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Dr. David V. Rosowsky

Texas A&M Engineering professor shakes things up with earthquake tests

A two-story, 1,800 square-foot, fully furnished townhouse was built and placed inside the lab on two moveable, piston-powered shake tables, among the largest of their kind in the United States. Engineers and researchers jolted, shook and rattled the house in a series of five mock earthquakes that grew in size and magnitude.

Most Texans have little reason to think about earthquakes or seismic damage much in their everyday lives. But for Dr. David Rosowsky of Texas A&M University, extreme events like earthquakes, hurricanes and the performance of structures under such conditions are more than just an interest - they are his passion.

Learn more about Dr. David Rosowsky by visiting his website at http://ceprofs.civil.tamu.edu/drosowsky/

Rosowsky, department head and A.P. and Florence Wiley Chair Professor in the Zachry Department of Civil Engineering at Texas A&M and a researcher in the Texas Engineering Experiment Station, is part of a team working on a four-year, $1.24 million project funded by the National Science Foundation through the Network for Earthquake Engineering Simulation (NEES). The project studies the performance of engineered wood structures subjected to seismic loading.

The project's first phase included a large-scale test conducted in the summer of 2006 at the University of Buffalo's Structural Engineering and Earthquake Simulation Lab, and was led by a team of faculty and students from Colorado State University, University of Buffalo, Texas A&M, Cornell University and Rensselaer Polytechnic Institute. A two-story, 1,800 square-foot, fully furnished townhouse was built and placed inside the lab on two moveable, piston-powered shake tables, among the largest of their kind in the United States. Engineers and researchers jolted, shook and rattled the house in a series of five mock earthquakes that grew in size and magnitude.

According to Rosowsky, wood is one of the most common construction materials for residential and other low-rise structures in the country. This fact, coupled with the growing interest in building taller wood frame structures in some of the most seismically active parts of the country, produces a need to develop an engineering design philosophy for wood structures built in earthquake-prone regions to ensure life safety and minimize structural damage and costs to acceptable levels.

"We hope to use the data collected from this project to better understand how wood structures behave under earthquake loads," Rosowsky said. "If we can predict where the weaknesses lie within these structures, we can take steps to strengthen those problem areas, and build structures better able to withstand the damaging earthquake forces, minimizing structural displacement and the resulting damage."

The fourth shake test of the project rattled the townhouse with the force of a magnitude 6.4 earthquake, much like the one that pummeled Northridge, Calif., in 1994. That disaster resulted in 60 deaths and is believed to be the costliest earthquake in U.S. history, with damages reaching $40 billion.

The test house was put to the ultimate trial with the fifth and final experiment on Nov. 14 when it was subjected to what is known as the maximum credible earthquake. This earthquake is the strongest possible quake at a given area based on the local seismology and geology. This final test of phase one resembled the infamous 1906 San Francisco earthquake that produced tremors measuring from 7.7 to 8.3 on the Richter scale and resulted in the loss of around 3,000 lives.

Phase two takes the project across the globe to Miki City, Japan. There in early 2009, Rosowsky and the team of researchers will test a six-story building on E-Defense, the world's largest shake table.

"While wood structures are not as ubiquitous in Japan as they are in the United States, North American 'stick-frame' style construction is gaining popularity and both American and Canadian companies are moving to capitalize on great new opportunities," Rosowsky said.

With Japan located in a highly seismic region, Rosowsky believes that both the United States and Japan have strong incentives to develop new, engineered design procedures for wood frame structures subject to earthquake loading.

"These tests, conducted in the United States and in Japan, are the largest shake- table tests of wood frame structures ever performed," Rosowsky said. "We can learn an enormous amount from this project and through the development of new design procedures, have a significant impact on the safety and damage resistance of a very large class of buildings."

Dr. David Trejo

CE Faculty, Student Investigate Kennedy Space Center's Launch Complex

Dr. David Trejo (left) and undergraduate student Justin Rutkowski have received NASA research fellowships to research Kennedy Space Center's space shuttle launch complex.

Trejo (right) and Rutkowski inspect the refractory materials in the flame deflector units at Launch Complex 39B.

Although most people only see the space shuttle launch and workings thereafter, significant effort is spent on maintaining and rehabilitating the infrastructure needed to launch the space shuttle. The infrastructure performance is critical for successful launches!

Learn more about Dr. David Trejo by visiting his website at http://ceprofs.civil.tamu.edu/dtrejo/

Texas A&M's Dr. David Trejo and Justin Rutkowski, associate professor and undergraduate student in the Zachry Department of Civil Engineering, have received 2005 NASA research fellowships to investigate and perform research on the performance, durability, and service-life prediction of the space shuttle launch complex at the Kennedy Space Center (KSC) in Cape Canaveral, Fla.

