Michael Baker International Creates Safer Roadway with Widening of Highway 70 in Central Arkansas
PITTSBURGH, PA Michael Baker International is playing a critical role in the transformation of the heavily traveled Highway 70 between Interstate 30 and the City of Hot Springs, Arkansas. The firm recently completed a $4.5 million design project for the Arkansas State Highway and Transportation Department (AHTD) to widen the 19-mile stretch of highway from two lanes to four, in an effort to increase capacity and promote passenger safety.
"The Highway 70 corridor has experienced a number of fatal accidents, so Michael Baker's design efforts looked at ways to improve roadway conditions, such as straightening curves, flattening hills and changing geometrics of the highway," said Michael Stengel, Vice President and Office Executive for Michael Baker's Little Rock, Arkansas, office. "Utilizing 3D-modeling software, our team developed innovative and environmentally sound solutions for our partners at AHTD to improve the existing roadway and bridges."
As part of the contract, Michael Baker conducted an environmental study, provided roadway widening design and replaced the existing Caney Creek bridge and two bridges over Ten Mile Creek. Since the highway runs through a mountainous area with sharp curves and elevation changes, the team was challenged to notch, widen and correct deficiencies in curve radii and super-elevation, while still utilizing as much of the existing pavement as possible. Michael Baker's design team, led by Scott Thornsberry, flattened subgrade slopes on the low side of super-elevated sections to minimize ditch depths and right-of-way takes. A sharp curve at an existing intersection with the I-30 Frontage Road was unnegotiable for large trucks, so the Michael Baker team designed a solution to add a long sweeping curve that would allow trucks to safely use the intersection for turns.
Additionally, the Ten Mile Creek Bridge has historically presented environmental and flooding challenges, which resulted in high maintenance costs. Michael Baker bridge engineers, working in tandem with in-house hydraulic engineers, properly sized the replacement structure to allow the creek to seek its natural path without causing damage to the bridge or violating hydraulic requirements. To facilitate continuous traffic flow during construction, Michael Baker phased the bridge construction portion of the project. This required careful design and plan detailing to allow the structures to be built incrementally.
"The Michael Baker team looked beyond the present needs of the project to incorporate grading for a future bike path and utilized a portion of an abandoned railroad embankment in the design," said Stengel. "These are just some of the ways We Make a Difference for the future generations of this community."
The design phase of the project is complete, and construction is underway at a bid cost within one-percent of Michael Baker's construction cost estimate. Michael Baker will provide ongoing construction support services through the anticipated completion of construction in August 2018.