Pictures, etc
pdf file of Lecture announcement
The Dongju Lee Memorial Lecture
Department of Civil Engineering and Engineering Mechanics
Columbia University
New York City
Liquefaction of Fine-Grained Soils and Its Effects on Buildings
Prof. Jonathan D. Bray
Department of Civil and Environmental Engineering
University of California, Berkeley
March 10, 2005 (Thursday)
5:00-6:30 pm
Davis Auditorium, CEPSR
Abstract: Ground failure in Adapazari, Turkey
during the 1999 Kocaeli earthquake was severe.
Hundreds of structures settled, slid, tilted, and collapsed due in part
to liquefaction. The soils that led to
severe building damage were generally low plasticity silts. A comprehensive investigation was completed
to understand the effects of subsurface conditions on the occurrence of ground failure
and its resulting effects on building performance. The CPT was able to identify thin seams of
loose liquefiable silt, and the SPT (with retrieved samples) allowed for
reliable evaluation of the liquefaction susceptibility of fine-grained
soils. State-of-the-practice CPT- and
SPT-based liquefaction triggering procedures adequately identified soils that
liquefied only if the Chinese criteria were disregarded. Field observations and cyclic tests show that the Chinese criteria
are not reliable for determining the liquefaction susceptibility of
fine-grained soils. Soils that liquefied
did not typically meet the clay-size criterion of the Chinese criteria. It is not the amount of “clay-size” particles
in the soil; rather it is the amount and type of clay minerals that best
indicate a soil’s susceptibility to liquefaction. The soil’s plasticity index is thus a better
indicator. A new liquefaction susceptibility criterion for fine-grained soils
is proposed based on the results of this field and laboratory testing program.
The Dongju Lee Memorial Lecture was
established with a generous contribution from the Lee Family. We would like to express our
gratitude to DJ's father, Prof. Yong-won Lee (who is currently the President of
Chinju National University of Education, Korea), for his support in
establishing the Lecture and an Award. DJ, as Dongjupreferred
to be called, passed
away on February 26, 2003 while he was a student working toward the
doctoral degree. He obatined his Master's and Professional degrees from
Columbia University.
more about Dongju Lee
Biographical Sketch of Prof. Jonathan D. Bray
Jonathan Bray is a Professor of Geotechnical Engineering at the University of California,
Berkeley. He earned engineering degrees from West Point
(B.S.), Stanford University
(M.S. in Structural Engineering), and the University of California,
Berkeley (Ph.D. in Geotechnical Engineering).
Dr. Bray has been a registered professional civil engineer since 1985,
and he has served as a consultant on several engineering projects and has
served as an expert geotechnical engineer in several legal cases. Professor Bray has authored more than 150
research publications. His expertise
includes the seismic performance of earth and waste fills, earthquake fault
rupture propagation, seismic site response, liquefaction and ground failure and
its effects on structures, and post-earthquake reconnaissance. He has received a number of honors, including
the Shamsher
Prakash Research Award, ASCE Huber Research Prize, Packard Foundation Fellowship, NSF
Presidential Young Investigator Award, and two North American Geosynthetics
Society awards.