INTERRA was selected by Patrick Engineering to perform work for this IDOT project which included the construction of a three-span bridge, 10 retaining walls, 15 box culverts, the addition of one lane in each direction, and the replacement of traffic signals for nearly a seven mile stretch of IL 31 between IL 120 and IL 176. INTERRA performed geotechnical services which included nearly 250 soil borings totaling 5,000 feet of drilling. Field services included collecting split spoon samples, Shelby tube samples, bulk sampling for further laboratory testing, and the classification of soil. INTERRA installed piezometers to determine groundwater levels. The scope of work also included performing infiltration testing. Laboratory work consisted of moisture content, grainsize analysis, Atterberg limits, organic content, and Proctor testing. Structure Geotechnical Reports (SGR) were prepared for bridges, retaining walls, and culverts. Roadway Geotechnical Reports (RGR) were also prepared for additional lanes and traffic signals.
