Engineering Wonders of the World
Volume I

THE ST. LOUIS BRIDGE 165 A Rival Scheme frustrated. operations at the other end of what, in the eye of the law, was one and the same bridge. After protracted wrangling the first-named association, sup- ported by public opinion and by the exertions of their chief engineer, whose genius touched finance as and wrought iron, rests upon two stone chan- nel piers built up solidly from bed-rock, and springs from abutments on either bank, also of masonry, and massive enough to resist the enormous outward thrust of the arches. At the position selected for the bridge, or rather, forced upon the constructors by the earlier well as his profession, finally “ swal- lowed ” their rivals, while adopting their title. Meanwhile the credit of all parties had been impaired, and even after the compromise capital was diffi- cult to raise. Again Eads came to the rescue, embodying his plans in a mas- terly and convincing report. The pub- lication of this remarkable document, reflecting the deep study and brilliant science with which the problem had been approached and finally solved, aroused world-wide interest and ap- proval among engineers and capitalists alike. The necessary funds were now obtained, and the work was pushed forward vigorously, despite the absence of the master spirit, whose health had broken down under the strain of the long negotiations. The salient feature of Eads’s design is the use of the ribbed arch, the con- struction of which will be explained when the superstruc- „ . , „ ., ture or the bridge comes Eads s Bridge. ° under consideration. The State Legislatures concerned hav- ing wisely required, in the interests of SINKING THE CAISSON OF THE EAST PIER THROUGH THE SILT. This caisson reached rock at a depth of 119 feet below nqrmal high-water mark. navigation, a minimum length of 500 feet in one at least of the spans, and the distance from bank to bank being 500 yards, the bridge is most fittingly carried over three fine sweeping arches, the centre one of 515 feet span, and rising 56 feet clear above high-water level at its crown ; the side ones each of 495 feet span, rising 51 feet. The superstructure, which, apart from the timbers immediately under the carriageway, is entirely of steel machinations of their rivals—who contrived that the approach should be from the centre of the city front, where land was dearest— the rock bed of the river slopes very steeply from the western side, and runs so deep below the eastern shore that Eads originally planned a pile-and-concrete foundation for the east abutment, at a moderate depth. Experience gained in sinking the piers led him, however, to carry the foundations here also down to