Transparent Seismic Mitigation for Community Resilience (Abstract)
by Chris D. Poland, SE
Chris D. Poland, SE (2008). Transparent Seismic Mitigation for Community Resilience (Abstract). SMIP08 Seminar on Utilization of Strong-Motion Data, p. 59 - 61.
Healthy communities continuously grow by leveraging their intellectual capital to drive economic development while protecting their cultural heritage. Success, in part, depends on the support of a healthy built environment that is rooted in contemporary urban planning, sustainability and disaster resilience. In many parts of the country, the ability to rebound from major earthquakes is an important facet of community health, one that depends on the expertise of the nation’s earthquake professionals. We, as earthquake professionals, have the responsibility to deliver that expertise in an understandable fashion that can be interwoven into public policy while recognizing the community’s natural ability to rebound. No one else has the technical knowledge to bring that perspective to the policy table.
Earthquake professionals -- Emergency Response Planners, Earth Scientists, and Earthquake Engineers -- have made great strides toward understanding how to record, characterize, build for, and recover from major earthquake events. Today’s seismic hazard maps, performance based building codes, and integrated emergency response plans all demonstrate remarkable progress in just the past 30 years. Seismic hazards nationwide are understood and procedures are available to adequately predict performance. EERI’s Securing Society Against Catastrophic Earthquake Losses defined a research and outreach plan in 2003 that would arrest the growth of seismic risk nationwide to acceptable levels. In 2006, EERI, SSA, and California OES co-convened a conference commemorating the 1906 San Francisco Earthquake and published Managing Risk in Earthquake Country; an action plan for reducing losses, to acceptable levels in future earthquakes. Unfortunately, progress on implementing these plans appears to be stalled due to a lack of funding and political will caused by complacency, misunderstanding, and an absence of persistent lobbying by the earthquake experts.
Planners and policy makers are deeply concerned with all aspects of their communities, including its seismic safety. Their reluctance to implement the latest plans for achieving seismic safety is rooted in a misunderstanding of the hazard they face and the risk it poses to their built environment. Probabilistic lingo and public debate about how big the “big one” drives them to resort to their own experience and intuition. “It’s never happened here before” is a common justification for setting aside policy changes that will improve safety and resilience. The usual misconception of how much damage the built environment will experience is based on the belief that the building official and their latest building codes assure protection in damage proof buildings. There is a fundamental lack of transparency related to what is expected to happen and it is partially blocking the policy changes that are needed.
The solution: craft the message in broad based, usable terms that name the hazard, defines performance, and establishes a set of performance goals that represent the resiliency needed to drive a community’s natural ability to rebound from a major seismic event.
With the assistance of the local earthquake professional community, urban planners, policy makers, and local City officials, the San Francisco Planning and Urban Research Association (SPUR) has established three study groups to sort out the issues. We are in the process of determining options and developing policy recommendations to assure that San Francisco and the Bay Area will not fall to the dilemmas that are preventing the restoration of much of the Gulf Coast after Hurricane Katrina. SPUR, in its usual role as an advocate for thoughtful Urban Planning, choose to take a different tack than has been used in the past. We are using transparent goals and measures with an intuitive vocabulary for both performance and hazard, and the recommendations describe a state of resiliency that is needed to support response and recovery.
SPUR is in the process of defining performance goals, for the built environment in terms of three time frames. The first relates to the initial response and lasts seven days. The second extends to 30 days and focuses the restoration of workforce housing and meeting ongoing social needs. The third is a three-year period of long-term reconstruction. During the initial period, essential facilities such as hospitals, police stations, and emergency response facilities are needed, along with housing that can support shelter-in-place, and the infrastructure systems needed to support reconstruction. The focus of the next period is on restoring the living environment for the workforce that will reconstruct the city, by reestablishing their utilities, schools, and neighborhood businesses. The third phase expedites the achievement of a “new normal”.
SPUR is in the process of defining the hazard in terms that are consistent with current San Francisco programs and policies. Three earthquakes are named and defined for use in the recommendations. The “routine” earthquake is a 70% in 50-year event and used to define the service levels of tall buildings. The “expected” earthquake is a 10% in 50-year event and is used as the basis for the policies related to performance. The third is the “extreme” earthquake that is a 2% in 50-year event, the basis of the 2006 International Building Code.
SPUR is defining five performance measures for buildings and three for lifeline systems in an effort to establish an intuitive understanding of the expected post-event performance. Each declares whether people will be safe inside, whether the building will be able to be repaired and whether usable during repairs. Lifeline systems are further defined in terms of the time intervals to restore 90%, 95%, and full service. These transparent categories are used in conjunction with the expected earthquake level to describe the standards needed for new buildings and lifelines and the rehabilitation programs needed for existing buildings and lifelines so that the performance goals are achievable, the cultural assets protected, and the economy able to rebound. Because the definitions apply to individual types of uses of buildings and allow various time frames for restoration, the needed programs should prove to be achievable and cost effective.
Many of us strive to contribute to the greater good while doing our everyday jobs. It is a passion for me and has lead to my personal devotion to seismic risk reduction advocacy nationwide. As earthquake professionals, we are very lucky to be able to contribute an expertise that can save lives as well as communities. In 30 plus years, I’ve learned that I can be effective when working with other structural engineers on buildings codes, pace setting when working with the larger family of earthquake professionals, and actually able to change public policy when providing my technical expertise to the broader community of policy makers while helping them craft the policies needed to instill change. It takes patience and a broad understanding of all the issues being faced. It’s not unlike my trade, fitting a structure into a building. Here it is fitting seismic into my community and the results are worth the effort and frustration. I challenge each of you to do the same. Volunteer and work toward making your community healthier.