The InterAx geogrid solution saved approximately $3M (~$15/SY) over conventional undercut and replace, allowing construction to continue without additional delay.
- Contractor: Lehman Construction
- Owner: Missouri Department of Transportation
Soon after the reconstruction of approximately 8 miles of existing roadway began, MoDOT recognized that the exposed subgrade was extremely unstable to run heavy trucks. The initial plans included 18 inches of rock fill. Since this is a heavily traveled highway, MoDOT was on a tight schedule and didn’t want to increase aggregate base thickness.
MoDOT and Tensar representatives met on-site the next day to perform DCP testing on the exposed subgrade, affirming a new design subgrade CBR of 0.9% The Pass-a-Proofroll module in Tensar+ design software allowed the team to quickly determine the type of geogrid that was required with the planned 18 inches of aggregate. Since the critical mainline lanes receive most of the traffic, more strict performance criteria were used than along the shoulders.