The Missouri Department of Transportation (MoDOT) selected Hanson for preliminary design, final design, and preparation of contract plans services for the 3.67-mile rehabilitation of Interstate 255 (I-255). The project area extended from Interstate 55 (I-55) to the Jefferson Barracks Bridges, and it included the I-55/I-255 cloverleaf and Koch Road in addition to the ramps for Lemay Ferry, Lindbergh, Telegraph (Highway 231), and Koch roads.
The design plans included details regarding temporary and final pavement markings, raised pavement markers, Type C barriers, traffic control, erosion control, signals and culverts.
Hanson provided preliminary and final design surveys, including field surveys to locate existing signs, guardrail and fencing. The team performed a topographic survey at Koch Road where the roadway was reconstructed on a new profile to increase the clearance under the I-255 overpass. During the final design phase, Hanson’s team performed pick-up surveys and construction staking to gather data and provide control for the final design of the project.
The construction scope included coldmilling, pavement repair, eight-inch unbonded Portland Cement Concrete (PCC) overlay, bonded PCC overlay, full-depth PCC reconstruction, asphalt concrete cement (ACC) overlay, median barrier, and the total replacement of guardrail and signage.
The project’s scope also incorporated lighting design for the Jefferson Barracks Bridge. Electrical engineering responsibilities, which involved extensive coordination with the area’s electric utility company, included the development of preliminary and final demolition, new lighting, and wiring plans — including poles and lighting controls.
Traffic control was a significant challenge on this project as I-255 is a critical urban interstate corridor. Hanson produced a comprehensive two-stage traffic control plan to construct the PCC pavement and overlay while maintaining two lanes of traffic in each direction on I-255 at all times. Close coordination was required with MoDOT staff to estimate the durations of ramp closures during construction and to identify methods of accelerating the work to minimize disruptions.
This project was a high priority for MoDOT, and Hanson personnel participated in several meetings with the department to discuss innovative construction and contracting methods to optimize the cost and duration of this project.