Concrete solutions: Stronger materials for more sustainable structures
September 19, 2007
Concrete is the most widely used construction material in the world. In the United States alone, demand for concrete has almost doubled since the early 1990s, driving up its cost in the global market.
When concrete structures age, they are often torn down and replaced. But where this option is too expensive — as it is in many underdeveloped countries — these deteriorating structures become life-threatening hazards, especially in regions prone to earthquakes and other natural disasters.
The danger posed by older buildings, combined with the growing call for more sustainable construction practices in the industrialized world, has engineers and industry experts experimenting with new methods and materials in the quest to build more durable, energy-efficient buildings.
In a cover story in the April 2007 edition of STRUCTURE® magazine, Arizona State University professor of civil and environmental engineering Barzin Mobasher and collaborator Brian Rajii with the Seattle-based engineering consulting company KPFF detail their efforts to improve the structural viability of concrete buildings with advances in carbon fiber reinforced polymer (CFRP) technology.
The research, sponsored by KPFF and Pipe Reconstruction Inc., evaluated the performance and behavior of reinforced concrete exterior beam column joints that were reinforced and rehabilitated using CFRPs.
“We are taking a critical look at the ability of carbon fibers to support aging concrete structures. When bonded to the surface of beam column connections, they support the structure in several ways as a repair and strengthening system,” says Mobasher. “We want to document these effects and develop design tools for general rehabilitation of structures.”
The research was conducted in the Department of Civil and Environmental Engineering’s Structural Mechanics Laboratory (pictured on the magazine cover). The facility enables engineers to perform mechanical testing of a variety of materials and building systems. They can test materials for shock vibration, fatigue, uniaxial and biaxial loading conditions. They also can test materials to see how they perform at high speeds in crash and impact events.
With advances in CFRP techniques, Mobasher and Rajii are addressing a critical global need for more sustainable building techniques. The development of techniques like CFRP and concrete alternatives that extend the life cycle of buildings could improve the quality of life for millions of people around the world.
STRUCTURE® magazine is a joint publication of the National Council of Structural Engineers Associations (NCSEA), Council of American Structural Engineers (CASE), and the Structural Engineering Institute (SEI). The magazine’s circulation includes more than 30,000 readers, an estimated 28,000 of whom are practicing structural engineers — every member of the leading structural engineering associations.