An innovative design for repairing steel infrastructure in canals and waterways is being developed by civil engineers at Colorado State University in the United States.
The team, led by assistant professor of civil and environmental engineering Hussam Mahmoud, is testing the structural integrity of a steel plate submerged in a churning water bath.
The plate represents a hydraulic structure called a mitre gate, which opens and closes in a river lock many times a day. A long, irregular crack is visible on the experimental plate’s surface.
Researchers are examining how the crack behaves in various conditions and at what point it leads to structural failure. Through the study, retrofits are also being tested. These are carbon fibre reinforced polymer sheets that are stuck to existing cracks with adhesive.
“The presence of a crack is not a big deal, until that crack propagates, and then it becomes a big deal – to the point where the structure could collapse,” said Mahmoud.
The tests involve a 3m vertical actuator to bear approximately 55,000kg of force on a cracked plate, while water flows around it in conditions similar to rivers and waterways. The plate is subjected to around 500,000 force cycles before the crack leads to structural failure.