Locating voids within the sub-base of roadways, railroad tracks, building foundations, and any other structure that relies on the base and sub-base to carry its load is critical. Over time the yearly cycle of weather creates situations where rainwater infiltrates the ground and erodes the sub-base through de-particularization. This process eventually results in void formations and loss of density under roadways and structures.
Infraspect has developed a unique inspection procedure called VoidScan™ that not only located these voids but can perform condition assessment of the base quantifying void formations and loss of density. Infraspect has performed Sub-base Condition Assessments within interstate highways, under foundations supporting heavy equipment, bridge approach roadways, commercial shipyards, and seawalls just to mention a few.
VoidScan™ can be configured to support void detection on interstate highways or in small confined areas. Its variables frequency can penetrate from 12 inches to 40 feet. VoidScan™ creates 2D and 3D images that allows our engineers to accurately evaluate the condition of the base behind, under, and around structures.
VoidScan™ can locate water intrusion from the surface, follow the intrusion through the base and locate its exit. This is valuable for determining roadway base density, the probably of void formations, and the ability of the base to support the roadway under traffic loads.
Objective: Perform an approach roadway condition assessment on a 2,440-foot concrete marine bridge, built in 1998. VoidScan™ was configured to scan from the top of the roadway to the water line of the bay. The following images are extracts for the condition assessment report:
3D view of approach roadway, approach slab, and bridge deck.
The image below is a slice of the above 3D image showing severe water intrusion from crack in asphalt at end of approach.
The image below shows the roadway surface and the crack along the outer edge of the approach slab.
This crack allowed rain water to penetrate the roadway and severely weakened the base under the approach slab.