I-84 Burley and Heyburn Interchanges

CLIENT Idaho Transportation Department (ITD)

Location Minidoka County, ID

The I-84 Burley-Heyburn Interchange project is being constructed to accommodate the anticipated traffic growth increase of up to 55% in the Burley and Heyburn area over the next 20 years. This project includes the reconstruction of two existing Interstate I-84 interchanges, along with realignment of the existing interchange on and off ramps.

The project includes multiple bridges, as well as retaining walls and overhead signal structures.  Also included are a new design profile for the interstate highway and reconstruction of local roadways.  The total construction cost of the project is estimated to be about $70 million. 

Two interchange configurations were developed by the design team to meet the project goals, a tight diamond interchange and a diverging diamond interchange. Technical challenges include pre-loading of embankments and use of lightweight foamed concrete fill since this project is being constructed on an ancient lakebed deposit, projected to have formed during the Ice Age.  In contrast to the typical sand and gravel outwash deposits overlying volcanic basalt bedrock normally encountered in Southern-Central Idaho, the subsurface profile at this site consists of over 300 feet of interbedded clays, silts, and sands overlying basalt bedrock.  

For the site investigation, cone penetrometer (CPT) soundings were utilized to provide a continuous profile of the subsurface soil conditions and to record sleeve friction, cone resistance, and porewater pressures. The CPT results were used determine the in-situ soil properties for design of the pile foundations for the bridges. In addition, drill rig borings were performed to confirm the subsurface site conditions, and to obtain soil samples for laboratory testing. The CPT data combined with the drilling and laboratory testing provided a comprehensive understanding of the subsurface soil conditions. 

The proposed three span bridges at the Heyburn interchange will be 578 feet long and cross over an eastern Idaho rail line, a canal, and a state highway. The proposed two span bridges at the Burley interchange bridges will be about 200 feet long and cross over the I-84 highway.  Construction of the bridges will be in stages to keep traffic flowing at the interchange locations during construction. 

transportation Highways / Roads
Pavement Laboratory Geotechnical Engineering


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