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Keeping It Dry Below The Waterline

Published: May 2, 2016

Civil Engineering and Construction Engineering Management’s Luis Arboleda-Monsalve recently received approval by the National Science Foundation (NSF) for a $98,206 grant to run through July 2017 to fund his research into the performance of a fundamental element of urban construction, the cofferdam, a watertight enclosure pumped dry to permit construction work below the waterline.

The goal of Arboleda-Monsalve’s research is to study the tendency of today’s high-rise building excavations to use cofferdams which can be responsible for ground movements. The grant, explained the member of the university since 2014, supports research into how these geostructures are designed and presents a chance to advance the understanding of how soil and structures interact deep underground.

“The fundamental knowledge developed in this research will inspire new methods of analysis and design of offshore structures, deep foundations, wharfs and retaining structures and will advance the understanding of the soil-structure interaction in other types of geotechnical projects,” he said.

He is especially interested in the slippage possible when urban cofferdams are being constructed with modular pieces called sheet piles that are interlocked with other sections to form a circular excavation support system.

“If there is slippage in those connections, large deformations are expected. Deformation causes settlement that might potentially affect the surrounding infrastructure, and that is one of the effects I want to study,” he said.

He also wants to look at the separation between the sheet piles and the internal bracings that are typically made of concrete or steel ring beams which also can trigger additional deformations to the ones inherent of the main excavation activities.

“I am interested in all the details that surround the construction of the modern urban cofferdams,” he said. “The ultimate goal of this research is to create more sustainable and resilient urban environments by preserving and protecting existing infrastructure, which is often compromised when excessive deformations occur.”

Arboleda-Monsalve earned his B.S. from the National University of Colombia in 2004, his M.S. from Purdue in 2006 and his doctorate from Northwestern in 2014.

He feels one reason for his research proposal’s acceptance is the potential for developing fundamental new knowledge in geotechnical engineering, noting there is very little literature in the U.S. about the design and performance of structures like these cofferdams which are used more and more nowadays in urban environments.”

Arboleda-Monsalve also credited the grant project’s partnership with GEI Consultants and Scientists which has been involved in more than 35,000 construction projects in all 50 states since its founding in 1970.

“They provided field instrumentation results that I need to evaluate to calibrate the numerical models that I am working on. This project stands out as a collaborative effort between university and industry with the potential for a tremendous impact on the procedures industry is using nowadays. We have the potential to develop design procedures that no one has proposed before.”

Cofferdams, like the one pictured above, are temporary enclosures built to create a dry work environment in order for other work to proceed.
Cofferdams, like the one pictured above, are temporary enclosures built to create a dry work environment in order for other work to proceed.

He also points to a role for students in the grant with a graduate student and two undergraduates currently working side by side in his research. When the grant is complete in 2017, he’s hoping for two things—to publish the data in two major journal articles and to make an educational impact at CSULB.

“With grants like these, there is the potential for curriculum changes on such topics as braced excavations in urban environments and tunnel construction,” he said.

Using his grant’s data, he also hopes to have a class someday that teaches undergraduates about cofferdams.

“Our students will acquire a broad perspective on the design and construction of cofferdams,” he said. “I’m looking forward to presenting our data at upcoming national and international conferences.”

Arboleda-Monsalve remembers a degree of uncertainty when he originally put together his NSF proposal.

“I feel this grant represents a balance between theory and practice, so much so, in fact, that I didn’t think the NSF would support it because it is extremely practical,” he said. “The NSF is very interested in developing only fundamental knowledge. If there is only a little incremental knowledge, the NSF usually says no. It was a challenge to get the balance between theory and practice so the NSF could fund it.”

Arboleda-Monsalve believes the grant benefits both CSULB and himself.

“Winning an NSF grant opens doors to more NSF grants,” he said. “This is one of the most prestigious funding agencies for a researcher. I feel lucky that this first proposal to the NSF was funded. It is definitely an important milestone for me and it is great for the department. I feel lucky to have it and I think we’re going to have more coming soon.”