A research project Mid-States Concrete Industries has proudly participated in has recently received a grant from the ACI Foundation’s Concrete Research Council for its next phase.
The research, led by Gustavo Parra-Montesinos of the University of Wisconsin – Madison, is titled “Deformed Steel Fibers as Minimum Shear Reinforcement in Deep, Prestressed Concrete Hollow-Core Slabs.” The premise of the study is that precast, prestressed hollowcore slabs are widely used in residential and industrial construction due to their light weight, low cost and quick installation in the field. However, research has shown that the web-shear cracking strength of relatively deep hollowcore slabs could be substantially lower than that corresponding to the nominal web-cracking shear strength. In the past, the only feasible solution when increased shear strength is required, has been to fill the cores with concrete, which adds both weight and material/labor costs.
The research investigates a potentially more cost effective solution – using deformed steel fibers to increase shear strength. Researchers are trying to generate the necessary experimental data to evaluate the conditions under which steel fibers may be used as minimum shear reinforcement in deep precast, prestressed hollowcore concrete slabs.
Mid-States Concrete Industries own Vas Dudnik, Structural Designer, worked with Parra-Montesinos on the first phase of research, funded through a PCI Daniel P. Jenny Fellowship, from 2013 to 2015, while completing his graduate studies at University of Wisconsin – Madison.
During that time, Mid-States provided all the slabs and assistance requested for the research, even welcoming the researchers into the plant.
“Without Mid-States, there would be no research really,” Vas said.
For Vas, using a one-million pound machine and infrared high speed camera to test the slabs, and trying to figure out how to navigate a crane in the lab were definitely highlights, and so was working with Gustavo, whom Vas has deep respect for as both a professor and researcher.
“Working with (Gustavo) was a great opportunity,” Vas said. “It was a good learning experience (and) I worked with great people there.”
The second phase of Gustavo’s research will be funded by the ACI Foundation’s Concrete Research Council. It is one of only four projects selected to receive the grant. There were 31 applicants.
“Mid-States agreed, when I was proposing this to the foundation, to provide 16” deep hollowcore slabs,” Gustavo said.
He will test these slabs, and slabs from another producer, during this phase of research. Mid-States looks forward to working with Gustavo in the coming months.