Ashley Phosphate North Charleston, South Carolina Back to Project List   Vibratory Ground Improvement Wet Vibro Concrete Columns are installed with ready-mixed concrete delivered to the project site. Conventional concrete pump delivers concrete to the tip of the vibro through a tremie tube arrangement. Project Overview: Layne utilized three different types of ground improvement techniques to provide for long term reduction in settlement, seismic retrofit and drainage in North Charleston, SC. The scope of work required ground improvement at four bridge abutment approaches where US Route 52 and Ashley Phosphate Road crossed over the highly traveled Interstate 26 going into and out of Charleston. Existing bridge approaches historically settle over time and require substantial maintenance in the form of repaving. The new bridge approach embankments were designed to resist seismic loading and to reduce post-construction settlement, as well as differential settlement between the abutment and the pile-supported bridge structures. Ground improvement techniques consisted of 400 compaction grout points, 350 vibro stone columns and 200 wet vibro concrete columns. The depth of improvement extended from the ground surface through the upper loose and soft sediments consisting of layers of sands with varying amounts of silt and clay down to the Cooper Marl. Treatment depths ranged from 28 to 42 feet.   Value of Work Performed: $960,000 Project Duration: 18 months Project Completion Date: September 2004 Project Reference: S&ME Consulting Engineers Angela Musselwhite (843) 884-0005