This just in: An earthquake hit part of the Cornell campus on Feb. 26, resulting in severe building damage, broken concrete and a lot of data. "I would say this building is irreparable. It may be that the whole building will have to be demolished," said Richard N. White, the James A. Friend Family Distinguished Professor of Engineering and professor of civil and environmental engineering.

But don't worry -- it was a simulated earthquake of a 1/4-scale building, using a shake table in Cornell's "structure lab" in the basement of Thurston Hall. The earthquake, which would have registered about 8.2 on the Richter scale -- a severe earthquake -- was part of dissertation research by Ahmed Abdel-Mouti, a doctoral student sponsored by the Egyptian government in Cornell's School of Civil and Environmental Engineering. While his doctoral research is at Cornell, the Ph.D. will be awarded by Aim Shams University in Cairo. Abdel-Mouti and Timothy Bond, manager of the George Winter Laboratory of Structural Engineering, built a 1/4-scale concrete building typical of many buildings in this country and in Egypt -- with a reinforced concrete exterior frame, but with interior, infilled walls. These walls, basically concrete blocks put together with layers of mortar such as that used in common construction, generally are not considered part of the structural integrity of a building, but Abdel-Mouti's experiment, sponsored by the Egyptian government, is showing something different.

After a 32-second amplified version of an earthquake on the shake table, the masonry walls crumbled in parts but did not collapse. The walls made a difference, although several of the reinforced columns failed. It was the first such test on an infilled building.

"This is exactly what we had hoped for -- incipient building failure without collapse. With failure, the building does not function, but it is still standing," Abdel-Mouti said.

Infilled interior walls make a difference in the integrity of the structure, and construction standards should consider them in design calculations, the researchers said.

White, Abdel-Mouti's adviser, said that previous tests of concrete structures on the shake table, without infilled walls, collapsed at much less severe earthquake forces. Abdel-Mouti's research, he said, "will certainly help clarify the beneficial role of infills in buildings. True dynamic tests on realistic infilled building models have never been done before. Infills are often ignored in design calculations, but they certainly have a major role in the strength of the structure. This would have collapsed without them, at much less load."

It was no easy task. Bond outfitted the shake table to measure every useful parameter. About 120 sensors measured accelerations, displacements and loads. Five computers collected data simultaneously, from sensors making 300 measurements per second per channel for all 120 channels. That translates, Bond said, "to 9,600 data points per channel" in the experiment's

32-second duration.

"This will help us characterize the change that occurs when you put walls in," Bond said. "You can make better analytical tools as a result, to analyze the response of existing structures."

"This is a typical, common residential building. It is not designed to resist earthquake or wind damage," Abdel-Mouti said. "We need to know how the structure will behave and how these walls will perform in an earthquake. We built this to be exactly like a real building, just a smaller scale."

The shake table is basically a 5-by-7-foot aluminum plate driven by a hydraulic actuator powered by high-pressure oil and controlled by electronics. It sits atop a super-smooth granite slab with a layer of oil in between to reduce friction to almost zero. During the "earthquake," pieces of concrete clearly were jarred loose, leaving gaping holes in the sides of the building.

"There is severe deterioration with permanent deformations," Abdel-Mouti said. "The building is just not reparable."