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Wind vs. Water Presented by: Michael D. Spensieri, P.E. Regional Engineering Manager Office: 800-482-5611, Ext: 2018 www.donan.com

Michael D. Spensieri, P.E. B.S.C.E. from West Virginia University Presenter Licensed P.E. in 12 states in the Eastern U.S. 16+ years of experience in the construction and forensic engineering fields Managed DONAN s CAT response to Storm Sandy DONAN has completed over 1,000 Storm Sandy projects to date

Goals Open environment Interactive discussion PLEASE ask questions TCB as needed while respecting others Let s learn about wind, water, their forces and how each affect structures!

FEMA investigation tips Researching the event Weather and storm data Site study guidance Wind forces and results Water forces and results Wave formation Hydrostatic forces with Case Study No. 1 Hydrodynamic forces with Case Study No. 2 Buoyant forces with Case Study No. 3 Frictional forces with Case Study No. 4 Settlement or Subsidence Outline

Wind / Water Investigation Tips FEMA-provided site investigation tips: http://nfipiservice.com/pdf/bulletin/w-08008.pdf Hurricanes and other severe storms may result in damage caused by both wind and flood. When handling these claims, adjusters should use proven investigative methods such as those provided in the attached document, which was adapted from the 1998 NFIP pamphlet, Wind/Water Investigative Tips.

Wind / Water Investigation Tips Weather data: Research local newspapers Check weather services to find specific storm data When damage is caused by a hurricane, determine and record the following (including timing and duration): Highest wind speed Barometric pressure Amount of rainfall Tidal heights Storm surge Wave heights

Wind / Water Investigation Tips Weather Data Services: National Weather Service (NWS) www.weather.gov United States Geological Survey (USGS) http://water.usgs.gov/floods/ National Hurricane Center (NHC) http://www.nhc.noaa.gov/ FEMA meteorologist by telephone (202) 566-1600, extension 3071

Wind / Water Investigation Tips NWS Website Storm Sandy Information

Wind / Water Investigation Tips USGS Website Storm Sandy Information jjjj

Wind / Water Investigation Tips Weather data with respect to loss location: Record the distance to loss location Record the direction to the loss location from the center of the storm FYI, wave and surge heights are higher to the northeast of the storm s path/eye

Wind / Water Investigation Tips Research and record site conditions: Original ground elevation Distance from body of water After-storm ground elevation or other indications of soil displacement of scour Amount and type of storm debris

Wind / Water Investigation Tips Canvasing: Be certain to identify where each witness was at the time of the storm, the amounts or descriptions of wind and flood each witness saw, and the time of day that each made their respective observations Record in the claim/project files only what each witness actually says they observed not hearsay or your opinion

Wind / Water Investigation Tips Site Study: Check for and photograph the debris field Measure and record how many feet the debris field is from the shoreline and describe the topography in detail Note presence or absence of collateral damage (e.g., fences, sheds, neighboring houses, etc.) Determine and record a complete description of the damaged or demolished buildings, including construction type Photograph (close-up) the remains of connectors or tie-downs

Wind / Water Investigation Tips

Site Visit: Wind / Water Investigation Tips Photograph houses and objects adjacent to the loss location

Wind / Water Investigation Tips Site Study: Note where evidence suggests the insured risk was not built as securely as neighboring buildings Check for and photograph any wind-caused openings in structures and/or missing roof coverings/shingles

Wind / Water Investigation Tips

Site Visit: Wind / Water Investigation Tips Photograph interior and exterior high water marks

Wind / Water Investigation Tips Site Study: Check for and photograph visible water marks or debris in nearby trees or on fence posts

Wind / Water Investigation Tips Site Study: Check for and photograph uprooted trees or trees snapped off at a high level

Wind / Water Investigation Tips Site Study: Check for, photograph, and note evidence of erosion or scour

Wind vs. Water

And in this corner

Pre-fight intro Caused by a difference in air pressures From a storm front near you Weighing in at nothing The challenger

Wind Forces & Results Wind generates two components acting on structures: Pressure against the building Impact from wind-borne debris Wind damage: Wind pressure increases with increasing height Damage is greatest from top to the bottom Damage is greatest from the outside to the inside Before structural damage occurs, damage is expected to weaker, non-structural components such as??? The foundation is typically the last place damaged

Wind Forces & Results Source: hurricanescience.org

Wind Forces & Results

And now in this corner

Pre-fight intro Like glass when still, but a freight train when in motion Found at a beach or river bed near you Weighing in at 62.4 pounds per cubic foot The reigning champion

Water Forces

Water Forces & Results Water-generated components acting on structures: Hydrostatic forces Hydrodynamic forces (e.g., moving water, breaking waves, debris impact) Buoyant forces Frictional forces Settlement Water damage: Direct damage is concentrated at or below the water line Foundation damage is common Roof coverings and framing are often left intact

Hydrostatic Forces Hydrostatic forces can be described as the force that water applies to the back side of a dam wall, like those that contributed to the Teton Dam to collapse in 1976. Source: wikipedia.org

Hydrostatic Forces Hydrostatic pressure is dependent on depth and the greater the depth, the greater the pressure. Six feet of water depth = 187 psf Source: southholland.org

Case Study No. 1 - Hydrostatic Claim: Basement wall collapse during Storm Sandy Location: Sayreville, NJ

Loss Location Case Study No. 1 - Hydrostatic

Rear (north) basement wall collapsed inward Case Study No. 1 - Hydrostatic

Case Study No. 1 - Hydrostatic Subject loss facts/observations: 1½-story house over a basement with unreinforced CMU block walls High-water depth/marks at 5.2 feet above ground No scour, no displaced siding, no moving water evidence North basement wall collapsed. Horizontal cracks in the south, east and west basement walls South, east and west walls lean inward above the horizontal cracks

