Eads Bridge

View the Historic American Engineering Record documentation for this bridge

View an article commemorating 50 years of service for this bridge

Throughout the mid 20th Century, St. Louis grew considerably, largely due to the location along the Mississippi River. Steamboat traffic utilized the river to connect industries in St. Louis to the Gulf of Mexico. As early as 1836, plans had been made for a railroad line extending west from the Mississippi River town of St. Louis, although construction would not commence until 1851. Prior to and during the Civil War, eastern railroads were seeking the best place to connect to western railroads. While St. Louis would become a respectable railroad hub, Chicago would soon grow into the premiere railroad hub in the United States. After the Civil War, St. Louis continued to grow, but lacked a bridge across the Mississippi River to connect to established railroads in Illinois. The need for a bridge became a pressing issue for the city, as other railroad crossings of the Mississippi River had been completed during the 1850s and 1860s further upstream, further threatening the status of St. Louis as a major city.

While ferry service had crossed the Mississippi River since the late 1790s, a permanent bridge would provide a more reliable crossing of the Mississippi River. The first proposals for a bridge at St. Louis had been made starting in 1839, but were rejected due to the cost and impracticality of the design. By 1865, the city was becoming more anxious to construct a bridge across the river, and a proposal for a tubular arch bridge, set 22 feet above the river, was made by the City Engineer. The St. Louis and Illinois Bridge Company received charters for a bridge in both Missouri and Illinois between 1864 and 1865, and the charter was met with strong opposition from the Wiggins Ferry Company, which had a monopoly on Mississippi River crossings at St. Louis. A Federal Charter was granted in 1866, and required the bridge to have a minimum 500-foot opening, with the remaining spans having minimum 300-foot openings. James Buchanan Eads was selected as the Chief Engineer in 1867, and he soon presented a design for the bridge. The design presented by Eads utilized three metal deck arch spans, each over 500 feet in length, set onto stone piers founded on bedrock.

James Eads was born in rural Indiana in 1820, and had exhibited ingenuity for designing things since an early age. After the Eads family had moved to St. Louis in 1833, Eads worked selling apples from a cart. The merchant he worked for quickly realized his gift of mechanical ingenuity, and gave him a book related to mechanical engineering. Eads would join a steamboat crew in 1839, where he worked for three years. During this time, Eads developed an understanding of the Mississippi River, and began to appreciate the possible scrap value of shipwrecks along the Mississippi River. At the age of 22, Eads began a scrapping company, where he designed his own equipment for diving and salvage operations. Throughout the 1840s and 1850s, Eads owned a profitable scrapping business. During the Civil War, Eads advocated for the use of iron clad gunboats, which would patrol the Mississippi River. Eads received Union Army contracts for constructing such boats, and made significant improvements to the weaponry systems on the boats. After the construction of this bridge, Eads worked on several more prominent engineering projects, and became a renowned engineer.

The bridge would be designed to carry two decks. A roadway deck would be constructed for the top deck, with two railroad tracks using the lower deck. The substructures of the bridge would be constructed of iron caissons, driven to reach bedrock. The caissons would be constructed using salvaged plates from the USS Milwaukee, which Eads had salvaged. The stonework for the bridge would be constructed from limestone quarried at Grafton, Illinois; with granite to face the structures quarried at Portland, Maine, Richmond, Virginia and later Missouri. The main spans of the bridge would utilized a steel ribbed arch design, with steel tubes and pinned connections supporting the structure. At the time of construction, these spans were more than 200 feet longer than any ever constructed. The superstructure of the approaches several stone arches, with a long parapet wall on the west approach. A stone and brick arcade would support the upper deck of the bridge. The roadway of the upper deck was constructed using timber beams and iron girders, set onto the arcades. The east approach viaduct would be constructed of iron girder and truss spans, set onto Phoenix Columns. During conferences with prominent European engineers, the design presented by Eads was frowned upon, but the use of compressed air to lower the caissons was encouraged by the engineers. The location chosen for the bridge would require the deepest caissons ever sunk, with the bedrock at the east pier 136 feet below the water surface.

