World’s Largest Outdoor Shake Table Tests How Buildings will Perform During Earthquakes

 

Commission Grantee UC San Diego

UC San Diego Uses Largest Outdoor Shake Table to Test Steel Frame Construction

 

Earthquakes cause shaking motions than can, if intense enough and of sufficient duration, damage buildings and other structures. But buildings and earthquakes have a complicated interaction, and understanding how different structures will respond to different kinds of earthquakes requires testing. And if the building is large enough a big shake table to test it is required.

The largest outdoor shake table in the world is in San Diego. Operated by the UCSD school of Engineering, it is big enough to support a six-story building and shake it with the same force as the Northridge Earthquake, burn part of it, and then shake it again.

This kind of research supported by the California Seismic Safety Commission insures that the buildings we construct will be safe to occupy, saving lives and property in the event of an earthquake (demonstrated here http://cfs-research.ucsd.edu/index.html in numerous videos).

https://www.youtube.com/watch?v=joO4zP0ukms

https://www.youtube.com/watch?v=6z4qMOZiUbsh

Learning Post Earthquake Economic Recovery Lessons from Japan

 

Commission Grantee – San Jose State University

Learning from Japan – Improving post-earthquake economic recovery

 

Japan is, like California, located along the “Ring of Fire” and subject to frequent earthquakes.  Japan was one of the first nations to build an earthquake early warning system (EEWS) and it is used and trusted.  In the past decade Japan has experienced numerous earthquakes, but the Great Tohoku Earthquake and Tsunami of 2011 and the Great Hanshin (Kobe) earthquake of 1995 had devastating impacts on the people and industry that experienced strong shaking.

Since the Tohoku Earthquake experience, the Japanese national and local governments implemented numerous measures to help drive the recovery, and growth, of affected businesses.  This provides an opportunity to learn from the experience of the Japanese to identify post-earthquake economic recovery measures that could apply to California.

The Seismic Safety Commission has partnered with San Jose State University to work with Japan affiliated California businesses to learn from the experiences of their Japanese parent firms and partners, in an effort to accelerate California’s post-earthquake economic recovery. This project consists of a survey of the recovery measures implemented by the Japanese governments, and if available, learn how effective these measures have been.  It will also include surveying California firms with Japanese affiliations to determine their perceived needs for earthquake recovery assistance.

This project also includes seminars for Japanese companies in northern and southern California to educate them on the earthquake threat in the State. These seminars will also cover the regulations designed to accelerate economic recovery and information on US federal, state and local programs that can assist their businesses.

Together with other programs the Commission has sponsored, such as that with the California Small Business Development Commission, this work will help inform the development of a broad business/economic recovery strategy for the State of California.

 

 

The Tall Buildings Initiative

Commission Grantee – Pacific Earthquake Engineering Research Center (PEER)

Tall Building Initiative – Insuring New Building Technologies Are Safe

 

Compare photos of the skylines of San Francisco or Los Angeles from the 1970s with photos today and you will notice that buildings are taller, a lot taller. Many of the newer tall buildings are mixed use, including residential units. We take for granted that these are safe in case of earthquake, but are they? The materials and construction techniques used today are new and we hope improved, but we are putting new stresses on the buildings as they rise and the land they are built upon.

The Seismic Safety Commission, together with other funders, has sponsored work on Tall Buildings by the Pacific Earthquake Engineering Research Center (PEER), which has recently released some of its recommendations. Peer is a cooperative research center with researchers from over 20 universities and private sector firms working together to improve building safety and promote appropriate public policy.

In the early stages of the Tall Building Initiative, PEER conducted research into perceptions by key stakeholders (governments, owners, builders, etc.) and found the following:

  • “Stakeholders were surprised by, and not necessarily accepting of, current code performance expectations for normal buildings.
  • Stakeholders strongly advocate disclosure of risks and anticipated performance, including serviceability and fire risks.
  • Most believed that a higher standard should be required for tall buildings.”

Based on this input and its extensive background and experience, PEER developed a set of recommendations which are included in PEER Report No. 2017/06 titled: “Guidelines for Performance-Based Seismic Design of Tall Buildings V 2.03.” This new version of the PEER Guidelines addresses lessons learned since the earlier version, based on updates from “many projects and the conditions, knowledge, and state-of-practice that presently exist.” Not necessarily an easy read for the general public, this report contains valuable information for those responsible for building safety.

