Eads Bridge

Although the bed-rock at the site of this abutment is seventy-three and a half feet higher than at the east pier, the difficulties encountered in building its foundation were of a much more perplexing and tedious character than those encountered at either of the others. Its site had been for over sixty years a part of the steamboat wharf of the city, and as such, had received every kind of useless material thrown overboard from the various steamers lying over it during that time. The old sheet iron enveloping their furnaces, worn-out grate-bars, old fire-bricks, parts of smokestacks, stone-coal cinders and clinkers, and every manner of things entering into the construction of a Mississippi steamer, seemed to have found a resting place at this spot, and constituted a deposit averaging twelve feet in depth over the rock.

During the memorable fire of 1849, when twenty-nine steamers were destroyed at the levee, the wrecks of two of them sank upon the site of this abutment. One of these was partly covered by the hull of the other, which probably sunk immediately afterwards. The lower one was but two or three feet above the bed-rock. After this terrible conflagration, the city authorities determined to widen the wharf. Its front was extended to a line enclosing about one-half of these two wrecks, by filling in with the stone and rubbish of the city. During this extension, several other vessels were burnt at the wharf, and the wreck of one of these also sunk upon the site of the abutment. The coffer-dam, constructed to inclose [sic] the site, had to be put down through these three wrecks, the hulk of either of which was not probably less than four hundred tons measurement. Their bottom planking was all of oak, three or four inches in thickness. To drive the sheet-piling down through these hulks, an oak beam, six by ten inches square, armed with a huge steel chisel, was first driven down as far as a steam pile-driver could force it. It was then withdrawn and a sheet-pile, five by ten inches square, was driven in its place. The coffer-dam was formed of two courses of sheet piling, six feet apart, which were filled in between with clay. When this was completed, the water pumped out and the excavation prosecuted within it, the discovery was made that from one-third to one-half of the length of each of these three steamboat hulks was inclosed [sic] within the dam, and that some of the sheet piling had not been driven through the lower one, owing to the great resistance of the hulk and the mass above it.

Before the space between the lower wreck and the bed-rock could be made secure on the inner side of the dam, the water came through and flooded the enclosure. A stream from a powerful Gwynne pump, having an eight-inch diameter of jet, was then directed against the material deposited over these wrecks on the outer side of the dam, where the water was fifteen feet deep, and enough of the deposit was washed away to enable another course of sheet-piling to be driven down six feet beyond the dam, through all of the wrecks, to the rock. After this, that part of the wrecks inclosed between this last course of piling and the dam, was removed by a diver and the space filled in with clay, and the inclosure [sic] again pumped out. This portion of the dam, about fifty feet in length, was by this construction made double.

As the excavation within progressed, it revealed the fact that another portion of the dam had been built and made water-tight through and over a water-wheel of one of the wrecks. The crank of an engine of seven feet stroke, attached to the head of the shaft of the wheel, was just within the inclosure while the flanges, arms and braces of the wheel were within the walls formed by the sheet piling. From the inclosure within the dam were taken parts of several old and burnt steamboat engines, the iron parts of some of which had been cut off at the dam. Four wrecks of barges, some of them in use doubtless before the era of steam, were also found within it; likewise several oak sawlogs, some anchors, chains, and a great variety of smaller articles lost or thrown overboard from the river craft, or dumped in from the city.

This incongruous deposit made it exceedingly difficult to maintain the integrity of the dam, which at times had to resist a pressure of thirty feet of water. Frequent floodings consequently occurred, which delayed and increased the cost of the work. These difficulties were however, finally overcome, and the bed-rock within was at last exposed to view.