Route 8/I-84 Interchange

Commonly referred to as “The Mixmaster,” the Route 8/I-84 interchange consists of stacked viaduct structures carrying Routes 8 and I-84 and a series of elevated ramp structures. This Value Engineering (VE) study evaluated the rehabilitation of eight bridges, a proposed temporary by-pass road used as a key element for the Maintenance and Protection of Traffic (MPT), and the use of a temporary U-turn as part of the planned detour proposal.

The goal of the project was to extend the useful life of the structure for approximately 25 years—to allow for an interim fix—while the interchange was redesigned and rebuilt. One major design consideration for the proposed rehabilitation was the maintenance and protection of traffic. Due to the traffic volume which passes through this busy interchange daily, impacts to traffic resulting from construction activities needed to be considered.

The proposed design includes a temporary two-lane bypass roadway to maintain traffic along Route 8 NB (through traffic and traffic feeding I-84 ramps) during a complete deck replacement on Bridge No. 3190A. Due to the magnitude of work associated with this bypass roadway, the VE team chose this feature for further evaluation in the VE study.

The VE team studied the As Given elements and developed proposals for four alternatives.

The VE study was performed under Benesch’s 5-year task-based services contract to provide constructability reviews, value engineering analysis and other related tasks associated with improving the quality of contract documents as part of the Department’s Quality Assurance initiative.