Building safer roads and bridges
Developing new construction materials-composites, lightweight concretes, alloys-has enabled engineers to incorporate them in the design of striking bridges and structures, like Santiago Calatrava's arching suspension bridge under construction over the Trinity River in Dallas.
But dramatic though they may be, are they safe? Answering that question is the realm of civil engineering Professor Ali Abolmaali.
He leads the Structural Simulation Laboratory, where he and 10 post-doctoral fellows, graduate, and undergraduate students study stresses on a variety of structures and then create ways to divert them. Projects range from structural panels and aeronautical frames to underground structures, steel and composite poles, and even the human eye.
"We've been conducting several biomechanic simulations, including modeling the human eye lens," Dr. Abolmaali says. "As a result, several articles have been published in various medical journals. We like challenges."
Some of the challenges he and his team have taken on are funded projects for the Texas Department of Transportation (TxDOT), which wanted to standardize requirements for steel poles holding traffic monitoring cameras. Hanson Building Products sought help creating hurricane-resistant concrete wall panels. The American Concrete Pipe Association (ACPA) wanted structural data on culvert pipe designs, some as tall as eight feet.
TxDOT got its pole standards. Hanson's panels have been used in several structures in post-Katrina New Orleans, and the ACPA used the data to establish national specifications for concrete bridges.
For another TxDOT project, Abolmaali and a team of civil engineering and computer science and engineering faculty developed mounts that virtually eliminate vibrations of poles for freeway traffic cameras, providing clear pictures of roadway situations.
"That one is on its way for statewide implementation," he says.
Abolmaali creates the simulations using the finite element method, which combines geometry, the physical properties of materials, and loads applied to the materials. Problems are divided into a number of elements, the number of which is increased until reaching convergence-the closest to reality.
Many of the lab's structural projects have grabbed national headlines. In September 2006 the National Transportation Safety Board (NTSB) asked Abolmaali to assist in the investigation of structural failures in the I-90 connector tunnel in Boston. Earlier that year a ceiling panel collapsed, killing a woman and leading to closing one section of the tunnel. In 2009 the NTSB called again, requesting his services as an expert analyst to study the failure of the I-35 bridge in Minneapolis.
"Simulations have enabled us to thoroughly examine structural features to determine their design strengths and weaknesses," Abolmaali says. "An amazing amount of computational work can be accomplished with the high-powered processors we acquired through a research equipment grant from the National Science Foundation. They've been the backbone of what we've been able to accomplish, along with the contributions of other faculty members and students."