Location: St. Louis and St. Charles Counties, Missouri
Client: Walsh-Alberici Joint Venture
Owner: Missouri Department of Transportation
Services: Drilling, Deep Foundation Testing, Geotechnical, Non-destructive testing
The original continuous truss bridge opened in 1932 to accommodate both east and westbound traffic when the population of St. Charles County was roughly 25,000. In 1989 in an effort to accommodate increased population and vehicular traffic the original bridge was converted to two-lanes of westbound traffic only while a new continuous truss 2-lane bridge was opened to handle eastbound traffic. Additional modifications to the new eastbound bridge were then made in 2001 narrowing the lanes and removing shoulders to allow for three lanes of traffic eastbound.
From the 1980’s through the 2000’s, St. Charles County has been ranked among the fastest-growing counties in the nation and the congestion along the I-64/40 corridor between St. Charles County and St. Louis County made it abundantly clear that additional measures would have to be made to accommodate the populous.
A new girder bridge was designed in 2004 and funding was unveiled in 2011, construction for the project began
in 2013 and is scheduled for completion in 2015.
Geotechnology performed drilling and testing for foundation inspection holes within the footprint of each drilled shaft to confirm rock quality below the bearing surface of each drilled pier. Crews drilled through more than 100 feet of alluvial deposits consisting of clays, silts, sand and cobbles. Overwater drilling was performed by utilizing a skid mounted drill rig on a barge to core down to between 80 – 112 feet below the working platform. These significant lengths of unsupported casings caused bowing and twisting which added another layer of complexity to the project. Land borings were performed using truck mounted rigs owned by Geotechnology, Inc.
By the end of this portion of the project, 42 foundation inspection holes consisting of 1,950 feet of rotary drilling and 903 feet of NQ2 rock coring were completed without accident or injury.