Improved FUJITA SCALE EF Scale 11A preparation exhibited to NATIONAL WEATHER SERVICE Silver Spring, Maryland June 28, 2.


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ENHANCED FUJITA SCALE (EF Scale) 1 1 A briefing presented to NATIONAL WEATHER SERVICE Silver Spring, Maryland June 28, 2004 Wind Science and Engineering Center Texas Tech University. Theodore T. Fujita. Limitations of Fujita Scale. Difficult to apply consistently
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Slide 1

Improved FUJITA SCALE (EF Scale) 1 A preparation displayed to NATIONAL WEATHER SERVICE Silver Spring, Maryland June 28, 2004 Wind Science and Engineering Center Texas Tech University

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Theodore T. Fujita

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Limitations of Fujita Scale Difficult to apply reliably insufficient harm pointers Does not represent development quality No conclusive relationship amongst\'s harm and wind speed

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Fujita Scale Enhancement Project WISE consented to start venture Funding was accessible through NIST Co-PI\'s each have over 30 years involvement with tornado harm

Slide 5

Co-PI\'s James R. McDonald, Ph.D., PE. Tornado harm documentation experience Tornado risk appraisal Tornado harm relief Kishor C. Mehta, Ph.D., P.E. Executive of WISE (Retired) Chair ASCE 7 Wind Load Task Committee Internationally perceived analyst

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WISE Strategy Choose a directing Committee Involve numerous clients Develop an arrangement Obtain an accord

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Steering Committee

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Steering Committee Objectives Organize a gathering of clients Identify key issues Recommend another or changed Fujita Scale Develop techniques to acquire an agreement

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Fujita Scale Forum March 7-8, 2001 Grapevine, Texas 20 of 26 welcomed members went to Developed systems for an upgraded Fujita Scale

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Strategies Define extra harm pointers Correlate appearance of harm with wind speed Preserve verifiable tornado information base Obtain contribution from clients

Slide 11

Damage Indicators (DI\'s) WISE group proposed 28 DI\'s Buildings, structures and trees DI\'s portrayed in subtle element Additional DI\'s can be included future

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Degrees of Damage (DOD\'s) Each DI has a few degrees of harm DOD\'s reach from no harm to aggregate demolition DOD\'s are masterminded all together of expanding harm They are a component of wind pace

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Correlation of Damage and Wind Speed Need expected, upper and lower headed wind speeds for every DOD Expected wind speed in light of "ordinary" conditions Upper and lower bound wind speeds speak to conceivable deviation from the "typical" circumstance

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Approach Deterministic Monte Carlo Expert elicitation

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Expert Elicitation Used effectively to estimate seismic physical parameters Senior Seismic Hazard Assessment Committee (SSHAC – 1997) Experts make best gauges of expected, upper and lower bound wind speeds Follow an all around characterized convention The final product is the most ideal evaluation of the fancied parameter

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SSHAC Elicitation Process Describe DI\'s and DOD\'s Identify and draw in a board of specialists Discuss issues with specialists; give information Train specialists in elicitation process Conduct singular elicitations and gathering collaborations

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SSHAC Elicitation Process Analyze and total elicitations and intention issues Refine wind speed gauges with a few cycles Document and impart procedure and last results Obtain extra companion survey of procedure and results

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Elicitation Experts

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Elicitation Procedure Wind rates are 3-second blasts at 10 m in level open landscape Experts met for one and one-half days Conducted 3 rounds of elicitation

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Results of Elicitation Name and depiction of DI DOD\'s and assessed wind speeds Order DOD\'s by expanding wind speeds Plot DOD\'s versus wind speed Provide photograph cases of DOD\'s

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One-and Two-Family Residences (FR12) Typical Construction : Asphalt shingles, tile, slate or metal rooftop covering Flat, peak, hip, mansard or mono-inclined rooftop or mix thereof Plywood/OSB or wood board rooftop deck Prefabricated wood trusses or wood joists and beam development Brick polish, wood boards, stucco, EIFS, vinyl or metal siding Wood or metal stud dividers, solid pieces or protecting solid boards Attached single or twofold carport

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One-and Two-Family Residences (FR12)

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One-and Two-Family Residences (FR12)

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One-and Two-Family Residences (FR12) FR12: DOD4: Uplift of rooftop deck and loss of rooftop covering ( >20%); carport entryway falls outward

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One-and Two-Family Residences (FR12) FR12: DOD6: Large areas of rooftop evacuated; most dividers stay standing

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One-and Two-Family Residences (FR12) FR12: DOD7: Top floor (First floor for this situation) outside dividers fallen

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One-and Two-Family Residences (FR12) FR12: DOD10: Total decimation of whole building

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Correlation of Fujita Scale and EF Scale Used a second gathering of specialists They allocated Fujita Scale classifications to every DOD Ratings were changed over to 3-second blast middle wind speeds Obtained normal of Fujita Scale wind speeds

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Correlation of Fujita Scale and EF Scale Performed a relapse examination to get connection between\'s normal Fujita Scale and expected EF Scale wind speeds Regression condition:

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Correlation of Fujita Scale and EF Scale Wind Speeds

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Derived EF Scale Wind Speed Ranges

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Recommended EF Scale Wind Speed Ranges

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EF5 Wind Speed Range We suggest no upper bound on this class Physical upper bound tornado wind speed not known Will evade people accepting most dire outcome imaginable for EF5 class

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Rating an Individual Building Find DI that matches the building sort and development Observe the harm and match to one of the DOD\'s Determine if wind velocity to bring about watched harm is higher, lower or equivalent to the normal worth inside the wind speed range

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Rating an Individual Building The alloted EF Scale rating is the one whose scope of wind pace contains the assessed wind pace to bring about the DOD. Extra DI\'s ought to be considered in allocating and EF Scale to a tornado occasion

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Rating a Tornado Event Conduct a flying overview to distinguish potential DI\'s and to characterize degree of harm way Identify 2 or more DI\'s that appear to show the most elevated wind speed in the way Locate these DI\'s inside the harm way Follow ventures for individual structures or structures and report comes about

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Rating a Tornado Event Considering a few DI\'s, assessment greatest tornado wind speed Assign EF Scale class in view of the greatest evaluated wind speed Record premise for EF Scale rating Record other correlated information identifying with the tornado occasion

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Presentations and Workshops Fujita Symposium, January 2000 National Severe Storms Workshop, March 2001 U.S. National Conference on Wind Engineering, June 2001 AMS National Conference, January 2002 21 st Conference on Severe Local Storms, August 2002 11 th International Conference on Wind Engineering, June 2003 22 nd Conference on Sever Local Storms, October 2004 (Paper acknowledged)

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WISE Website www.wind.ttu.edu

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Conclusion We have taken after the procedures of guiding board of trustees and discussion Provided extra harm markers Established relationship amongst\'s harm and wind speed Determined connection amongst\'s Fujita and EF Scales Presented our work in various settings

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