 

Key Findings from the “Back to Normal” Project

 

Commission Grantee Global Earthquake Model Foundation (GEM)

Key Learnings from “Back to Normal” Research

The Back to Normal research and model funded by the Commission and produced by GEM and UCLA was described in an earlier Post. Here we review some of the key findings, based on a study of the 2014 South Napa earthquake. The Back to Normal study looked at what factors influenced recovery from earthquake damage. GEM listed eight key variables that influence rapid and effective recovery: These variables are listed below in order of importance, with the level of damage being the most significant factor.

  1. Level (or amount) of building damage
    b. Homeownership
    c. Percentage of households that have a male householder
    d. Presence of health insurance coverage
    e. Employment status
    f. Percentage of households that have any type of available income
    g. Percentage of buildings constructed after 1950 (a result of updated building codes; consequently, these structures suffer less damage during an earthquake)
  2. Percentage of English-speaking households

The percentage of homes insured for earthquake was low in Napa and, therefore, not a factor in this scenario, but access to financial resources clearly impacts recovery.

Based on their findings, the GEM team created several recommendations, many of them aimed at future research and improving the accuracy and effectiveness of the modeling effort. But some were specifically targeted at how to improve the recovery effort and speed the return to normal. On page 12 of the 85-page report, they recommend the following:

  1. “Facilitate access to assistance for vulnerable groups of the population, such as residents that do not speak English.
  2. Conduct further investigations into the relationships between the variables that correlate most positively with recovery (e.g., homeownership and health insurance) to determine the underlying causes.
  3. Conduct more extensive research on cost-benefit analysis of retrofitting buildings because the buildings not seismically designed in the city of Napa sustained significantly more damage compared to stronger structures.
  4. Improve access to financial mechanisms, such as earthquake insurance, to residents exposed to high earthquake risk, as well as investigate and promote alternative post-earthquake resources, such as grants, which will support residents in the rebuilding process.”

Many people do not realize that the typical homeowner’s policy does not cover earthquake loss. The California Earthquake Authority (CEA) is a not-for-profit organization that provides residential earthquake insurance for Californians, and the report recommends more people take advantage of their programs and policies.

 

“Back to Normal” – Earthquake Recovery Modeling Tool

 

Commission Grantee Global Earthquake Model Foundation (GEM)

GEM Team Develops “Back to Normal” Earthquake Recovery Modeling Tool

 

The prediction of earthquakes remains an unrealized goal of the scientific community, but we now have a tool that will help civic leaders and others better plan for successful recovery efforts. To better understand some of the main factors that influence earthquake recovery, the Alfred E. Alquist Seismic Safety Commission supported work by the Global Earthquake Model Foundation (GEM) and UCLA to develop a software tool to help estimate how long it would take to recover from an earthquake and what socio-economic factors might influence recovery.

The output of this Commission supported work is “Back to Normal” and the full report can be found on the Commission’s website. Building on over $20 million in funding that has been used the develop the Open Quake software package and supporting datasets, Back to Normal used data from the 2014 M6 South Napa Earthquake and the City of Napa to create this real-world case study and report. It estimates how long it will take an affected area to recover from a similar earthquake and what socio-economic conditions impact the recovery time and trajectory.

While not all earthquakes are the same, this tool will help civic leaders plan and direct resources where most needed to help the community recover.

 

 

A Network for Multi-hazard Monitoring and Warning

Commission Grantee UCSD/SIO HPWREN

Leveraging a Network for Multi-hazard Monitoring and Warning

 

In 2000 the National Science Foundation funded the Supercomputer Center at UCSD to deploy HPWREN, the High Performance Wireless Research and Education Network. This network provides network support for cameras and sensors in the field on a wireless system spanning San Diego County and beyond, enabling seismic, acoustic, weather, and fire monitoring via a mix of sensors and cameras. Video and weather from the network is available in near real time at http://hpwren.ucsd.edu and seismic data is available at http://anf.ucsd.edu/events. The network currently covers most of San Diego County and much of Imperial County and has extensions into Riverside County. It has wireless backbone speeds up to 200+ megabits per second, fast enough for high-definition 4K video.

This mix of seismic, weather, and fire monitoring technologies mirrors that provided by the Seismology Lab at the University of Nevada, Reno (UNR), (http://www.alertwildfire.org/tahoe/) and researchers from UNR and UCSD/SIO have partnered for years on improving technologies that can help save lives. In fact, the UNR system in Lake Tahoe and Nevada has been credited with the early detection of more than 300 fires in the region over the past two years.

These two teams have pioneered the use of robust radio networks for multi-hazard monitoring.  Leveraging the high fixed cost of the towers and radio equipment to support earthquake, fire, and other risks lowers the cost for each of the different warning systems and enables larger, and more resilient, systems to be deployed. Given the recent wildfires in California and our investment in separate seismic and fire warning systems, it is a good model to consider for the State.