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I-57/I-70 Rehabilitation

September 24, 2014

Highway and interchange design on I-57/I-70.

Increased congestion at the crossroads of two major freeways, I-57 and I-70, prompted the Illinois Department of Transportation (IDOT) to upgrade the section where the two highways merged through the City of Effingham. Lochmueller Group (Lochgroup) was hired to provide preliminary and final design of the roadway including five interchanges.

The additional lanes and interchange improvements would improve safety, reduce congestion, and allow for increased truck access for the movement of goods as the area continues to develop. As a result of the firm’s efforts on this $163 million project, Lochgroup received IDOT’s 2014 Award for Exceptional Consulting Engineering Service.

i57-70-2In all, Lochgroup designed the rehabilitation of 7.7 miles of roadway. This section of freeway is dual-marked and consists of 6 lanes and a 16-foot median. Lochgroup’s responsibilities also involved structural design for 11 bridges. Since the corridor serves as an essential national emergency route, the project also included the seismic rehabilitation of five bridges. Lochgroup developed in-house seismic retrofit details that restrain the bridge spans on their supports. The restraining devices were easy to construct, and they feature innovative indicator devices that will allow an emergency bridge inspector to evaluate if the restrainers are capable of resisting a second earthquake event or need to be replaced.

The bridge work also included design of three new bridges. One of the new bridges replaced the dual structures over US 45 and the Canadian National Railroad. Originally, the structures were only to be widened and rehabilitated. Due to the poor condition of one of the support piers, however, the project was re-scoped as a total replacement. This extra cost meant Lochgroup redoubled efforts to trim costs elsewhere to keep the overall project on budget. Lochgroup engineered a hybrid girder design as opposed to a standard grade 50 ksi steel plate girder. This reduced the amount of steel required for the plate girders by approximately 277,000 pounds saving at least $200,000.

i57-70A second new structure consisted of a 2-span bridge carrying a shared-use path over I-57/I-70 to support the local trail network. The bridge, which features a unique decorative railing, consists of a reinforced concrete deck supported by 40-inch steel composite web plate girders on a reinforced concrete pier and abutments. The abutments are wrapped around by Mechanically Stabilized Earth retaining walls.

The final new structure over Fayette Avenue is a 2-span bridge carrying a sidewalk, 4 lanes of traffic, and a turn lane. The schedule for design of the Fayette Avenue interchange was reduced by 14 months at IDOT’s request.

Final plans were broken into four phases to be constructed as funding became available and to allow local contractors to be able to bid on the projects. Construction was also coordinated with an adjacent project, I-70 over the Little Wabash River. The high potential for scour resulted in a complex structure design. By coordinating the two projects, Lochgroup saved IDOT approximately $1.2 million through changes to the construction phasing and compressing the design schedule from 18 to 12 months.

Another key to the success of the overall project was an intensive traffic management plan for multiple, overlapping construction contracts. This includes automated real-time work zone system with traffic sensors, video cameras, and message signs including alternate route detour and advance lane closure warning signs. Working with IDOT ITS managers and manufacturers, the plan resulted in few work queuing issues and accidents.

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