After $300,000 in subscriptions were raised by the Bridge Company, construction on the bridge began in August 1867. James Andrews of Pittsburgh received the contract for all construction of the masonry substructure and approaches. A rival company, the Illinois and St. Louis Bridge Company, headed by prominent Chicago engineer Lucius Boomer, attempted to sabotage the efforts of Eads and the original Bridge Company. Boomer called together a group of prominent engineers to discredit the metal arch design, running newspaper ads to undermine public confidence in the company. The two companies reluctantly merged in 1868, with Eads again elected as Chief Engineer. Due to the sabotage efforts of the other Bridge Company, subscriptions had dwindled, and work ground to a halt. Eads published an article attempting to restore public confidence in the structure, and was rewarded with an offer of $4,000,000 in City of St. Louis bonds to construct the bridge. Afraid of losing the bridge should financial difficulties continue, the Bridge Company instead utilized private investments to continue construction. Construction resumed in May 1868

Early work on the bridge had much turmoil, with significant difficulties encountered during construction. A wrecked steamboat, located near the west approach, resulted in difficulty constructing a watertight cofferdam. Despite the challenges, initial stonework would be laid on bedrock in February 1868. Eads became sick with Bronchitis in July of that year, and attempted to resign his position. His resignation was rejected, and Eads took an extended leave from the construction of the bridge. While work continued, it was done at a much slower pace than with Eads present. Work was again stopped in September 1868, but $25,000 was received to bring the west pier above high water, which was completed in early 1869. Bankers in New York and London refused to advance any additional funding before the bridge piers topped high water. Additional funding was secured to complete this work, and by June 1869, Eads returned to the job, with work resuming at full pace. By the end of 1870, all caissons had been sunk, and the piers had been nearly completed.

The depths required for the caissons proved to be dangerous work. Caisson sickness, also referred to as "the bends", was a severe side effect of working in a high pressure caisson. Other bridges had been constructed in a similar manner, with laborers exposed to pressures up to 3 times atmospheric pressure. Due to the immense depth of the caissons on the bridge, several laborers developed caisson sickness. Of the approximately 600 men who worked under compression in the caissons, 100 showed slight sickness, 119 others required medical attention, 30 had serious side effects, 2 were paralyzed for life, and 14 died. Because of precautions learned at the other piers, only one death occurred during the construction of the east pier, which required the deepest caissons.

In February 1870, the contract for the superstructure of the bridge was awarded to Keystone Bridge Company. Owned by industrial tycoon Andrew Carnegie, the company was the leading bridge construction firm at the time. As part of the specifications, considerable testing would be required on all components, which utilized a grade of metal not commonly used during the time. Several grades of iron and steel were ultimately decided for the bridge. While steel would become the dominant bridge building material by the late 19th Century, it had not been used extensively prior to the construction of this bridge. The envelopes or outer tube plates for the arches would be fabricated of chrome steel, with the interior staves using homogeneous steel. Due to several changes in materials specifications, relatively little of the original contract price for the bridge would be honored, and significant change orders were required. Delays in determining and accepting materials led to an extension on the original completion date of the contract.

