The first bridge built connecting downtown St. Louis and southwestern Illinois in more than 40 years, the completely new alignment relieved the Poplar Street Bridge (PSB), which is one of only two bridges in the U.S. to carry three interstates. By shifting I-70 from the PSB to the new Mississippi River Bridge, traffic congestion has been significantly relieved.
Foundation work is always challenging in the deep, swift water of the Mississippi River. The conditions at the site are subject to flooding with a difficult current. By using proven means and methods and adapting the owner’s design to fit particular tools and equipment currently in hand, construction of the 12 drilled shafts on the new Mississippi River Bridge proceeded as planned.
Another challenging element of the bridge construction is the towers, which are 400 feet above the river. Having the experience and equipment to build towers of such height was crucial.
The project entailed construction of a 1,500-foot main span with 400-foot towers. The total length of the improvement was 1.22 miles. The work included 12 drilled shafts (11 feet, six inches); 38,225 cubic yards of substructure concrete; 9,446 cubic yards of superstructure concrete (pre-stressed slab panels); 8,188 tons of fabricated structural steel; 1,257 tons of stay cable strand; and 7,563 tons of reinforcing steel.