Joyce Fuss, SE, SECB, LEED AP, Lionakis Associate & SEAOC President 2018-2019
The timing of this post couldn’t be at a more fitting seismic moment, given the recent M6.4 and M7.1 earthquakes that took place in Searles Valley, CA earlier this month. We are thankful that there has been no loss of life and limited damage to structures due to this significant event, and our member organization in Southern California, SEAOSC were immediately involved in the event response. You can see those details and a video of the press conference here.
Know that SEAOC and affiliated organizations worked diligently on a recovery plan that is now being put to the test. More information to come on that plan and its on-the-ground implementation will be available in my next post and in the meantime you can keep up-to-date on the latest developments and action at SEAOSC here.
Now, onto our usual updates to all as we move into the summer season with the 2019 SEAOC Convention just around the corner! Registration opened early last month and we are looking forward to hosting you at the beautiful Squaw Creek Resort near Lake Tahoe. The convention will include an amazing collection of technical and practice-related presentations including the Blue Book and SE3 topics as well as innovative projects and a business track. You can check out the latest information on the website.
Convention time is also a great time to squeeze in a few extra days to experience the majesty of the Sierra Nevada range and the largest alpine lake in North America. Please be sure and join us!
I also must share here some timely background on a quote by me that appeared recently in the New York Times regarding why we “don’t build stronger or more earthquake resistant buildings in the US,” with a comparison to Japan where base-isolated buildings are common. My main point is that there is much more to this conversation than is initially apparent, and my message includes the fact that although earthquakes occur far less often in California (and other parts of the United States), the disruption to our state will be incredibly significant when the next seismic event occurs. Loss of infrastructure and housing, economic losses, displacement of residents and influx into areas outside the affected region will have a lasting impact and the recovery will take longer than we can imagine. As a society we are asking the question “how we can build stronger and more resilient structures and be better prepared for the next big earthquake.” The time to answer this question is now, because we cannot afford to wait until the next “big one” occurs and the devastation forces us into a lengthy and costly recovery period.
SEAOC is involved in initiatives to push forward the concept of Functional Recovery. The Big Idea is to design and build structures that can be occupied immediately or soon after a major earthquake, which would limit disruption and shorten recovery time as well as reduce restorative costs. Current codes have evolved over the last several decades to do an excellent job of saving lives and limiting damage enough to allow people to get out of buildings after a design basis earthquake (and maintain Life Safety in a Maximum Credible event). Functional Recovery could mean that structural damage is prevented or limited to be easily and quickly repaired, and non-structural damage is also limited and repairable.
SEAOC is making important progress towards this goal through the sponsorship of legislation – California AB 393 – which establishes a functional recovery working group comprised of state entities and members of the construction and insurance industries to explore the concept and investigate the practical means of implementing a standard for it. SEAOC is included in the working group, thereby preserving our future through disaster resilience/preparedness and the creation of resources to further this initiative. SEAOC will also be working to craft a proposed definition for Functional Recovery in a working group with EERI over the next several months, and then continue working to set goals for the development of tools to achieve this design level.
Additional Clarifications and Considerations
As a society we are having the difficult conversations about the impact of natural disasters on our man-made environment and are questioning the approaches we have used in the past, however advanced these may be. The mindset is shifting from a life safety approach towards preparedness and preserving the built environment, a more sustainable and resilient approach. Some have used the term “throw-away” buildings to describe the previous philosophy towards seismic design, which is a strong term (think “wake-up call”) but unfortunately will end up being the case for many, especially in communities located in high seismic risk areas.
The cost to design and build structures that are more resilient in the event of an earthquake is not as much as some would have us think, and any additional cost will be quickly and summarily dwarfed by the cost of repair or re-building. If we think about the cost of the structural components of a building (say 15% to 25% for discussion purposes here) and that the seismic force-resisting components are a portion of that (let’s just use a conservative 50% for this conversation) and let’s say to increase the strength of the seismic system to a functional recovery is somewhere in the range of 25% to 50% of that seismic system. At the most, the additional cost for a structure that can survive a design basis seismic event (earthquake) and not require major structural repair or demolition (remain intact) could be in the ranges of 6% of the overall building cost (or as little as 2% to 3%). Is it worth the price for a business or homeowner to be able to get back into a building and greatly reduce recovery time and cost?
There are many ways to design and construct buildings for earthquake resistance. Base isolation is one good method to reduce the response and forces in a structure, but other systems available include in-line viscous dampers (essentially shock absorbers for buildings), modular elements that can be easily installed into the building frame, and systems with removable “fuse” components that can be removed and replaced after an earthquake without tearing the entire structure down.
Engineers have many options available for resilient design, and more methods and products are becoming available every year. We essentially have a kit of tools from which to choose, and new ones to acquire as the movement towards resiliency continues to grow. This forward thinking is on an exponential trajectory.
*This newsletter has been modified from its original posting which can be found on the SEAOC website in full.