Throughout 1873, much of the superstructure of the main spans would be erected. The arch spans were erected in a cantilever method, which reduced the amount of falsework required and interruption to river traffic. Wooden towers were erected on the stone piers, which allowed for the construction of the main spans. As the arches were being constructed, court filings were made by the steamboat lobby due to the illusion of a lower height across the river. At a hearing in September 1873, the bridge was determined to be a hazard, and it was ordered that a drawspan be installed at the east end of the bridge, at great cost to the Bridge Company. The matter was later dropped when President Ulysses S. Grant told his Cabinet Appointee to drop the matter, allowing the bridge to be constructed as planned. During the erection of the west span, severe distortion was found to have been caused by heat. Despite extensive use of ice to counteract the thermal expansion of the steel, the problem continued. Assistant Engineer Henry Flad decided to use Eads recommended solution of cutting a portion of the tube, and joining the structure by use of a wrought iron plug. In January 1874, inspector Theodore Cooper found two cracked tubes. Replacement tubes would be ordered, and no additional material issues were discovered during construction. By April 1874, the bridge and approaches were ready to open to roadway and pedestrian traffic. Due to outstanding debt, the Keystone Bridge Company removed planks on the roadway deck, preventing the opening of the bridge. After negotiations, the bridge was allowed to open to traffic. The roadway deck opened to traffic on May 24th, 1874; with the first train crossing the railroad deck on June 9th. The bridge was officially dedicated on July 4th, 1874; with an elaborate celebration of parades, speeches and fireworks. Originally known as the St. Louis Bridge, the bridge would become known as the Eads Bridge relatively soon after completion. It is believed that this is one of the only bridges in the world named for its designer. The total cost of the bridge would exceed $7,000,000; an astronomical cost at the time.

As initially constructed, the bridge consisted of a 520-foot and two 502-foot ribbed steel deck arch main spans. Ribbed arches utilize parallel arch lines, connected by members to retain a rigid shape. The spans of the Eads Bridge utilized four parallel arch lines, which were constructed of two steel tubes. These steel tubes were constructed in 40 segments, and used pinned connections to connect to the remaining members of the structure. The tubes would be constructed quarter inch thick steel plates, and would be 18 inches in diameter, connected to other segments by couplings. The tubes would be filled with rods known as staves, which provide much of the strength of the arch lines. The members between the arch lines, as well as connecting to the upper deck, utilizes a v-laced design, typical for early bridges. The original railroad floor inside the arch was constructed of steel plate girders, a typical design for the era. The roadway deck was originally supported by wooden planks.

The west approach of the bridge originally utilized a lengthy stone and iron approach. Five stone arches of 27 feet each would be located immediately west of the main spans, with a sixth span of the same design crossing an alleyway east of 1st Street. 45-foot through plate girder spans were installed at 1st and 2nd Streets, and were set onto stone abutments. The original spans at these locations utilized iron hangers, which helped to support the roadway deck above. A 30-foot span of a similar design crossed an alley between 1st and 2nd Streets. The remainder of the structure would consist of stone parapet walls, filled with earth, which supported the lower railroad deck. On top of these parapet walls, stone and brick arcades of smaller arches formed the outer walls of the upper deck, with the upper deck originally supported on timber beams and iron stringers. Faux arches, where the arch ring was present in the parapet wall without forming an opening, were utilized east of 1st Street as a decorative feature. At the west end of the bridge, the railroad descends into a tunnel, while the roadway descends to street level. Towers located at the end of the approach supported a tollbooth, and were added to provide aesthetic value to the bridge. The east approach of the bridge originally utilized a similar design, with a lengthy iron approach viaduct. Immediately approaching the main spans, the bridge used five stone arch spans of 27 feet, with a stone arcade wall above. Similar to the west approach, towers were installed on the bridge, which were smaller than the original design called for. The remainder of the approach consisted of iron deck girders and deck trusses, set onto Phoenix Columns.

While the bridge provided an important connection for railroad and roadway traffic, it never lived up to its full potential. The location of the bridge proved to be difficult for railroads to access, and the tunnel on the west side provided operational and safety hazards for train crews and passengers. By April 1875, the bridge would be sold for $2,000,000 to the St. Louis Bridge Company, which was formed from the same investors of the previous company. In 1877, the bridge would be purchased by the Terminal Railroad Association of St. Louis (TRRA), and the bridge became the keystone component of the TRRA system. The TRRA was incorporated to control interchanging between the several railroads which met at St. Louis and East St. Louis. The opening of the Merchants Bridge in 1890 reduced the demand for railroad traffic crossing this bridge, and the opening of the MacArthur Bridge in 1928 further reduced railroad use of the bridge.

