Structures and Materials Lab Lets Researchers Explore How Materials React
Wouldn't it be great if you could use self-consolidating concrete that wouldn't need to be vibrated but rather poured like cake batter? What's the optimal dosage to create such a product? Would that concrete still bond properly to materials like rebar, especially if that rebar were made from a rust-proof composite (or plastic) material? And would those composite bars within concrete still provide structural resistance to withstand an earthquake?
Those are the kinds of questions that faculty and students explore in the 4-year-old Structures and Materials Laboratories at Morgan State University, which contain some unusual equipment. Hunkered deep within reinforced walls, an earthquake simulator - which can go up to 8.0 on the Richter scale - offers a 3-meter-by 3-meter platform that can hold specimens of up to 10,000 kilograms.
"We can do qualification testing," says Dr. Monique Head, associate professor of structural engineering, explaining the table has six degrees of freedom and can go back and forth and sideways. "Yaw, roll and pitch are the technical terms."
Morgan also has a smaller shake table, and a machine that can do static and dynamic testing and torsion in a temperature-controlled chamber. It's used for, among other experiments, fatigue testing. To capture sensory information, the lab boasts a scanning vibrometer, which works like an incredibly high-speed camera to take pictures of specimens that are moving fast or dynamically.
A freeze-thaw chamber lets researchers examine the effects of weather, while other machines measure how much force it takes until a piece of rebar snaps or a concrete beam flexes, shears or even collapses. Two large overhead cranes ferry samples of up to 5 tons. A drop tower finds out how much energy it takes to punch through various materials, which has applications that, although somewhat scary to the layman, are useful in the aeronautical field and for material characterization.
"Our whole goal is to use advanced materials for sustainability," says Dr. Head. "Here, students can see how theory meets practical application. They can put weight on something and see how it holds up."
The lab is used not just by engineering majors but by architecture students as well, who observe tests on what might well be the building materials of the future. Graduate and undergraduate students participate in the ongoing research conducted in the lab.
Examples of recently completed research reports include Structural Health Monitoring to Determine Long-term Behavior of AFRP Composite Bars in Prestressed Concrete Panels for Field Deployment, Stainless Steel Prestressing Strands and Bars for Use in Prestressed Concrete Girders and Slabs, and Durability Assessment of Prefabricated Bridge Elements and Systems. The reports are available at http://www.morgan.edu/school_of_engineering/research_centers/national_transportation_center/research/completed_projects.html.