The space shuttle launch complex is a steel framed and reinforced concrete composite structure. The flame deflector at the launch complex, which diverts the flames and exhaust away from the space shuttle during launches, is a steel framed structure. During launches temperatures often exceed 3000 oF. Because steel does not perform well under high-temperature conditions, the steel frame is covered and protected with refractory materials. Although these refractory materials protect the base structure, the load and thermal stresses during launches have caused failure of the refractory materials. When these materials fail during launch conditions, they become flying object debris (FODs) and are projected at high velocities. These FODs can cause damage to the launch complex and/or orbiter.

The infrastructure at the launch complex is aging and deterioration of the base structure and the refractory materials are generating safety concerns. Trejo and Rutkowski are performing research on the corrosion susceptibility of the steel in launch and post-launch environments and are developing plans to instrument the launch complex to define environmental conditions during shuttle launches.

Dr. Trejo is also developing a statistically-based experimental qualification program, with assistance from A&M graduate student Ceki Halmen, to evaluate refractory materials for possible use in the flame deflectors at KSC.

Rutkowski is evaluating the performance of different refractory materials and researching the migration of nanoparticles into cementitious materials to enhance the durability and service life and reduce the corrosion activity of the steel reinforcement of reinforced concrete structures contaminated with chloride ions.

It is anticipated that results from the corrosion research will provide a better understanding of basic corrosion mechanisms and will provide a basis for developing new materials and new repair procedures for use at the launch complex. The new qualification test program will provide a reliable test program for selecting high-performance refractory materials for use in the flame deflector units on the launch complex.

With the new Crew Exploratory Vehicle expected to make its maiden voyage in 2011 and expectations that this new space vehicle will use the existing launch complex, understanding the mechanisms of deterioration and selecting materials that provide longer-term performance will increase the safety and economy of the launch structures. In addition, because FODs can impact the launch facilities or space vehicle, better materials are needed to increase safety and economy.

Dr. Eyad Masad

CE Professor uses powerful X-ray technology to improve infrastructure materials

Dr. Eyad Masad uses the X-ray computed tomography machine to analyze infrastructure materials.

If you have ever swerved to miss another vehicle while driving, yet somehow remained on the road, you may owe your safe ride to Dr. Eyad Masad’s research in materials engineering.

Your vehicle regained traction instead of veering off the highway because of the friction between the highway surface and your vehicle’s tires. Pavement friction is essential to road safety and is only one aspect of Masad’s research exploring infrastructure materials such as asphalt, rock, and soils. By examining a material’s internal structure, or microstructure, investigating its properties, and then enhancing its design, Masad develops safer roads that save taxpayers money, prevent accidents, and even save lives.

Learn more about Dr. Eyad Masad by visiting his website at http://ceprofs.civil.tamu.edu/emasad

Masad, E.B. Snead I Associate Professor in the Zachry Department of Civil Engineering at Texas A&M University, helps make roads safer and more efficient through advanced technology unique to A&M. In November 2006, Masad began analyzing the microstructure of various infrastructure materials with an X-ray Computed Tomography Machine (X-ray CT) in the department’s Advanced Characterization of Infrastructure Materials Lab.

“This machine tells us why the material is performing better — what’s going on inside that makes it better — and then how I can change the internal structure to make it perform even better,” said Masad. “The bottom line of all our research is how to design materials that can help sustain our infrastructure.”

Fewer than five other universities in the nation have an X-ray CT and currently only Texas A&M uses the machine for civil engineering purposes. According to Masad, the machine functions by using the same science as a medical X-ray machine, but at a much higher intensity and power.

The experimental aspect of this research begins with precise measurements and images of the inside of the material, produced by the X-ray CT. Masad then analyzes these readings, develops mathematical models of the material’s properties, and seeks to enhance the longevity and safety performance of the material.

After first verifying that the material has no failures or cracks, Masad then tries to push the envelope and increase the endurance of the material by improving its load strength and durability. Masad said that ensuring uniformity within the microstructure and contacts between particles is one way he improves a material.

These improvements significantly benefit infrastructures, communities, and therefore individuals, according to Masad. Enhancing highways even helps automobile owners financially.

“When you drive on a damaged road, you are damaging your car.” In addition to positively affecting consumers’ pocketbooks, Masad’s research also reduces infrastructure costs caused by delay, consumption, and re-building.

“When I help make roads better, I feel I contribute to the well-being of society,” he said. “That gives me satisfaction. I know how to make things work better, and it has an impact on everybody’s life.”

Masad is able to make these contributions because of funding from the National Science Foundation, the Federal Highway Administration and the Texas Department of Transportation.

Masad admits that while there is significant satisfaction in his research, it can be frustrating because the applications of his discoveries usually take years to actualize. Before coming to academia, Masad was solely a researcher, but he now balances his research efforts by teaching both graduate and undergraduate students. When he is teaching, he feels he makes an immediate impact.

“Students might not know something before class and then they know it after I finish my lecture, so that makes me happy. I’m satisfied that I’m educating future engineers,” Masad said.

Masad enjoys seeing his students excel both academically and professionally. Often after just two years, he gets to see his former students succeeding in engineering companies.

Through his research, Masad discovers how to improve infrastructures’ interiors and through his teaching, he equips his students to make their own discoveries.