The Quarterly Shake
EERI Nor-Cal Logo
News, updates and announcements from EERI Nor-Cal
Summer 2009
In This Issue
Important Dates
Letter From the President
Lessons From the Abruzzo, Italy, Earthquake
School Safety Committee Update
Chapter Meetings and Other Important Events
Important Dates

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

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We hope you enjoy the summer edition of EERI Nor-Cal's quarterly newsletter.
Letter From the President

               Tom Tobin           
  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 them coming. 

  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: Dlmccormick@sgh.com or 415-343-3023.

  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.
 
Tom Tobin
President, EERI Nor-Cal Chapter
415-380-9142
Lessons From the Abruzzo, Italy, Earthquake

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.

Damaged URM building in town of Onna
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 sediments.
 
  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 beam-column joints).

  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.

Beams fail due to lack of reinforcement
 In the town of L'Aquila, beams fail due to  inadequate steel reinforcement

  The following three major lessons can be drawn from the earthquake:
 
1)  Cross-ties restraining out-of-plane deformation of multi-wythe URM walls are effective in limiting the collapse of these types of buildings.

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.
School Safety Committee Update

By Tom K. Chan, Chair, EERI Nor-Cal School Safety Committee
 
  California's 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 of survey of California schools
 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.
 
  California 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 school staff.
  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 tchan@miyamotointernational.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
Sept. 16, UC Berkeley, Hearst Mining Building
"New Seismic Design Guidelines for Tall Buildings in California"  presented by Jack Moehle, Professor of Civil and Environmental Engineering, UC Berkeley
 
  Join the 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
Oct. 17, Mark Hopkins Hotel, San Francisco
 
  Speakers 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
Nov. 18, Location TBD
"State-of-the-Art Early Warning Systems & A Northern California Case Study" presented by Richard Allen & Jim Goltz
 
  Come hear 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
Dec. 9-11, San Francisco
 
  This 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 socio-economic issues.
  If you are interested in contributing an article or announcement in an upcoming edition of The Quarterly Shake, please contact the editor, Justin Moresco.