I-270 over Chain of Rocks Canal

Summary

Kaskaskia Engineering Group, LLC (KEG) provided geotechnical and transportation services for the I-270 Bridge over the Chain of Rocks Canal project in Madison County, Illinois. KEG was an integral part of the development of the geometrics for the proposed alignment of I-270, as well as the partial reconstruction of the interchange between I-270 and IL Route 3.    

Project

KEG prepared the structure geotechnical report for the proposed structure.  KEG was responsible for the design and implementation of the subsurface exploration plan, which included SPT borings and NX rock cores.  KEG was also responsible for the laboratory testing assignments.  In addition to the water-based soil borings, cone penetration tests were performed to delineate the soil stratigraphy between the SPT borings, allowing for a more precise picture of the geotechnical engineering properties present.  Forensic RAPID CPT software, in conjunction with gINT V8i, was used to manage and interpret the field data.  gINT V8i databases were also utilized to create the soil boring logs and soil profiles for the SGR.  KEG was also responsible for the geotechnical design and analysis of the proposed structure, which included the design of the drilled shaft foundations.  The deep foundation design included plan drawings and construction specifications. Other geotechnical analyses included levee construction, retaining walls, and liquefaction analysis.  These analyses were used to prepare preliminary client reports and the final SGR.

Early in the planning stages, KEG was part of the “design charrette”, which was composed of project team members from HDR, KEG, and IDOT.  The purpose of the design charrette was to discuss the advantages of the seven preliminary bridge-type designs and the alignments and evaluate each separately for their unique advantages.  KEG assisted HDR in performing a peer review of the short-listed alignments that were developed from the design charrette.

In addition to the geometric tasks, KEG was also responsible for the development of the crash report for the study area.  By utilizing GIS crash data, KEG developed a comprehensive report that not only included the injury and fatality crashes, but also the property-damage-only crashes that occurred along I-270 and the interchange during the 5-year study period.  The crash analysis report was approved by IDOT in 2010.

KEG also prepared the Interchange Design Study (IDS) for the existing interchange between I-270 and IL Route 3 which included partial reconstruction of the interchange, including realignment and removal of existing ramps.  KEG worked closely with HDR and IDOT during the preparation of the IDS due to the aggressive project schedule.  The IDS was approved by IDOT in 2010.