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Demonstration of Methodology

Expert Panel Open Meeting

Austin, TexasNovember 12, 2014

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Agenda

Introductions Overview Preliminary Overall Methodology Demonstration of Methodology

Site Residential Features Hazard Module Damage Module Results

Future Work Q&A

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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

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Overview

1st Open Meeting: Austin, August 22, 2013

2nd Open Meeting: Corpus Christi, December 10, 2013

3rd Open Meeting: Austin, March 13, 2014

4th Open Meeting: Austin, May 29, 2014

5th Open Meeting: Austin, August 7, 2014

6th Open Meeting: Austin, November 12, 2014

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1st Open Meeting

Panel Member Backgrounds

The TWIA expert panel has been appointed under Insurance Code §2210.578 and 28 Texas Administrative Code §§5.4260-5.4268. 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.

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2nd Open Meeting

Present Preliminary Overall Methodology Initial Focus: Residential Slab Only Claims

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3rd Open Meeting

Present Proposed Hazard Module Methodology Goal: To provide a time history of wind, surge, and

wave heights for a given property location.

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4th 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.

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5th 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.

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TDI Website

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Preliminary Overall Methodology

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Demonstration of Methodology: Site

Surviving Structure

Slab-only Structure

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Pictometry™: Aerial View Before Ike

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Pictometry™: Aerial View After Ike

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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.

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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 StructuralMember: 14.83 ft.

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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

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Hazard Timing

12 m/s

75 deg

10 ft 2.2 ft

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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.

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Wind Speeds: Hurricane Ike at Landfall

A

C

B

D

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Hazard Module: Wind Field Exemplar

9AM 2PM 7PM 12AM 4AM 9AM 2PM 7PM 12AM30

40

50

60

70

80

90

100

110G

ust

Win

d S

pe

ed

(V

) [m

ph

]

Time (UTC) Beginning 09-Sept-2008 13:30:00

Wind Speed and Direction

9AM 2PM 7PM 12AM 4AM 9AM 2PM 7PM 12AM0

50

100

150

200

250

300

Win

d D

ire

ctio

n (Q

) [°

]

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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.

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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.

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Surge + Wave: Hurricane Ike

Source: ARCADIS U.S., Inc., Highlands Ranch, Colorado 80129

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Hazard Module: Surge + Wave Exemplar

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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.

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Inputs for Surge + Wave Vulnerability

Significant Wave Height

Surge Elevation

House Age(in ranges of years)Lowest

Horizontal Structural Member Elevation

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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

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Damage Module

Construction Features:

Surviving Structure Slab-Only Structure

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Damage Module

Surviving Structure: Time of Probable Collapse

18.24 ft.

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Damage Module

Slab-Only Structure: Time of Probable Collapse

14.83 ft.

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Damage Module

Surviving Structure: Component Damage Time Histories

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Damage Module

Slab-Only Structure: Component Damage Time HistoriesPoint where structure

topples over.

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Damage Module

Gable Roof Zones:

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Damage Module

Wall Zones:

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Results

Surviving Structure: Component Wind DamageTime Roof Cover Roof Panel Wall Cover Wall Panel Windows Doors Garage Dr Roof Frame Interior

9/12/08 13:30 0.9% 0.8% 0.9% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%9/12/08 14:00 0.9% 0.8% 0.9% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%9/12/08 14:30 1.0% 0.8% 0.9% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%9/12/08 15:00 1.0% 0.8% 1.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%9/12/08 15:30 1.0% 0.8% 1.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%9/12/08 16:00 1.0% 0.8% 1.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

9/13/08 5:00 2.1% 1.1% 2.4% 0.0% 0.3% 0.1% 0.0% 0.0% 0.1%9/13/08 5:30 2.3% 1.2% 2.6% 0.0% 0.4% 0.2% 0.0% 0.0% 0.1%9/13/08 6:00 2.7% 1.3% 2.8% 0.0% 0.5% 0.3% 0.0% 0.0% 0.1%9/13/08 6:30 2.9% 1.3% 2.9% 0.0% 0.6% 0.4% 0.0% 0.0% 0.2%9/13/08 7:00 3.2% 1.4% 3.2% 0.0% 0.8% 0.5% 0.0% 0.0% 0.2%9/13/08 7:30 3.3% 1.4% 4.5% 0.0% 1.4% 1.0% 0.0% 0.0% 0.3%9/13/08 8:00 4.2% 1.6% 5.1% 0.0% 2.0% 1.5% 0.1% 0.0% 0.4%9/13/08 8:30 5.6% 1.9% 6.4% 0.0% 3.3% 2.9% 0.2% 0.0% 0.8%9/13/08 9:00 6.1% 2.0% 8.3% 0.0% 5.6% 5.4% 0.4% 0.0% 1.2%9/13/08 9:30 9.0% 2.5% 9.3% 0.1% 7.0% 7.0% 0.8% 0.0% 2.4%

