I-70 FROM IL-203 TO RELOCATED IL-3
CONSTRUCTION COST: $24,000,000
COMPLETION DATE: N/A
CLIENT: ILLINOIS DEPARTMENT OF TRANSPORTATION

As part of a project to construct a new Mississippi River Bridge into downtown St. Louis, Oates Associates is designing a 1.1 mile section of relocated I-70 between IL-203 and relocated IL-3.  The design includes two interchanges, six-lane mainline pavement plus 9 new bridge structures and retaining walls. 

The Mississippi River Bridge project is being managed for the Illinois Department of Transportation by a Project Management Consultant (PMC).  The PMC is responsible for coordinating the work of several design consultants, including Oates Associates, and performing work on corridor-wide design components such as land survey, lighting, signing, aesthetic treatments, etc.  This project management arrangement has required an administrative structure and reporting not normally found in IDOT design projects. 

Phase I location / design report and survey files were provided by the client, with supplemental topographic survey and staking performed by in house staff.  Construction plans are to be prepared for 9 separate construction sections. 

Eight bridge structures and two new retaining walls will be designed in this project.  The scope includes structure reports, T S  & L Drawings, preliminary and final plans.  Seismic analysis of structure design is necessary due to project location in seismic performance category B.  Due to anticipated poor soil conditions, complex geotechnical engineering is required for foundation designs and roadway fill.  Geotechnical work was performed by a subconsultant.

Roadway design includes design of 6-lane mainline pavement, interchanges at IL-203 and IL-3, maintenance of traffic at IL-203, traffic signal plans at that location and staging coordinated with other design sections.  Drainage design includes plans for detention and compensatory storage.