Millions of dollars are spent fortifying dams to withstand earthquakes — but it may not be necessary. New research being conducted at Rensselaer Polytechnic Institute is examining whether or not that spending actually contributes to public safety.
“The Army Corps of Engineers has spent hundreds of millions of dollars retrofitting some dams which may not need to be retrofitted,” said Tarek Abdoun, a chaired professor of civil and environmental engineering at Rensselaer who is leading this research with support from the National Science Foundation.
Abdoun and his team will build soil models to scale and place them inside a centrifuge on the Rensselaer campus. They will then simulate an earthquake and the pressure the soil would experience by spinning and shaking the model.
The Rensselaer team, which includes Ricardo Dobry, an Institute Professor of civil and environmental engineering, is specifically looking at soil liquefaction. This phenomenon, which is not well understood, occurs when earthquake shaking reduces the strength and stiffness of soil to the point that it behaves like a liquid.
Abdoun said that previous work by his group has shown that current engineering approaches underestimate the resistance of soil, which could be leading to unnecessary and costly new builds and retrofitting.
“The method being used doesn’t represent the field condition properly,” Abdoun said. “We are showing from our lab tests and the centrifuge — which is unique and can simulate more than in the field — that it behaves much stronger.”
Rensselaer is uniquely positioned to tackle this challenge because of its large centrifuge, which can simulate many different conditions, and the extensive expertise in the field of civil engineering at the university.
Abdoun hopes that by addressing this scientific gap in knowledge, Rensselaer engineers can make a recommendation for a more efficient and accurate approach to spending money on dam fortification.
This research is being done in collaboration with Geocomp Corporation, a leading geotechnical company that conducts soil lab testing and manufacturers lab and field testing equipment.