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Current Research Towards Tornado Resilient Communities the Building 2/27/2015 Current Research Towards Tornado April showers bring May showers …. Resilient Communities 5‐10‐1999 5‐08‐2013 5‐20‐2013 David O. Prevatt, PhD, PE … but in Moore, OK …? University of Florida • $4 billion direct economic losses in 15 years • Debris removal costs and lost production [email protected] • Reduced tax base, and lost utility fees to city $2 billion direct economic loss 4,724 destroyed homes & 44 fatalities Research Motivation $2.2 billion direct economic loss 7,900 destroyed homes, 158 deaths What building performance should we expect from improved building codes? Are the Moore’s code changes sufficient and sustainable in the long‐term? What is now needed to leverage current national focus on tornado‐resilience? $2 billion direct economic loss 2,400 destroyed homes & 24 deaths The Building Code Codes are for life safety not property Establishes minimum standards that will allow effective City councils and mayors “absolutely do not and reasonable protection for public safety, health and general welfare, and secondarily for protection of know” about the life‐safety objective & how property as appropriate. damaged a code‐compliant building stock will be in the aggregate, and (they) are unsatisfied Codes regulate: when they do learn of (the expected damage.) • Building design, construction & repair Keith Porter (2014). “Safe Enough? How the Building Code Protects Our Lives but Not • Material quality and performance Our Cities” MMC Mitigation Seminar Series • Building use and occupancy Florida Statutes; CL. 553.72 (Intent) 1 2/27/2015 Who are “We”? What performance do “We” expect? • Stakeholders Stakeholders Public‐at‐Large – Building Officials – Building Professionals • No loss of life? • No loss of life? – General Insurance Companies • The Public‐at‐Large – Federal / State Government • No catastrophic collapse? • No catastrophic collapse? – … etc. • All building remain usable? • All building remain usable? • No building damaged? • No building damaged? …it depends on whom you ask! Vision 2060 Moore’s homes will be tornado‐resilient The Moore of 2060 starts in 2015 • Will the 2014’s building code still be enforced? We establish building performance in 45 years – Or would it have been changed ‐ strengthened? by the choices we make today for the building code and the code improvements over time. • Is tornado building collapse a thing of the past? – Have direct economic tornado losses been decreased? • Do all buildings have safe rooms? – Do fatalities and injuries still occur in tornadoes? Lubbock, Texas, Tuesday Morning, May 12, 1970 Price 10 Cents How did Moore 2015 come about? It started more than 45 years ago 2 2/27/2015 1970 Moore homes of 2015 started in 1970 Building code decisions we made (or failed to make) following the Lubbock, Texas tornado and others determined how the Moore, OK buildings collectively performed in 2013. Minor, J.E., McDonald, J.R., and Mehta, K.C. Tornado: an engineering‐oriented perspective. NOAA‐TM‐ ERL‐NSSL‐82., Norman, OK (USA). National Severe Storms Lab., 1977. 2011 1970 Prevatt, D. O. et al. (2012). Joplin, Missouri, Tornado of May 22, 2011: Structural Damage Survey and Case for Tornado‐resilient Building Codes, ASCE Publications. (http://ascelibrary.org/doi/book/10.1061/9780784412503) 2013 1970 Courtesy: D. Prevatt (2013), Moore, OK 3 2/27/2015 2011 1977 Courtesy: D. Prevatt (2011), Tuscaloosa, AL 2011 1970 THROUGH 2015 IN TERMS OF BUILDING PERFORMANCE WHAT PROGRESS HAS BEEN MADE? Courtesy: D. Prevatt (2011), Tuscaloosa, AL Since 2011 ‐ a realignment of forces • Federal Level – NOAA/ Weather Ready Nation / Storm Prediction Center have re‐doubled efforts to share damage reports. – NIST – recently awarded a $20 M Community‐resilience project to improve nation’s response to natural hazards VISION 2060 – NSF –awarded multi‐disciplinary research projects where engineers and social scientists address solutions together CHANGING CURRENT PARADIGMS • Private Organizations BY TWO RESEARCH EXAMPLES – FLASH and IBHS continue to provide practical solutions – ASCE developed a Tornado Design Guide in Commentary • Public‐at‐Large – Represented by Mayor of Moore, OK are more on board to provide commitments to not repeat past errors 4 2/27/2015 Wind Field Developed for Joplin Tornado from Tree‐Fall Patterns Individual Buildings Assessed during Ground Survey of Joplin Tornado Over 70% of individual observations in Joplin either were in agreement For the homes designed to 115 mph (ASCE 7‐10)…. or within 1 EF range of the predicted wind speeds using tree‐fall data. 2,800 ft …… most performed well below 115 mph (white region) If instead homes were designed to 135 mph (EF2) instead.…. AN ENGINEERING‐BASED CATASTROPHE MODEL TO PREDICT TORNADO DAMAGE 2,000 ft Principal Investigators David O. Prevatt, Kurtis R. Gurley Associate Professor, University of Florida Research Assistants Xinlai Peng, David B. Roueche …. reduce the EF2 level damage (white region), narrow the damage Graduate Student, University of Florida 5 2/27/2015 Validation using Joplin Tornado Target Start Point C Predicted vs Observed Damage AB D Predicted Observed Damage E Damage R2W House 2 D B A C E House 2 • Degree of Damage (DOD): 4 • EF Rating: 1 A C • Distance from Tornado Center: 1000 ft B D E Summary Where do we want to be in 2060? • Building codes ought to reflect a collective Building codes address one building at a time. agreement of what’s acceptable in society Today’s codes will produce the 2060 building stock. • Technology isn’t the block –it is commitment • The public must be more engaged early in the Who will turn the ship? process and educated of real costs to them • Implications of building code on future tornado performance is critical to share with the public • Intangible benefits –“i.e. suffering avoidance” must be considered in building code decisions @davidprevatt2 Where do we want to be in 2060? Building codes address one building at a time. Today’s codes will produce the 2060 building stock. Who will turn the ship? @davidprevatt2 6 2/27/2015 Minimum ASCE 7‐10 Design Wind Speeds (0.00143 Annual Probability of Exceedance) ASCE 7‐10, Figure 26a: Basic Wind Speeds for Occupancy Category II Buildings and Other Structures First National Bank Building Lubbock, TX May 11, 1970 Minor, J.E., McDonald, J.R., and Mehta, K.C. Tornado: an engineering‐oriented perspective. NOAA‐TM‐ ERL‐NSSL‐82., Norman, OK (USA). National Severe Storms Lab., 1977. 7 2/27/2015 Tree‐Fall Patterns in the 22 May, 2011 Joplin Tornado Prevatt, D. O. et al. (2012). Joplin, Missouri, Tornado of May 22, 2011: Structural Damage Survey and Case for Lombardo, F. T., Roueche, D. B., and Prevatt, D. O. (2015). "Comparison of two methods of near‐surface wind speed estimation in the 22 May, Tornado‐resilient Building Codes, ASCE Publications. (http://ascelibrary.org/doi/book/10.1061/9780784412503) 2011 Joplin, Missouri Tornado." Journal of Wind Engineering and Industrial Aerodynamics, 138(0), 87‐97 Minor, J.E., McDonald, J.R., and Mehta, K.C. Tornado: an engineering‐oriented perspective. NOAA‐TM‐ERL‐NSSL‐82., Norman, OK (USA). National Severe Storms Lab., 1977. 8.
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