Case Study No. 1 - Hydrostatic Claim: Basement wall collapse during Storm Sandy Location: Sayreville, NJ O/C & Conclusions: The basement wall failed due to the hydrostatic pressure behind the wall and horizontal earth pressure The wall failure occurred due to the lack of water in the basement when the exterior hydrostatic pressure built up

Wind Wave Creation Creating wind waves takes three things: 1. High winds Winds in excess of 20 mph can generate moving water and substantial waves 2. Fetch distance Downwind distance over open water that is greater than or equal to 1,500 feet 3. Time Wind speed and fetch distance play a role, but it generally takes 1 to 2 hours of consistent wind over a fetch to generate moving water and waves

Wind wave creation facts: Wind Wave Creation The energy to the sea increases to the 4 th power of the wind speed Maximum size is reached when wave travels almost as fast as the wind A 60 knot storm lasting 10 hours makes a 45-ft wave Source: seasfriends.org

Breaking Waves Source: CK-12.org

Types of Waves Tidal waves: Relatively harmless waves associated with the tides. Tsunami and storm surges are sometimes incorrectly referred to as "tidal waves" in popular writing. Storm surge: Abrupt bulge of water driven ashore by a tropical cyclone (i.e., Hurricane) Tsunami: Long-wavelength, shallow-water progressive waves caused by the rapid displacement of ocean water. Caused by??? Seismic sea wave: Tsunami caused by the sudden, vertical movement of Earth along faults NOTE All seismic sea waves are tsunamis, but not all tsunamis are seismic sea waves

Hydrodynamic Forces Hydrodynamic forces are imposed on a structure by water flowing against and around it

Hydrodynamic Forces

Case Study No. 2 - Hydrodynamic Claim: Walls failed during Storm Sandy Location: Mystic Island, NJ

Case Study No. 2 - Hydrodynamic Loss Location Atlantic City, NJ

Case Study No. 2 - Hydrodynamic Termite damage to framing. Nails up to 7 feet apart!!! Repaired wall with nailing every 16 inches. Recent addition

Case Study No. 2 - Hydrodynamic Wall displaced outward Minimal cracking in the 2 nd -story walls Garage door location. Likely unreinforced for 1960s construction.

Case Study No. 2 - Hydrodynamic Wall displaced outward Wall displaced inward

Case Study No. 2 - Hydrodynamic No movement in 2 nd floor Base of wall displaced outward Unanchored deck posts displaced

Case Study No. 2 - Hydrodynamic Subject loss facts/observations: Two-story house on a slab-on-grade foundation Front of house faces southeast toward open water Open water fetch distance is ~4 miles Interior high water mark/depth at 5.0 feet Obvious damage and debris fields No scour, but some soil displacement

Case Study No. 2 - Hydrodynamic Claim: Walls failed during Storm Sandy Location: Mystic Island, NJ O/C & Conclusions: Damage and displacement caused by moving water, specifically hydrodynamic forces. Condition (e.g., termite damage) and inadequately constructed sections of the home (e.g., unanchored posts, inadequate nailing) contributed to the amount of damage/loss.

Debris Impact Debris Impact damage is typically limited to the point of impact and damage is similar to a vehicle hitting a house

Case Study No. 3 - Debris Impact Claim: Exterior house damage during Storm Sandy Location: Mantoloking, NJ LOSS LOCATION House destroyed from velocity flow and wave action Sand on roof!

Case Study No. 3 - Debris Impact

Case Study No. 3 - Debris Impact No cracked or displaced floor framing No cracks in slab

Case Study No. 3 - Debris Impact Claim: Exterior house damage during Storm Sandy Location: Mantoloking, NJ O/C & Conclusions: Damage and displacement caused by debris impact No movement or damage directly caused by hydrodynamic forces is evident inside or under house

How does the boat float???

Objects float when their weight equals the weight of the water displaced by the object. Buoyancy pressure does not increase with water depth. Buoyancy Force

Buoyancy Force Source: akitarescueoftulsa. com

Buoyancy Force or House Boat?

Erosion and Scour Soil erosion is the wearing away of soil by water, wind or ice. Scour occurs when moving water accelerates around an obstruction in the water column. Scour is localized.

Case Study No. 4 - Scour Claim: House displaced during Storm Sandy Location: Lavallette, NJ LOSS LOCATION

Case Study No. 4 - Scour Concrete Slab Void

Case Study No. 4 - Scour Slab is separated from wall framing

Case Study No. 4 - Scour Claim: House displaced during Storm Sandy Location: Lavallette, NJ O/C & Conclusions: Moving water resulted in frictional forces displacing foundation supporting soils Scour around and below the structure caused failures of the wall and floor systems

Moisture in Soil: Settlement The key to loading earth with a foundation is to control the moisture in the soil Well-compacted and maintained soil has two physical properties that allow it to hold together: cohesion and shear resistance Cohesion is the attractive nature of the particles and moisture in soil can neutralize this attraction Shear resistance has to do with the shape of individual soil particles and how they rub against one another to lock into place As the soil moisture increases, the soil s ability to carry weight decreases

Settlement Source: ashireporter.org

Wind vs. Water Differences

Wind vs. Water Differences Tale of the tape Pressure from 150-mph wind = 60 psf Pressure from moving water at 10 mph = 210 psf Pressure from 20-foot breaking wave = 600 psf Don t under estimate uplift wave pressures!

And the winner is Water and wave action!!!

Coming soon to a theater near you

Sharkicane!!!

Questions???

Thank you!!! Michael D. Spensieri, P.E. Regional Engineering Manager Office: 800-482-5611 Ext: 2018 Mobile: 704-477-7125 www.donan.com

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