would utilize a "fishbelly" design, where the centers of the span would be deeper than the ends. This was done to accommodate larger clear spans, without changing the tower designs. The truss spans across Broadway utilized heavier variations of the Pratt design, which was popular during the late 19th Century. The railroad span utilized solid members, a solid portal bracing and a heavy floor. The roadway portion would use a similar design, with a lattice portal. The 155-foot approach span to the main bridge would use a lighter span of similar design to the Broadway span. Towers #2, #3 and #4 (using bents #W3-W8) would utilize a design which allowed for maximum clearance underneath, to accommodate a yard of the TRRA.

Since the initial construction, this approach viaduct has seen several changes. A southwest viaduct was added in 1928, which left the approach viaduct near the main spans. From 1929 until the completion of the Poplar Street Bridge in 1955, the bridge would carry the famed US Highway 66. In 1942, the bridge was renamed from the Municipal Bridge to the MacArthur Bridge in honor of General Douglas MacArthur. In approximately 1955, three spans across 3rd Street were replaced with two 100-foot deck plate girder spans, set onto concrete piers, as part of the construction of Interstate 44 and Interstate 55. Due to the heavy use of the bridge, the roadway deck would gradually grow into disrepair. After the completion of the additional railroad viaducts, railroad traffic steadily increased on the bridge. By 1981, the bridge would be closed to automobile traffic, and portions of the eastern roadway approach removed. The bridge would be given to the Terminal Railroad Association in 1989 as part of a swap, with St. Louis acquiring the Eads Bridge.

The roadway viaduct had sat unused since 1981, posing a hazard to the public below. Removal of the concrete deck of the roadway viaduct would begin in 2014, with the removal of the 155-foot truss in 2015. In 2022, the TRRA decided to rehabilitate the west approach. As part of the rehabilitation, the truss span over Broadway would be replaced with a modern deck girder span, set onto new concrete piers. In addition, the entire roadway viaduct would be removed. This work was completed throughout 2022, giving the viaduct its current appearance. Due to the age of the viaduct, it is likely that more work will be required in the near future to keep the viaduct operational. Overall, the viaduct appears to be in fair condition, with some deterioration seen throughout the structure at various points. Several towers and spans have been strengthened, mainly by replacing members and rivets. The author has ranked this structure as being regionally significant, due to the length, history, unique spans and relation to the main bridge.