BUFFALO, N.Y. The design of next-generation nuclear power plants
and other critical energy facilities will undoubtedly be influenced
by the Japanese tsunami and its devastating effects on Japan's
nuclear reactors, says Michael C. Constantinou, PhD, professor of
civil, structural and environmental engineering at the University
at Buffalo.
"If a nuclear reactor is built at a site where a 30-foot tsunami
wave is possible, if it comes, it is going to have a significant
effect, there is no way to control for that," says Constantinou, a
structural engineer, and researcher with UB's MCEER
(Multidisciplinary Center for Earthquake Engineering Research.) He
works on seismic protective systems that deflect and dissipate
seismic energy and protect structures during earthquakes.
"The only way to prevent the situation is to build the plant
further inland, to seismically isolate it and, perhaps, to elevate
it," he says.
According to Constantinou, it is possible to seismically isolate
an entire facility on a concrete platform.
"This is possible technologically, but much more complex," he
says.
Constantinou is familiar with this technique, having consulted
with UB colleague Andrew Whittaker on the design of seismically
isolated offshore oil and gas drilling platforms in the North
Pacific near Russia's Sakhalin islands, several hundred miles north
of the epicenter of the March 11th Japanese earthquake.
"These platforms sit on concrete bases on the ocean floor with
legs that are about 80 meters tall, and the structure on top of the
platform is another 20 stories high; the entire structure weighs
some 30,000 tons," he explains.
"Conditions there are extreme," he continues. "It is a
multi-hazard environment, where one hazard can worsen the effects
of another. The platforms are designed to withstand, without
failure or significant effect, major earthquakes, ice forces on
platform legs where giant slabs of ice two meters thick can form,
temperatures as low as -40, blasts and very large waves, on the
order of 10 meters above the ocean's surface, which only may occur
once every 10,000 years, and waves in combination with ice slabs,"
he says. "They are very difficult structures to design."
The offshore platforms, about 100 meters by 100 meters in plan
dimensions, sit on four friction pendulum bearings, each of which
has the capacity to safely carry 13,000 tons. The friction pendulum
bearings allow structures to respond to strong earthquakes by
swinging gently from side to side, like a pendulum, minimizing the
risk of damage to the structure and the people who work inside
it.
Constantinou says that the bearings, made of steel ductile to
very low temperatures and which have a large displacement capacity
and a capacity to carry such large loads, are the only ones
suitable for the extreme conditions encountered in the North
Pacific.
"It wouldn't be possible to use elastomeric – rubber --
bearings, which are very frequently used in Japanese buildings,"
Constantinou explains. "At those very low temperatures, the rubber
bearings become brittle and can shatter like glass. Also, these
loads and displacement demands are too large for elastomeric
bearings."
UB faculty often travel to countries and regions devastated by
earthquakes, as part of international efforts to improve seismic
design of buildings and infrastructure. Disaster mitigation,
response to extreme events and multi-hazard engineering are
research strengths of the university identified in the UB 2020
strategic plan.
Founded in 1986, MCEER, headquartered at the University at
Buffalo, is a national center of excellence in advanced technology
applications dedicated to reducing losses from earthquakes and
other hazards, and to improving disaster resilience. One of three
such centers in the nation established by the National Science
Foundation, MCEER has been funded principally over the past two
decades with more than $67 million from NSF, more than $47 million
from the State of New York and more than $34 million from the
Federal Highway Administration. Additional support comes from the
Federal Emergency Management Agency, other state governments,
academic institutions, foreign governments and private
industry.
The University at Buffalo is a premier research-intensive public
university, a flagship institution in the State University of New
York system and its largest and most comprehensive campus. UB's
more than 28,000 students pursue their academic interests through
more than 300 undergraduate, graduate and professional degree
programs. Founded in 1846, the University at Buffalo is a member of
the Association of American Universities.