Quake Research to Provide Rare Glimpse of How Structures Collapse

Jun 04, 2008

Structural engineers at the University at Buffalo are conducting some of the most comprehensive experiments ever attempted to develop methods of evaluating and designing steel buildings so that they will be less vulnerable to collapse during strong earthquakes.

The experiments are part of a project aimed at both designing new structures that can withstand large deformations without collapsing and at evaluating existing buildings to determine where retrofits may be necessary.

The gap in information about how structures collapse became painfully clear last month after the 7.9 earthquake in Sichuan, China, when the tragic collapse of numerous schools throughout the province caused the deaths of thousands of schoolchildren, the UB researchers noted.

"The whole idea of this project is to find out how much damage a particular building can take before it collapses," said Gilberto Mosqueda, Ph.D., assistant professor in the UB Department of Civil, Structural and Environmental Engineering and principal investigator on the research.

He explained that the philosophy behind building codes is that while buildings may sustain damage in a strong earthquake, they should do so in such a way that the damage can be absorbed by the structure without collapsing so that people can safely evacuate.

"But many different factors besides design come into play, such as the quality of construction, the known seismicity of an area and the magnitude of an event," he continued.

"The problem from the structural side is that there is very little experimental data available to verify our models or assumptions on the nature of how structures collapse because these experiments are very difficult to do in a laboratory," he said.

Mosqueda said that the shake table facility in Miki City, Japan -- the world's largest -- is the only one in the world capable of subjecting full-scale structures to simulated ground motions that can trigger a collapse. Those experiments tend to be expensive in terms of cost, time and labor.

For that reason, Mosqueda has geared his research toward developing more realistic, reliable and economical ways of testing large-scale structures. To do this, his project will combine laboratory experiments of partial structures that can capture the initiation of a collapse either in slow-motion or in real-time with numerical simulations of the remaining full-scale building. This hybrid numerical and experimental model will then be subjected to earthquake loading.

In order to simulate the earthquake loads, the experimental portion of the research will employ high-performance hydraulic actuators that will push and pull elements of the partial structure plus or minus 20 inches at forces of up to 220,000 pounds. Experiments will be performed in UB's Structural Engineering and Earthquake Simulation Laboratory (SEESL) in the School of Engineering and Applied Sciences.

"Through these experiments, we will be able to capture the interaction between a building's elements, such as columns, beams and floor slabs during strong ground motions," Mosqueda said.

Some of those experiments will be conducted over the Internet, with pieces of the same structure simultaneously being tested at UB and Kyoto University, Japan, while numerical simulations will produce data on how the entire structure would perform under the same conditions. These "distributed hybrid tests," as they are called, are made possible by international collaborators and the National Science Foundation's George E. Brown Jr. Network for Earthquake Engineering Simulation (NEES) Facility, a nationwide earthquake-engineering "collaboratory" of which UB is a key node.

Mosqueda's project is the result of a prestigious $400,000 Faculty Early Career Development Award he received from the NSF to develop a "Hybrid Simulation Platform for Seismic Performance Evaluation of Structures Through Collapse." According to the NSF, the CAREER program recognizes and supports the early career-development activities of teacher-scholars "who are most likely to become the academic leaders of the 21st century."

Source: University at Buffalo

Explore further: Comfortable climate indoors with porous glass

add to favorites email to friend print save as pdf

Related Stories

Image: Chandra's view of the Tycho Supernova remnant

1 hour ago

More than four centuries after Danish astronomer Tycho Brahe first observed the supernova that bears his name, the supernova remnant it created is now a bright source of X-rays. The supersonic expansion of ...

Recommended for you

Comfortable climate indoors with porous glass

11 hours ago

Proper humidity and temperature play a key role in indoor climate. In the future, establishing a comfortable indoor environment may rely on porous glass incorporated into plaster, as this regulates moisture ...

Crash-testing rivets

12 hours ago

Rivets have to reliably hold the chassis of an automobile together – even if there is a crash. Previously, it was difficult to predict with great precision how much load they could tolerate. A more advanced ...

Customized surface inspection

12 hours ago

The quality control of component surfaces is a complex undertaking. Researchers have engineered a high-precision modular inspection system that can be adapted on a customer-specific basis and integrated into ...

Sensors that improve rail transport safety

12 hours ago

A new kind of human-machine communication is to make it possible to detect damage to rail vehicles before it's too late and service trains only when they need it – all thanks to a cloud-supported, wireless ...

Tiny UAVs and hummingbirds are put to test

Jul 30, 2014

Hummingbirds in nature exhibit expert engineering skills, the only birds capable of sustained hovering. A team from the US, British Columbia, and the Netherlands have completed tests to learn more about the ...

User comments : 0