A column supported embankment design method was selected for the approach embankment design.  In this design, 18″ diameter concrete columns will be spaced 8 feet center-to-center for the first 106 feet (starting at the bridge abutment).  After the first 106 feet, the spacing of the concrete columns increases to 10 feet center-to-center until the end of the approach.  The load transfer platform used in this design will be 3.25 ft thick.  The load transfer platform is used to distribute the load of the embankment to the columns below.  Additionally, Tensar Biaxial Geogrid BX1500 was selected as a reinforcement layer between the load transfer platform and the top of the concrete columns.  This reinforcement is necessary to prevent the columns from punching through the fill of the embankment.  Each approach embankment will require 105 18″ concrete columns and 7632 sq. feet of geogrid reinforcement.