Chapter Meeting Sept. 16 at UC Berkeley, Hearst Mining Building
Loma Prieta Commemorative Symposium, Oct. 17 at Mark Hopkins Hotel, San Francisco
Chapter Meeting Nov. 18, location TBD
ATC & SEI conference on seismic performance of existing buildings, Dec. 9-11, San Francisco
We hope you enjoy the summer edition of EERI Nor-Cal's quarterly newsletter.
Letter From the President
This is the second quarterly newsletter from the Northern
California Chapter of EERI. We received a number of comments from members after
the first newsletter. Your ideas and suggestions are welcome, so please keep
Chapter meetings will resume after the summer holidays.
Please mark your calendars for the Sept. 16 and Nov.18 meetings described later
in this newsletter and join us for professional growth, visiting with old
friends and meeting new people. We hope you attend.
There are two chapter activities I would like you to
consider joining. The first, our chapter school safety committee, is helping
schools prepare for earthquakes. Our approach incorporates awareness,
preparedness, abating falling hazards and building structural safety. See Tom
Chan's article for more details.
The second, the Concrete Coalition
continues to build a database of older concrete buildings in northern
California cities with the help of our Chapter, SEAONC members and other
volunteers. Already, we've learned many lessons in the process of evaluating
the risks to our communities from older concrete buildings. You can help by
volunteering a few Saturday mornings to survey your community. This is a first
step in helping owners and our communities understand the consequences of
earthquake damage to these types of buildings. Your help would be appreciated.
Contact Dave McCormick
Several activities are underway as part of the upcoming 20th
anniversary of the Loma Prieta earthquake. I strongly encourage you to attend
the Oct. 17 Loma Prieta Commemorative Symposium described later in this
newsletter. Also, the Chapter is part of a large consortium of Bay Area Earthquake
Alliance organizations that will participate in an earthquake drill on Oct. 15
called The Great California ShakeOut
The anniversary and the ShakeOut are
opportunities for you to discuss earthquake safety with you family, friends and
colleagues. It is the time to freshen your supplies and update your emergency
plans. In coming months, we will
provide more information on commemorative activities and steps you can take as
a leader in northern California earthquake safety.
President, EERI Nor-Cal
Lessons From the
By Khalid M. Mosalam
This April a magnitude Mw=6.3 earthquake struck
the central region of Italy
near the city of L'Aquila.
While the earthquake was tragic--305 people killed, 1500 injured and thousands
of buildings destroyed--its aftermath provides lessons for earthquake
professionals in the Bay Area.In the town of Onna, a URM building is severely damaged
Within 10 km of the epicenter, the recorded horizontal peak
ground acceleration exceeded 0.35g, and the ground shaking had high-frequency
content with relatively short duration. The damage indicated strong effects of
site conditions, and heavy damage occurred in structures founded on young
Old unreinforced masonry (URM) buildings made of mortar and
multi-wythe rubble-stone or clay bricks were significantly damaged. These
buildings were typically two to three stories tall, and the damage ranged from
wall cracking to severe damage and collapse. Some buildings with retrofitted
cross-ties to reduce out-of-plane wall deformation performed reasonably well
with limited cracking and no out-of-plane collapses.
Reinforced concrete (RC) buildings ranged from two to eight
stories tall. The majority of modern RC buildings were designed for horizontal
acceleration of about 0.25g. In the epicentral region, little attention was
paid to ductility requirements (e.g. the use smooth reinforcing bars, short lap
splices, and insufficient column ties and transverse reinforcement in
The designs appear to have ignored the effect of infill
walls, and some construction material was of poor quality. Although these deficiencies
are serious, the wide-spread damage more likely resulted from a lack of
ductility and the brittleness of exterior infill walls and interior partitions.
There were also isolated cases of RC frame damage due to shear failures that
led to soft story mechanisms.
