Recently, apropos to nothing, a major collector of rare manuscripts claimed that the St. Louis region lacks major collections of historic documents. A more inaccurate statement about the rich resources in our city could not be made. In particular, I learned earlier this year that the holdings at the Washington University Libraries contain some of the most critically important primary source documents from American architecture. From James Eads to William Bernoudy, the Special Collections give historians new perspectives on the great architectural achievements of the last 150 years. Last spring, Miranda Rectenwald, Curator of Local History Archives & Special Collections, allowed me to examine the university’s folder of Eads Bridge-related drawings and blueprints. The experience was revelatory.
Being able to view the documents in person, and not merely through digital files, revealed the incredible artistry and ingenuity of the self-taught engineer James Eads, and perhaps his most famous legacy, the bridge in downtown St. Louis. A man or woman such as Eads would never be allowed to succeed in modern America. The idea of an engineer teaching himself would be impossible; there are countless exams, degrees and certifications that Eads, even perhaps after completing all of his engineering feats, would still not be able to pass. But the young inventor seemed to adapt to his surroundings in mid-19th century. His early invention, a diving bell that allowed for the salvaging of merchandise from sunken riverboats, was a perfect and timely invention when those accident-prone craft dominated St. Louis’s economy. Likewise, arriving at the perfect moment, Eads’s ironclads, built in Carondelet, helped the Union seize control of the Mississippi River during the Civil War.
So after the Civil War, when St. Louis leaders finally and belatedly got around to building a railroad bridge across the river, Eads proved to be at the right place at the right moment yet again. Never having actually designed a bridge of any length before, he managed to leverage his reputation to secure the contract. Much has been written before about why the Eads Bridge proved so revolutionary, but to summarize, there were a couple of major reasons. First and foremost, the bridge made use of steel in amounts never seen before in a major structure of its type. Secondly, it utilized caissons to plunge through the deep mud of the river to secure the piers to bedrock. Finally, the use of cantilever structures, rising high above the stone piers in the river and abutments on land, kept the river channel open to riverboat traffic throughout construction. But examination of the original—and some later—drawings in the Eads Bridge collection at Washington University reveal some interesting surprises not normally included in the bridge’s legendary story.
First off, to the west of the bridge in the tunnel that still snakes through downtown, builders constructed a towering smokestack that ventilated the smoke from the coal-powered steam engines. One diagram shows how the stack featured a giant fan that would have pulled smoke out of the middle of the tunnel. While most of the tunnel traveled under the right-of-way of city streets, another map shows the various property owners that the tunnel builders would have to approach in order to secure permission to cross their land as the tunnel curved from north-south to east-west. As far as can be ascertained, the tunnel was constructed under pre-existing buildings that were not demolished. Diagrams show the steel framework that supported the massive, now lost, smokestack.
Meanwhile, on the bridge itself, Eads was also designing the massive stone piers and approaches that held up the revolutionary steel bridge spans. It’s interesting to see how much thought the engineer put into the piers, considering that most of the attention goes to the use of steel in the bridge. For example, Eads prepared at least three different decorative styles for the piers; one shows a more classical emphasis, with Tuscan pilasters, while another design shows a more severe, modern form. One option almost looks Egyptian Revival in style. Ultimately, the simple design won out in the end. But nonetheless, diagrams survive that would have shown stonecutters and masons exactly how to produce the stone for the piers, each illustrated with care on a large sheet of paper. Up above on the roadway, Eads even designed the lampposts and balustrade, carefully reproduced in the recent renovation of the bridge.
Another drawing, by an unknown hand, creates a mystery. While Eads famously constructed the steel arches with cantilevered supports, thus never requiring falsework or temporary support structures below, a drawing shows how such structures would have been constructed. The drawing shows a boat directly below the middle of the arch, anchored with chains down to the riverbed to prevent capsizing. Above, a wood tower is shown holding up the steel arch. Photographs show that such a boat was not needed, and never used, but this mysterious lacuna shows that the builders did consider it long enough to include it in a drawing. How serious the idea was will probably never be known, particularly since riverboat captains had insisted the river channel stay open to traffic.
But perhaps the most stunning diagrams from Eads’s papers revolve around the sinking of the giant bridge piers deep into the mud of the Mississippi River. Eads had learned of the use of caissons before attempting them in St. Louis, and to this day his are some of the deepest ever achieved for the construction of bridge piers. Caissons are giant boxes, so to speak, that are floated out to the location of future bridge piers. The caissons are dropped into the mud, and then, once secured, workers began the construction of the bridge piers on top. But obviously the mud is not an acceptable building surface, so a high-pressure chamber under the bridge pier is created, where workers, being paid double the rate of their above-water companions, excavated out the mud of the river, slowly allowing the bridge pier to sink down to bedrock. It was unbelievably dangerous work, and at least 16 men died of “The Bends” when they left the pressurized chambers under the piers too quickly, killed by nitrogen bubbles in their blood.
Logically, one does not simply start building bridge piers without first checking on conditions and predicting the depth the piers would need to go. After all, stone must be purchased, and budgets for workers’ pay must be determined beforehand. And that leads me to the truly amazing drawing, possibly by Eads’ own hand, which shows a cross-section of the river at St. Louis. Roughly calculating the depth of the water and mud based on a key handwritten on the side of the diagram, we determined that Eads and his men had to excavate through close to 80 feet of thick mud before hitting bedrock. I can only imagine the intense heat, brutal humidity and backbreaking work that these men faced day after day, even as many of their comrades died painfully around them. And imagine the day when, instead of mud, a worker’s shovel struck bedrock, and the completion of their herculean task had finally arrived.
See Also: Like a Bridge Over Muddy Water
Chris Naffziger writes about architecture at St. Louis Patina. Contact him via email at [email protected].
