This is the fifth profile in a GW Today series featuring faculty from the Columbian College of Arts and Sciences and the School of Engineering and Applied Science who are conducting research with an impact in Science and Engineering Hall.
Sameh Badie’s voice echoes throughout the mammoth high bay in Science and Engineering Hall. A 28-foot high concrete wall, dotted with rows of holes and capable of withstanding 300,000 pounds of force, towers above him.
For now, the three-story high bay—the tallest room in the George Washington University’s new building—looks more like an empty gymnasium than an experimental laboratory. But by summer, the 1,500-square-foot space will transform into a structural testing site.
Using hydraulic jacks, Dr. Badie and his graduate students will apply and remove pressure from a beam/slab set-up for two million cycles, a process called “fatigue load” testing that can take up to five weeks to complete. This will simulate the weight of cars traveling on and off of a bridge and allow the researchers to measure the effect of the load on the system’s deterioration.
“There is a lot of manpower required for this kind of testing,” said Dr. Badie, an associate professor of civil engineering in the School of Engineering and Applied Science. “To put everything in place takes about 100 hours of labor.”
It also requires pricey, high-quality equipment and a massive amount of space, something that the new science and engineering building finally provides Dr. Badie, who for years outsourced his experiments to test facilities as far as 1,200 miles from Washington, D.C., in Lincoln, Neb.
“Every screw that goes into this test, I have to be aware of it,” Dr. Badie said. “So continuously for about two years, I was on the phone with researchers in these labs every single day.”
The tests, which Dr. Badie can now conduct just two floors below his office, will be the impetus for designing safer, more durable and ultimately more cost-effective bridges.
It is critical work, considering that over 200 million trips are taken daily across deficient bridges in the nation’s 102 largest metropolitan regions. Almost 69,000 U.S. highway bridges, or more than 11 percent of the total, need to be repaired or replaced, according to the Federal Highway Administration. The agency estimated last spring that it would cost $7.3 billion to address troubled bridges in Virginia and $467 million in the District.
What’s Dr. Badie’s long-term solution? Design bridges that are built to last.
“Get in, Get out, Stay out”
One of Dr. Badie main research focuses—developing precast concrete deck panel systems—is of particular interest to the Federal Highway Administration.
In 2001, the administration launched the Accelerated Bridge Construction (ABC) initiative. It calls for innovative planning, design and construction methods in order to reduce onsite construction time when building or replacing bridges.
In the past, highway bridges in the United States were built using cast-in-place construction, meaning that deck forming, placement, steel bar tying and curing of deck concrete all happens on-site. It’s a time-consuming process that can close roads for weeks at a time. Bridges built by this method also require continuous maintenance, such as patching, sealing and applying overlays.
“In the northern part of the country especially, we find that most bridge slabs need to be replaced every 15 years,” Dr. Badie said. “When it snows, you have to lay down chemicals and salts, and it eats away the concrete.”
This inefficient approach has led to the development of new systems that employ precast concrete elements for highway bridges. In contrast to cast-in-place construction, precast concrete components are fabricated off-site and then connected on site, so bridges are constructed more rapidly. Instead of closing roads for up to five months to replace an old bridge deck, precast elements allow construction workers to build bridges in less than four weeks.
And though the precast concrete decks have a higher initial cost than cast-in-place elements, they also have a longer lifecycle.
“Because the parts are produced in a very controlled environment, bridges built with precast concrete are very durable and have high performance,” Dr. Badie said. “They can last up to 40 years, which is double the lifetime of regular cast-in-place concrete.”
The system epitomizes the ABC initiative’s primary motto: “Get in, get out, stay out.”
Though the use of precast elements has been steadily increasing in the past five years, the Federal Highway Administration is still looking for ways to perfect the system.
“It’s a lot like Legos—you have all these little pieces, and if you don’t connect them in just the right way, then you’re going to have a flimsy structure,” Dr. Badie said. “How you put all the pieces together is the $1 million question.”
For the past 14 years, Dr. Badie has been instrumental in the development of new connection details that increase construction speed while maintaining long-term durability. He served as the principal investigator on two research projects, sponsored by the National Academy of Sciences, in which he developed the second generation of precast concrete deck panel systems. One of these systems has been used on highway bridges in states across the country.
In his current project, Dr. Badie is developing a third generation system and developing guidelines for engineers to design these systems.
It is a large undertaking, in both size and scope, but Dr. Badie said it is well worth the effort to see his systems in action. In fact, this visibility is precisely what drew the structural engineer to bridges in the first place.
“With buildings, in most cases, all of the structural elements are hidden behind walls. You can’t see anything,” Dr. Badie said. “But with a bridge, everything is exposed. We structural engineers like seeing that.”
The Sky’s the Limit
In addition to the sheer size of the high bay, the lab’s “strong wall” and perpendicular “strong floor” will make Dr. Badie’s precast concrete testing possible.
Both the concrete wall and floor are reinforced with post-tensioned tendons. They have a high capacity for resisting forces that may pull or bend it apart, allowing Dr. Badie and other researchers who will utilize the high bay to test heavy, large-scale elements that may be up to 40-feet long and 20-feet high.
Having the high bay on campus means that Dr. Badie’s students will be able to see experiment setups and testing firsthand, instead of watching these tests on videos as they have in the past.
“They can now compare between analytical and experimental work,” Dr. Badie said.
The spacious lab also gives students hands-on opportunities outside of the classroom. For instance, after a decade-long hiatus from the competition, the GW chapter of the American Society of Civil Engineers will once again participate in the Concrete Canoe National Competition. The contest challenges civil engineering students across the country to build a 20-foot-long craft that will then be put to a test in a paddling race.
“There just wasn’t the space to build it in Tompkins,” said Elizabeth Manning, a junior studying civil engineering. “And now that we’re in the high bay, in such a central location, people are constantly walking by and coming in to see what we’re doing.”
As Dr. Badie waits for testing to begin this summer, he is confident that SEH will give him even more ways to integrate his research and teaching.
“It’s an exciting time,” he said.