In the town of L'Aquila, beams fail due to inadequate steel reinforcement
The following three major lessons can be drawn from the
1) Cross-ties restraining out-of-plane deformation of
multi-wythe URM walls are effective in limiting the collapse of these types of
2) Infill walls may protect seismically-deficient RC
frames and reduce their damage. But the damage in URM infill walls is
hazardous, and these types of walls should be used with care and properly
considered in the design.
3) Out-of-plane failure of infill walls should be
accounted for in the design process of RC frames with URM infill walls.
Moreover, the in-plane/out-of-plane interaction should be considered in the
designs of RC frames with URM infills.
Khalid Mosalam is a Professor and Vice Chair in the Department
of Civil and Environmental Engineering, University
of California, Berkeley.
By Tom K. Chan, Chair, EERI Nor-Cal School Safety Committee
AB300 directed the state's Department of General Services to inventory public
school buildings for earthquake safety. The study focused on non wood-framed (higher
hazard) buildings that represented about 20% of the total square footage of California's public
schools, and results of the study
were published in 2002. From the survey, 7,537 buildings were classified as higher
seismic risks. But the study's findings were not well publicized and soon faded
from public attention.
Results from the inventory of public school buildings for earthquake safety.
The M7.9 May 2008 Sichuan, China, earthquake killed over 15,000 children
and refocused attention on California
school earthquake safety. A number of news articles soon appeared, including in
the San Francisco Chronicle
, Oakland Tribune
and Marin Independent
Journal. All pointed to the AB300 list and lack of action.
school funding has been an ongoing problem, even before the current state
financial crisis. Asking schools to come
up with seismic retrofit funds is difficult.
The goal of EERI's NC School
Safety Committee is to educate school administrators and teachers and help high
seismic risk schools reduce their risk and minimize life loss in a big
earthquake. We hope to do this through a combination of outreach programs, risk
surveys, emergency planning assistance, disaster response training, and
self-help equipment anchorage programs. The committee is developing a resource
list of volunteers for the following activities:
· Structural engineers to conduct risk surveys of northern
Californian schools to identify structural and nonstructural seismic risks.
· Emergency planners to update emergency plans.
· CERT Trainers to teach emergency response to
· Engineers to develop an equipment anchorage
training manual for public schools.
If you are interested in helping with any of the above
activities, please email me at email@example.com
and provide the following information: your contact information, the activity
you want to volunteer for, and your field of expertise. The email subject line
should be: EERI schools volunteer - your
name. Thank you.
Chapter Meetings and Other Important Events
● September Chapter Meeting
16, UC Berkeley, Hearst
Seismic Design Guidelines for Tall Buildings in California" presented by Jack Moehle, Professor of Civil and Environmental Engineering, UC Berkeley
chapter for a preview of the New Seismic Design Guidelines for Tall Buildings,
the first to include design criteria and guidance for seismic designers and
reviewers of tall buildings with industry-wide consensus. These guidelines are
expected to be developed into code documents in the future.
● Loma Prieta Earthquake Commemorative Symposium
17, Mark Hopkins Hotel, San Francisco
will discuss the effects of the Loma Prieta earthquake,
as well as the tremendous strides that have been made in the past 20 years to
make our cities and lifelines safer. They'll also look ahead and consider where
earthquake professions might be heading over the next 20 years.
● November Chapter Meeting
18, Location TBD
Early Warning Systems & A Northern California
Case Study" presented by Richard Allen & Jim Goltz
Richard Allen of the UC Berkeley Seismological
Labs discuss his research on early earthquake warning systems and how they
might mitigate risk. Social scientist Jim Goltz will follow
up on how these systems could affect the response and risk
reduction strategies of policy makers and social scientists in Northern California.
● ATC & SEI Conference:
Improving the Seismic Performance of Existing Buildings and Other Structures
inaugural conference will focus on exchanging new information on the seismic
evaluation and strengthening of existing buildings and other structures.
Presentations will include case studies, new discoveries, innovative use of new
technologies and materials, shortcomings of existing standards, and
If you are interested in contributing an article or announcement in an upcoming edition of The Quarterly Shake, please contact the editor, Justin Moresco