Since the initial construction of the bridge, the bridge has seen several changes. Between 1894 and 1896, the entire east approach would be reconstructed with new deck truss and deck girder spans, set onto traditional steel bents and towers. The replacement of the approach allowed for a streetcar to begin using the upper deck. The deck truss spans would consist of modified pin-connected Baltimore deck truss spans. Also in 1896, a tornado severely damaged the east approach arcade of the bridge, which would be replaced with a different stonework. In 1903, the bridge would be upgraded, with the approach spans across 1st Street, 2nd Street and the alley replaced with new spans of the same size. In addition, several spans would be upgraded on the east approach, with through girder spans installed. In addition, the railroad deck across the main spans would be replaced by a new deck of similar design. This work would be completed by the Massillon Bridge Company. In approximately 1920, the arch span across the elevated Terminal Railroad Association tracks would be replaced with a 30-foot deck girder span, to allow for greater clearance below. This span would be set onto the original stone substructures, which were modified with concrete. This span utilized several parallel lightweight girders, which may have been reused here from another location.

In 1922, the roadway deck on the eastern approach was reconstructed with a concrete frame design, which reused the original arcade walls. As part of this work, a concrete wall was constructed along the middle of the structure, and a concrete roadway deck added. Several of the arcade walls would be closed with bricks, concrete or stone, likely to provide greater strength for the roadway deck. At the cross streets, roadway deck would rest on new concrete frames, which spanned the entire opening. The roadway deck across the main spans was reconstructed in 1946, using a concrete design to replace the original wood plank deck. Numerous other repairs were made to the bridge at varying times, which included various masonry repairs, strengthening of the main spans, repairs to the east approach viaduct, and other miscellaneous repairs. Contracts were let to Stupp Brothers Bridge & Iron Company in 1917 for 120 tons of steel for repairing the bridge, and to the Mississippi Valley Steel & Iron Company in 1924 for 342 tons of steel for repairs.

By the early 1970s, the bridge had begun to show its age. Dimensions of modern railroad equipment were too great for the Eads Bridge, and the MacArthur Bridge had become the preferred crossing of the Mississippi River. The last train crossed the bridge in 1974, and the rails over the bridge were removed. During the 1980s, plans were made for repairing the bridge and reusing the structure as part of a Light Rail project, now known as Metrolink. In 1989, the City of St. Louis swapped the Eads Bridge for the MacArthur Bridge with the TRRA in preparation for this project. The railroad deck was then given to the Bi-State Development Agency to construct the light rail. From 1989 until 1993, the bridge was extensively rehabilitated. In 1993, the bridge opened to MetroLink traffic, which it continues to carry. As part of this rehabilitation, the entire east approach structure was replaced with modern girder spans, and the spans across 1st Street, 2nd Street and the alleyway were also replaced with modern spans. As part of this rehabilitation, the towers were removed, except for the southwestern tower. In addition, the floor of the railroad deck was replaced with modern steel stringer spans. In 2003, the roadway deck of the bridge was reconstructed and reopened to four lanes of automobile traffic. Several segments of arcade wall on the west approach were replaced with concrete at this time. Further rehabilitation were made between 2012 and 2016, when significant portions of the masonry approaches were repaired. The last rehabilitation is expected to greatly extend the life of the historic bridge.

Despite the numerous alterations to the structure, the bridge remains one of the most significant bridges in the United States. In addition to being listed on the National Register of Historic Places, the bridge was designated as a National Historical Landmark in 1964. Over 150 years after opening, the controversial design chosen by Eads continues to safely carries traffic across the Mississippi River. The bridge has been repeatedly described in engineering literature as one of the finest bridges ever completed in the world. Overall, the bridge appears to be in good condition, with no significant deterioration noted. The author has ranked this bridge as being nationally significant, due to the unusual design, old age and unique history.