HURRICANE ANDREW

1
HURRICANE ANDREW

• August 24, 1992
• 25 billion damage to both residential and
  commercial structures
• Max sustained wind speed was 145 mph (Category IV)

2
(No Transcript)
3
(No Transcript)
4
ASSESMENT OF DAMAGE

• Lifeline Facilities - (power plant, hospitals,
  communication centers) Very little damage
• Above-Ground Utility Systems - (electric and
  telephone lines) extended outages to area
  residents due to failure of electric transmission
  lines

5
Assessment of Damage

• Under-Ground Utility Systems Very little damage.
  A few cases of water and gas broken lines due to
  uprooted vegetation
• Transportation Systems Loss of traffic signals
  and signs

6
Recommendations

• Install underground services to critical lifeline
  facilities
• Provide adequately sized emergency generators at
  critical facilities
• Design traffic and sign supports to resist
  hurricane force winds
• Install underground electrical feeds to signal
  systems on major arteries

7
Multi-Story Structures

• Very little damage to major structural components
• Substantial economic damage due to loss of
  cladding and roofing materials (interior damage
  due to wind and water penetration)

8
Recommendations

• Adequately design or load test cladding and its
  connections for wind loads
• Develop standardized test methods for all roofing
  materials

9
Low-Rise Commercial Structures

• The loss of roofing, doors, windows, and cladding
  resulted in wind and water penetration

10
Recommendations

• Develop and implement Building code requirements
  for design and testing of roofing, doors, and
  windows
• Design roof members for uplift force in
  accordance to ASCE 7 standards

11
Conventional Residential Structures

• Performed poorly due to failure of roofing
  materials, doors, and windows
• Loss of roofing materials allow weather
  penetration of the affected building and
  contributed to the wind blown debris that lead to
  damage of other buildings
• The loss of roof sheathing was mainly caused by
  inadequate nailing

12
Residential Structures Continued

• A large portion of the sheathing failure occurred
  along the eaves or near the ridge of gable roof
  buildings
• In some cases, wall failure occurred due to the
  use of hardboard siding, without plywood backing
  on the exterior walls

13
Summary of Damages Experienced by Homes in Florida
14
Recommendations

• Use of partial mortar beds for tile roofs and
  staples for shingles is totally inadequate
• Doors should be capable of withstanding the
  design wind load and should be rated according to
  wind resistance
• Protection devices should be required for all
  windows and glass doors or they should be tested
  for resistance to missile impact

15
Recommendations Continued

• Sheathing inspection should be performed prior to
  covering the roof deck
• Prescriptive details for attaching gable-end
  walls should be adopted and enforced
• Design reviews and inspections should ensure
  adequate connections between all individual
  elements in the lateral load path

16
(No Transcript)
17
(No Transcript)
18
Manufactured Structures

• Nearly 100 of the manufactured housing was
  destroyed
• Manufactured school facilities survived

19
Recommendations

• Design the manufactured structures to the same
  wind loads as the others
• Use long, heavy-duty steel, screw-type tie-downs
  spaced every 4 feet
• If the mobile home site is to be permanent, a
  concrete foundation is preferred