9/13/08 10:00 10.0% 2.7% 12.4% 0.2% 10.7% 11.6% 1.5% 0.0% 3.4%9/13/08 10:30 16.4% 4.2% 18.1% 0.8% 21.1% 23.0% 9.2% 0.1% 8.6%9/13/08 11:00 16.4% 4.2% 18.1% 0.8% 21.1% 23.0% 9.2% 0.1% 8.6%

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Results

Slab-Only Structure : Component Wind DamageTime Roof Cover Roof Panel Wall Cover Wall Panel Windows Doors Garage Dr Roof Frame Interior

9/12/08 13:30 0.9% 0.7% 0.9% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%9/12/08 14:00 0.9% 0.7% 0.9% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%9/12/08 14:30 1.0% 0.8% 1.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%9/12/08 15:00 1.0% 0.8% 1.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%9/12/08 15:30 1.0% 0.8% 1.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%9/12/08 16:00 1.0% 0.8% 1.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%9/12/08 16:30 1.0% 0.8% 1.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%9/12/08 17:00 1.1% 0.8% 1.1% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%9/12/08 17:30 1.1% 0.8% 1.1% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%9/12/08 18:00 1.1% 0.8% 1.2% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%9/12/08 18:30 1.2% 0.8% 1.2% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

9/13/08 4:00 2.6% 1.2% 2.3% 0.0% 0.2% 0.1% 0.0% 0.0% 0.1%9/13/08 4:30 2.6% 1.2% 2.3% 0.0% 0.2% 0.1% 0.0% 0.0% 0.1%9/13/08 5:00 2.6% 1.2% 2.4% 0.0% 0.3% 0.1% 0.0% 0.0% 0.1%9/13/08 5:30 2.8% 1.2% 2.7% 0.0% 0.4% 0.2% 0.0% 0.0% 0.1%9/13/08 6:00 2.9% 1.2% 2.9% 0.0% 0.5% 0.3% 0.0% 0.0% 0.1%9/13/08 6:30 3.9% 1.4% 3.1% 0.0% 0.7% 0.4% 0.0% 0.0% 0.2%9/13/08 7:00 4.2% 1.5% 3.3% 0.0% 0.8% 0.6% 0.0% 0.0% 0.2%9/13/08 7:30 4.6% 1.5% 3.5% 0.0% 1.1% 0.7% 0.0% 0.0% 0.3%9/13/08 8:00 4.9% 1.6% 4.7% 0.0% 2.3% 1.8% 0.1% 0.0% 0.5%9/13/08 8:30 7.1% 1.9% 5.4% 0.0% 3.2% 2.7% 0.1% 0.0% 1.0%9/13/08 9:00 8.0% 2.1% 8.3% 0.0% 5.6% 5.4% 0.4% 0.0% 1.5%

9/13/08 13:00 20.6% 4.2% 18.2% 0.8% 21.0% 23.1% 14.1% 0.0% 12.0%9/13/08 13:30 20.6% 4.2% 18.2% 0.8% 21.0% 23.1% 14.1% 0.0% 12.0%9/13/08 14:00 20.6% 4.2% 18.2% 0.8% 21.0% 23.1% 14.1% 0.0% 12.0%9/13/08 14:30 20.6% 4.2% 18.2% 0.8% 21.0% 23.1% 14.1% 0.0% 12.0%9/13/08 15:00 20.6% 4.2% 18.2% 0.8% 21.0% 23.1% 14.1% 0.0% 12.0%9/13/08 15:30 20.6% 4.2% 18.2% 0.8% 21.0% 23.1% 14.1% 0.0% 12.0%9/13/08 16:00 20.6% 4.2% 18.2% 0.8% 21.0% 23.1% 14.1% 0.0% 12.0%9/13/08 16:30 20.6% 4.2% 18.2% 0.8% 21.0% 23.1% 14.1% 0.0% 12.0%

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Results

Slab-Only Structure: Roof Cover Damage Variation with Height and Exposure

15 ft 20 ft 25 ft2.3% 2.3% 2.3%7.7% 7.7% 7.7%2.7% 2.8% 3.1%9.5% 10.0% 11.2%3.6% 3.8% 4.1%18.7% 19.6% 21.4%

Mean Roof Height

B

C

D

Exposure

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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.

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Q&A