PennDOT's District 12 in southwestern Pennsylvania looks for ways to deploy Expanded Polystyrene (EPS) Geofoam, a rapid embankment construction technique used in Accelerated Bridge Construction.
This innovation, championed by the Pennsylvania State Transportation Innovation Council (STIC), involves the use of a lightweight, rigid foam plastic in place of traditional embankment or back-fill materials. It is much lighter than traditional materials and can be used to reduce ground settlement, ground instability, or lateral pressures exerted by the fill.
"We look for opportunities to use it where it's effective, cost beneficial, and makes sense," said Roy Painter, P.E., the district's geotechnical engineer. "It reduces stresses on underlying soils and increases the stability of the embankments against failure."
The technology was used for a project on Pennsylvania Route 217 to protect the existing bridge and piers against settlement during construction of a new bridge and embankments. It was also used in two locations on U.S. Route 119 in Fayette County, for a gabion wall settled backfill leveling and for cross-pipe settled backfill leveling.
The benefits include accelerated foundation construction, which reduces project schedules; reduced need for labor in construction; little to no lateral load on retaining structures; and it can be constructed easily in limited rights-of-way.
"If you have to be in the right of way, it can work better," Painter noted. "Also, it does not take as much time for the bank to settle."
Read about other recent innovations at PennDOT.gov/STIC.