Pasadena, Calif. — Parsons received the 2017 Grand Award in the transportation category from the American Council of Engineering Companies of Missouri (ACEC/MO) for the Columbia I-70 Bridges design-build project. Parsons was the lead designer for this $18 million project for the Missouri Department of Transportation (MoDOT), which involved replacing six deficient bridges with five new weathering steel plate girder bridges while accommodating more than 80,000 vehicles per day on I-70.


“As the major interstate corridor across Missouri, it was critical to maintain traffic flow on I-70 during construction and complete the project quickly and cost effectively,” said Michael Johnson, Parsons Group President. “Parsons’ design accomplished all these things — and increased worker and public safety, too — by incorporating accelerated bridge technology on three of the five new bridges.”

Built in 1957, the existing three sets of concrete slab I 70 bridges were located within a 2-mile stretch of I-70 at Business Loop, Garth Avenue, and Range Line. To maintain traffic on I-70 during construction, the westbound single-span bridges of Garth Avenue and Range Line were designed and built using slide-in bridge construction (SIBC) in which the new bridges were built adjacent to the old bridges and then slid into their permanent location after the old bridges were demolished. The eastbound spans of these two bridges were constructed using the traditional bridge-building method whereby the old bridge is demolished and a new bridge is built in its place. The twin spans of the Business Loop Bridge were replaced with one single-span bridge, which also used the SIBC accelerated bridge construction technique to slide the new structure into place. It was positioned in a slightly different location than the old bridge to better accommodate intersecting traffic.

In addition to delivering designs for accelerated bridge construction, Parsons also provided innovative new interchange designs at Business Loop and Range Line, which increased corridor mobility, enhanced pedestrian connectivity, and improved motorist safety. The Range Line/I-70 interchange was converted from a signalized diamond interchange to a dog-bone configuration, which consists of two tear shaped roundabouts that join together to form a single roundabout. The Business Loop/I-70 interchange was improved with dual-lane roundabouts on the north and south sides of I 70.

ACEC/MO’s annual Engineering Excellence Awards recognize quality engineering design based on uniqueness; innovation; social, economic, and sustainable development; project complexity; value to the engineering profession; and fulfillment of client/owner needs. Based on this regional ACEC award recognition, the I-70 Bridges project is now eligible for ACEC’s national 2017 Engineering Excellence Awards, which honors the world’s best engineering achievements.