Route 7 and I-49 Interchange Improvements

With the Route 7 bridge over I-49 reaching the end of its useful life, MoDOT sought a solution to replace the aging bridge while addressing the existing diamond intersection’s unique traffic patterns. An initial analysis by MoDOT indicated that a traditional four-lane diamond interchange and a three-lane diverging diamond interchange (DDI) performed similarly under the projected traffic volumes. 

Building off of this study, TREKK conducted a comprehensive interchange alternatives analysis, which determined that an innovative split DDI would be the preferred solution. Although the primary project purpose was to replace the aging bridge over I-49, TREKK added significant additional value to the project for minimal additional cost. The TREKK team provided an innovative and collaborative approach to replace the bridge with solutions that improve the interchange operations and maximize the benefits for Missouri’s taxpayers, the city of Harrisonville and MoDOT.

The separated DDI proved to be more cost effective based on the simplified construction approach. Because maintaining traffic during construction was a primary driver for design, this configuration allowed for most of the construction to occur with minimal impact to traffic at the interchange. Traffic control on I-49 was limited to one occurrence for bridge demolition. The innovative design concept allowed for construction to be completed three months early with minimal change orders.

The split DDI interchange allowed traffic to be maintained on the existing bridge while two new, two-span (104’-104’) Prestressed Concrete bridges with spill slopes were constructed. TREKK’s structural team evaluated various structure types to optimize bridge depth and minimize profile adjustments while providing adequate vertical clearance over I-49 with consideration for future widening.