Using a Drilled Shaft Supported Bridge for Emergency Slide Repair, US 231 near Huntsville, AL-PPT Presentation

PPT Presentation

Pdf Summary

In February 2020, a major landslide closed both directions of US 231 near Laceys Spring, Alabama, a heavily traveled route for Huntsville commuters. Detours added 30–60 minutes to journeys, making a rapid repair essential.<br /><br />The project faced severe time constraints, along with environmental and right-of-way considerations. Preliminary grading began on March 6, before bridge design was complete, to accelerate the work. About 220,000 cubic yards of material were removed before bridge construction, with further excavation required for grade beams.<br /><br />Extensive geotechnical investigation helped determine rock elevations and design the bridge foundations. Borings were performed during grading and additional borings were taken at shaft locations. ALDOT and the design team evaluated multiple foundation options, varying shaft diameters and lengths, the number of shafts, and assumptions about rock and soil strength.<br /><br />Bridge construction began June 1, and the bridge opened to traffic on September 28. The presentation also describes shaft construction methods and the installation of instrumentation, including inclinometers and vibrating-wire piezometers, to monitor ground movement. Monitoring was planned through spring 2022, alongside an action plan specifying responses if movement was detected.

Keywords

landslide

US 231

Laceys Spring

Alabama

bridge repair

geotechnical investigation

foundation design

shaft construction

inclinometers

piezometers