MCEER/UB Engineer Helps Develop Unique Design To Seismically Modernize New
Airport Terminal In Istanbul
Release date: Thursday, January 6, 2000
at (716) 645-5151
Buffalo, N.Y. --
It won't be apparent to passengers landing on the January 6 inaugural
flight at Istanbul's brand new international airport, but the roof of the
massive terminal building features a unique approach to seismically modernizing
the structure following last summer's devastating quake.
The massive, 800 foot-long by 500-foot-wide roof is the first to feature both the
ability to respond to seismic forces as a single, structural unit and the ability to
expand and contract in response to exposure to the sun.
The conceptual designs for seismic modernization of the airport were developed
by Michael C. Constantinou, Ph.D., professor and chair of the Department of Civil, Structural and Environmental
Engineering, University at Buffalo and a researcher with the Multidisciplinary
Center for Earthquake Engineering Research (MCEER), and colleagues
at the University of California at Berkeley and LZA Technology of New York
City, the consulting engineers retained to modernize the structure following
the magnitude 7.4 quake.
"The structure had only sustained minor damage during the earthquake," said
Constantinou, "but considering the certainty with which they expect another
large-magnitude earthquake with an epicenter closer to the airport, the desire was to
improve the performance level of the structure to one that ensures the safety of people
inside, and even beyond that." The airport was under construction at the time of the
quake, which was the main reason it sustained the damage, Constantinou explained.
"Since repairs had to be made, it provided the opportunity to seismically
modernize," he said.
additional article, Turkey's Terminal Goes
Seismic, on this topic appears in enr.com, the web site of Engineering News
According to Constantinou, the third-story columns that support the roof were the most
vulnerable link in the existing structure. The objective was to reduce earthquake forces
on both the supporting columns and roof. To increase the building's performance level, he
added, the engineers had two options. "Either we could increase the strength of the
building or we could reduce the seismic demand on it, which is not easy to do," he
said. "We decided we had to do both."
scheme consisted of three steps: increasing the strength of the second- and
third-story columns by steel-jacketing the columns, seismically isolating
the roof to reduce seismic demand on third-story columns and installing "lock-up
devices" at roof expansion joints.
The design by Constantinou and his colleagues involved slicing the columns horizontally
at the top and installing "friction pendulum" devices manufactured by Earthquake
Protection Systems of Richmond, Calif. These devices, which were tested extensively at UB,
are designed to allow structures or structural components to swing gently from side to
side, like a pendulum.
"This has not been done before," said Constantinou. "What we did was to
tie together the segments of this 800-foot-long roof together as they sit on top of these
isolation devices. This gives the roof the ability to 'swing' as much as 12 inches with
respect to the columns during an earthquake, thus protecting the columns." At the
same time, the roof's direct exposure to the sun necessitated the use of expansion joints
that could accommodate thermal movement without inhibiting seismic protection.
The solution came in the form of "lock-up devices" manufactured by Taylor
Devices, a Western New York firm that has had a long collaboration with the UB Department
of Civil, Structural and Environmental Engineering and MCEER. Now, instead of having a
rigid connection between the roof and the columns, the segments of the building's roof
will stay flexible in response to thermal forces, while at the same time featuring an
ability to "lock up" as one piece when subjected to earthquake forces. Once
activated by seismic activity, the lock-up devices essentially override the expansion
joints, allowing the roof panels to respond as a single unit. This system, as well as the
friction pendulum devices, was extensively tested and optimized through collaborations
with UB and MCEER.
Constantinou's team was assembled by LZA Technology, which was under contract to the
Turkish developer TEPE-AKFEN-VIE and the construction consultant Turner International of
New York City to seismically modernize the airport structure.