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.

24 Surge + Wave: Hurricane Ike Source: ARCADIS U.S., Inc., Highlands Ranch, Colorado 80129

25 Hazard Module: Surge + Wave Exemplar

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.

34 Damage Module Gable Roof Zones:

35 Damage Module Wall Zones:

36 Results Surviving Structure: Component Wind Damage

37 Results Slab-Only Structure : Component Wind Damage

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.

40 Q&A