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Design and Construction Guidance for Breakaway
Walls
Jeffrey Havelin,
P.E.
Overview
This
(one-hour) course is based on the FEMA construction guidelines for “breakaway”
walls used below Elevated Coastal Buildings.
In
Coastal High Hazard Areas (Zones V, VE, and V1-30), the National Flood Insurance
Program (NFIP) regulations require that communities participating in the program
adopt floodplain management ordinances or laws requiring that all new and
substantially improved buildings be elevated to or above the base flood
elevation (BFE) on foundations consisting of piles, posts, piers, or columns.
These
open foundations must be designed to allow waves and water moving at high
velocity to flow beneath the building. Local ordinances or laws adopted by
participating communities must further require that the area below the lowest
floor of the elevated building be left free of obstructions. Walls or other
obstructions below the elevated building can significantly increase the
potential for flood damage to the elevated building by increasing the surface
area subject to wave impact and velocity flow during a coastal storm.
Although obstructions are prohibited, the area below the lowest floor of an
elevated building in a Coastal High Hazard Area may be enclosed with open wood
latticework, insect screening, or non-supporting “breakaway” walls. However, each
of these must be designed and constructed to collapse under wind and water loads
without causing collapse, displacement, or other structural damage to the
elevated portion of the building or supporting foundation system. In addition,
like all other construction in the Special Flood Hazard Area, any enclosure
below the lowest floor of an elevated building must be built with
flood-resistant materials and with methods and practices that minimize flood
damage. Furthermore, the area below the lowest floor of the elevated building
may be used only for parking, building access, or storage.
The
student must take a multiple-choice quiz consisting of ten (10) questions at the end of this course
to earn PDH credits.
Specific Knowledge or Skill Attained
This course will specifically
review guidelines for breakaway walls used below Elevated Coastal Buildings,
and will cover the following topics:
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Breakaway wall, failure modes
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Breakaway wall, NFIP regulatory requirements
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Breakaway wall, requirement for construction with flood-resistant materials
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Breakaway wall, specifications for NFIP-compliant construction
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Breaking wave, impact on vertical surface
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Insect
screening for below-building enclosures
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Latticework for below-building enclosures
Course
Click on the following PDF
attachment and review Technical Bulletin (9-99) as published by the
FEDERAL EMERGENCY MANAGEMENT AGENCY,
publication number FIA-TB-9 prior to taking a quiz for credit. You will be quizzed on the
attached document
on its entirety.
Breakaway Walls Below Elevated Coastal Buildings (197 KB)
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Right click on the link. Select "Save Target As..."
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To obtain PDH credits for this course, you will need to take a quiz for
credit. Click on the link below.
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