Smart Concrete: Innovation for Our Future
(This article is written by Rick Petricca, VP of Petricca Industries, Inc. in Pittsfield, MA. Unistress Corporation is the primary company of Petricca Industries. John Barber, immediate past president of the New York Capital Region Chapter (Albany, NY) is the Controller for Petricca Industries, Inc.)
Innovate scientific techniques over the years allow concrete to “tell you how it is feeling.” These new Smart Concrete innovations are the way of the future for concrete structure design and will have a significant impact on the safety and longevity of all concrete structures.
The world we live in is constantly changing, with the frequency and severity of disasters increasing. Prior to the 9/11 attacks, the engineering world focused on building earthquake-resistant structures. Since then, the focus has broadened to include impact- and blast-resistant structures. Precast concrete offers a variety of versatile approaches to achieving whatever goals a designer sets for his structures. Now, scientists are even looking at ways to let “smart concrete” tell us how it’s feeling.
Obviously, life safety must be the primary goal for safety systems. But the second major objective is designing structures that can withstand disasters, natural or otherwise, without collapsing and then be re-occupied without overwhelming repair costs. The new design for seismic- or impact-resistant precast concrete structures feature bracing systems and connections that are ductile and that will dissipate energy, flex and then return back to nearly their original state.
A variety of research and testing programs continue to determine the best designs and systems to be used for buildings or bridges. These programs cover various shapes and sizes, in various seismic zones, or with varying threats of impact.
In 1999, a large research program supported by PCI (Precast/Prestressed Concrete Institute) developed a 60-percent scale, five-story precast concrete building model. This structure incorporated various seismic frame systems tested under simulated seismic loading. By incorporating various design systems within the same test, engineers were able to compare the results of the different systems under different seismic loads. This research program was named PRESSS (Precast Seismic Structural Systems).
In the aftermath of earthquakes, 9/11, tsunamis, and other major disasters, studies have been conducted on the failures or successes of concrete structures. The aftermath studies try to piece together the cause-and-effect relationships of what happened. This is not as effective as having monitored data produced from a scale model under a controlled environment as in PRESSS.
Building owners have a real need to monitor the ongoing condition of concrete structures and predict their performance or potential failure under stress. Historically, the only way to monitor any structures condition was to physically go out and inspect them. Physically inspecting structures is inefficient, costly, impractical, and not always accurate because often much of the structure is not visually accessible.
Over the years, innovative techniques have been developed to monitor concrete through the use of embedded probes, strain gauges, and thermocouples wired to data acquisition systems. This type of data-collection testing has proven useful in furthering the design of precast and pre-stressed concrete structures. Physical inspection, testing, and measurements, combined with remote-data acquisition, are the way in which design assumptions are validated and designs are improved upon.
Recently, the term “Smart Concrete” is being used to describe concrete that can “tell you how it’s feeling” so to speak. Unistress Corporation and I have been working to help promote this new “Smart Concrete” technology within universities. We know that this will have a huge impact on the welfare and economics of our society.
Unistress Corporation is trying to gain support of research projects at WPI (Worcester Polytechnic Institute) related to developing smart technology for high impact and fire resistance of pre-stress concrete. I also had the pleasure of being part of a video done by NBC Learn, in conjunction with Deborah Chung, a NSF-funded scientist at the State University of New York at Buffalo. NBC Learn produces a variety of educational videos for teens and young adults. The title of this video is “Science of Innovation: Smart Concrete.”
Chung discovered that by adding carbon fibers to concrete, the concrete became a sensor allowing the entire structure to conduct electricity. The concrete can now detect the stresses inside of itself and minute changes in stress can be monitored. This innovative idea will allow detection of hidden stresses in concrete structures before a real problem occurs.
Please contact Rick Petricca (413-629-2005; Rick.Petricca@unistresscorp.com) for more information.
(The video referenced by Rick Petricca shown on NBCLearn.com can be viewed by clicking here.)