Scour evaluation probe helps minimise infrastructure risks

Researchers from North Carolina State University have developed a probe that allows engineers to assess the scour potential of soils at various depths and on site for the first time.

The probe could be used to help evaluate the safety of civil infrastructure before and after storm events.

Scour, or erosion of soil around structures due to water flow, is responsible for a range of critical infrastructure failures – from unstable bridges to the levees that gave way in the wake of Hurricane Katrina.

’The in situ scour evaluation probe, or ISEP, is the first technology that allows technicians in the field to measure the scour potential of soils without the need for excavation,’ said Dr Mo Gabr, a professor of civil, construction and environmental engineering at the university.

Understanding scour potential is important because it can help authorities prepare for, or minimise the impact of, events such as the failure of the levees in the wake of Katrina. Scour has also been linked to approximately 60 per cent of the bridge failures in the US, according to the US Federal Highway Administration.

’The ISEP’s ability to measure scour potential at different depths helps us predict how the soil will behave in the future as various layers of soil are eroded or scoured,’ Gabr said.

The ISEP will also allow end users to perform scour assessment more frequently, since they will not have to take physical samples back to a lab for analysis. More testing data means researchers will have a larger data set to work with, which should help them to more accurately predict scouring rates and behaviour.

The new probe uses a water jet to burrow a hole into soil. Researchers can track the rate at which the water displaces the soil to determine the scour rate. Researchers can also manipulate the velocity and flow rate of the water to simulate various natural events – from normal stream flow to hurricane-induced surges.

The researchers plan to take the ISEP to North Carolina’s Outer Banks later this month to help with research efforts related to dune erosion.