“The seismic design philosophy which is accepted all over the world is based on protecting the structures from experiencing sudden collapse during earthquakes by designing them to behave in a ductile manner,” Andrawes says. “But this ductility is often linked with significant and permanent damage to critical structural components which jeopardizes the safety of the structure and reduces its ability to withstand strong seismic aftershocks.”
Andrawes will study the use of an innovative type of transverse reinforcement made of Shape Memory Alloys (SMAs)—materials that “remember” their original shape and return to it after deformation—to apply active confinement at the most critical locations in the structure. He will utilize the shape-memory feature of these smart materials to mitigate the level of damage in the structure while still maintaining the desired level of ductility and energy dissipation.
Andrawes will perform tri-axial tests and 3-D modeling of concrete structural components fitted with the new SMA reinforcement. He will study the durability and long-term behavior of the new reinforcement by mimicking realistic climate conditions in the laboratory and conducting field tests. Once the new method of reinforcement is better understood at the material and component levels, Andrawes will collaborate with bridge engineers from the Illinois Department of Transportation (IDOT) to apply this new technology on real bridges in Illinois.
Andrawes will study the new technology under earthquake scenarios that depict a strong seismic main shock followed by smaller aftershocks—a critical, yet overlooked, perspective, he says.
“In many cases, aftershocks cause more damage to the structure than the first shock.” Andrawes says. “Unfortunately, considering the impact of aftershocks in the pre-main shock design is almost missing from our current design provisions.”
The NSF grant will also help Andrawes bring earthquake engineering and smart materials into the classroom for students at the high school and college levels, as well as for practicing engineers. He plans to collaborate with the Women in Engineering Program of the College of Engineering to organize a summer camp for high school girls to teach them about the structural engineering profession and its impact on society. He is planning a training workshop for bridge engineers to educate them about the new reinforcement technology. He will also use the results of the research to develop class modules for his classes CEE463 Reinforced Concrete II and CEE468 Prestressed Concrete.
CAREER awards are the NSF’s most prestigious form of support and recognition for junior faculty who “exemplify the role of teacher-scholars through outstanding research, excellent education and the integration of education and research within the context of the mission of their organizations.”