Presentation on theme: "1 Demonstration of Methodology Expert Panel Open Meeting Austin, Texas November 12, 2014."— Presentation transcript:
1 Demonstration of Methodology Expert Panel Open Meeting Austin, Texas November 12, 2014
2 Agenda Introductions Overview Preliminary Overall Methodology Demonstration of Methodology Site Residential Features Hazard Module Damage Module Results Future Work Q&A
3 Introductions Sam Amoroso, Ph.D. P.E., S.E.Forte & Tablada, Inc. Bob Bailey, Ph.D., P.E.Exponent, Inc. Bill Coulbourne, P.E.Coulbourne Consulting Andrew Kennedy, Ph.D. University of Notre Dame Doug Smith, Ph.D., P.E.Texas Tech University
4 Overview 1 st Open Meeting: Austin, August 22, 2013 2 nd Open Meeting: Corpus Christi, December 10, 2013 3 rd Open Meeting: Austin, March 13, 2014 4 th Open Meeting: Austin, May 29, 2014 5 th Open Meeting: Austin, August 7, 2014 6 th Open Meeting: Austin, November 12, 2014
5 1 st Open Meeting Panel Member Backgrounds The TWIA expert panel has been appointed under Insurance Code § and 28 Texas Administrative Code §§ The panel’s purpose is to develop ways of determining whether a loss to TWIA-insured property was caused by wind, waves, tidal surges, or rising waters not caused by waves or surges. After the panel completes its work, the commissioner will consider the panel’s findings and publish guidelines that TWIA must use to settle claims.
6 2 nd Open Meeting Present Preliminary Overall Methodology Initial Focus: Residential Slab Only Claims
7 3 rd Open Meeting Present Proposed Hazard Module Methodology Goal: To provide a time history of wind, surge, and wave heights for a given property location.
8 4 th Open Meeting Present Proposed Damage Module Methodology Goal: To provide an estimate of component damage attributable to wind prior to collapse of the structure due to surge forces.
9 5 th Open Meeting Present Proposed Economic Loss Methodology Goal: To provide an estimate of the loss due to component damage attributable to wind prior to collapse of the structure due to surge forces.
10 TDI Website
11 Preliminary Overall Methodology
12 Demonstration of Methodology: Site Surviving Structure Slab-only Structure
13 Pictometry™: Aerial View Before Ike
14 Pictometry™: Aerial View After Ike
15 Residential Features Roof shape: Gable Roof cover type: Asphalt Shingle Roof slope: 4:12 Roof height: 20 ft. Roof cover age: 9 years Length: 42 ft. Width: 34 ft. Eave height: 17 ft.
16 Residential Features Structure primary axis: 60° Terrain exposure: D Overhead garage door: Yes Direction of garage door: 240° Garage panel door width: Single Garage attached: Yes Percent window area: 0-25 Elevation of Lowest Horizontal Structural Member: ft.
17 Hazard Module: Objectives Goals Site Specific: Wind speed time history Wind direction time history Surge time history Wave time history Minimum of error Used to predict damage to individual structure as the storm passes
18 Hazard Timing 12 m/s 75 deg 10 ft 2.2 ft
19 Hazards Module Flow Chart Steps Collect Hurricane Wind Field Data over Life of Storm. Develop Global Hurricane Wind Field. Use the hurricane wind field as input to surge model and wave model. Obtain time correlated histories. Refine the time histories. Final time histories for vulnerability module.
20 Wind Speeds: Hurricane Ike at Landfall
21 Hazard Module: Wind Field Exemplar
22 Hazard Module: Surge + Wave Definitions Separate inundation into waves and surge Surge is the slow variation of average water levels over periods of 10 minutes or longer Waves are the faster variation of water levels Like waves at the beach Typically 5-20s periods dominate in hurricanes At a given location wave and surge properties will define the hazard. When combined with the structural properties, these will allow damage estimates.
23 Example of High Resolution Hurricane Ike Simulation using SWAN+ADCIRC SWAN computes waves, ARCIRC computes surge May not be the only model choice that could give good results. 18 million element simulation using hindcast winds (high accuracy reconstruction). Resolution down to 20m in some complex areas. Runs on parallel computer (like all high resolution simulations). Tides included. Comparisons against high water marks, NOAA gauges, rapidly installed gauges.
26 Surge + Wave Fragility Probability of slabbing defined for houses exposed to waves and surge. Inputs: Significant Wave Height Surge Elevation Lowest Horizontal Structural Member House Age Based on almost 2000 homes examined after Ike. Once Probability of slabbing exceeds a threshold, house has failed; no more wind damage is possible.
27 Inputs for Surge + Wave Vulnerability Significant Wave Height Surge Elevation House Age (in ranges of years) Lowest Horizontal Structural Member Elevation
28 Damage Module Input Hazard Time Histories Wind Surge + Wave Construction Features Output Time of probable collapse from surge + waves Time Histories of component damage due to wind
29 Damage Module Construction Features: Surviving Structure Slab-Only Structure
30 Damage Module Surviving Structure: Time of Probable Collapse ft.
31 Damage Module Slab-Only Structure: Time of Probable Collapse ft.
32 Damage Module Surviving Structure: Component Damage Time Histories
33 Damage Module Slab-Only Structure: Component Damage Time Histories Point where structure topples over.
38 Results Slab-Only Structure: Roof Cover Damage Variation with Height and Exposure
39 Future Work Peer Review Finalize recommendations and present to TDI Continue with Model Development: Consideration of model building code changes. Impact of WPI information on building vulnerability. Consideration of the use of TDI-tested building products. A method or model to estimate damage to commercial properties starting with slab-only cases.