Pile Dynamics Inc. (PDI) recently teamed up with NASA’s Glenn Research Center engineers in Cleveland to fix a moisture problem with their concrete temperature sensors. The thermal sensors, equipped with NASA’s water resistant technology, will be placed in 16 150 feet-deep drilled shafts that will give the Eastbound George V. Voinovich Bridge in downtown Cleveland a foundation.
“It was great having the expertise and technology available from NASA help us with product development,” says Dean Cotton, senior engineer at PDI. “Pile Dynamics has added a number of employees just to manufacture our new product and we are happy with the great acceptance it gained in the industry.”
PDI reached out to Glenn Research Center materials researchers to investigate low cost, watertight materials that would make the thermal sensors resistant to the wet concrete environment in which they function. Sandi Miller, a Glenn materials expert, performed experiments that revealed properties of adhesives used in the manufacturing process and why they worked. She also suggested alternatives that would improve bonding to provide a waterproof seal.
The thermal sensors are encapsulated at regular intervals along the length of PDI thermal wire cables, used to assess the integrity and shape of cast in place concrete foundation.
To obtain the temperature measurements necessary for the assessment, the cables are installed in cast-in-place foundations prior to concrete being poured. Once the concrete pour is complete, the sensors start measuring temperatures. A day or two after, there may already be sufficient data for an engineer to approve the shaft, allowing construction to continue. This time frame is much shorter than other concrete integrity tests.
The collaboration was a result of the Adopt-a-City program that matched small and mid-size manufacturers with experts from NASA’s Glenn Research Center to help solve challenges with a new or existing product. In 2012, PDI was selected into the program to receive up to 40 hours of pro bono assistance.
“NASA experts validated the Pile Dynamics encapsulation process to ensure moisture did not harm their sensors,” says Paul Bartolotta, an Adopt-a-City coordinator and aerospace engineer at Glenn. “The validation process included a detailed microstructural analysis of the encapsulated sensors utilizing NASA's powerful electron microscopes.”
For more information, go to www.pile.com/tip.