GAITHERSBURG,
Md.—Stricter
adherence to existing building standards, model building
codes and good building practices, and a greater recognition
of the risks posed by storm surge, could minimize the kind
of structural damage experienced in the Gulf Coast states
hit by Hurricanes Katrina and Rita last year, the Commerce
Department’s National Institute of Standards and Technology
(NIST) announced today.
A report
issued today by NIST documents the findings of a multi-organizational
team—coordinated by NIST and made up of experts from private-sector, academic
and federal entities—that deployed three subteams of technical experts
in October 2005 to areas impacted by Hurricanes Katrina and Rita to conduct a
broad-based reconnaissance on the performance of a variety of physical structures
during the storms.
The reconnaissance
was intended to identify new technical issues that need
to be addressed in the rebuilding effort, in the improvement
of building standards and model codes, and in future research
studies—and to build upon knowledge
gained from previous post-hurricane damage assessments.
The report makes
23 recommendations for specific improvements in the way
that buildings, physical infrastructure (such as bridges
and utilities) and residential structures are designed,
constructed, maintained and operated in hurricane-prone
regions across the United States—not just in the states
affected by Katrina and Rita.
Federal agencies,
state and local governments, and the private sector already
have taken many actions consistent with NIST’s
recommendations to facilitate rebuilding and mitigate the
potential for damage from future storms—in many cases
even as the findings were being analyzed and recommendations
were being formulated.
The NIST report
urges state and local agencies to adopt and enforce building
standards and model codes regarding hurricanes—and
to make relatively straightforward changes in building
practices. For example:
- Many roofing failures resulted from an inadequate
number of fasteners being used in installation or fasteners
being incorrectly located. NIST recommends that state
and localities consider licensing of roofing contractors,
continuing education of contractors and field inspection
programs to monitor roofs under construction.
- Wind-borne
gravel from building rooftops caused a great deal of
damage to nearby structures. Model building codes do
not permit this type of roofing in high-wind zones.
- Several
buildings were rendered inoperable because critical
equipment, such as electrical systems and backup
electrical generators, were located at or below grade
and damaged by floodwaters. Adoption and enforcement
of existing model code provisions that require a building’s
critical equipment to be placed above potential flood
levels could keep many buildings functioning following
a hurricane or return them to normal use more quickly.
- Masonry
wall failures observed during the reconnaissance may
have been prevented had the walls been properly anchored
and reinforced as required by model codes.
Several federal agencies already are acting on another area
of improvement identified in the report: reviewing and
updating flood hazard maps to better reflect the hazard
due to storm surge, current velocity and wave action in
the design of coastal structures—especially for the
affected Gulf Coast regions. Also being reviewed is the
Saffir-Simpson Hurricane Scale’s treatment of storm
surge effects. The scale provides an expected storm-surge
height associated with the intensity as determined by sustained
wind speed. In the case of Hurricanes Katrina and Rita,
the reconnaissance team found that storm surge heights
at several locations exceeded those associated with a wind-speed
based hurricane category. The National Oceanic and Atmospheric
Administration (NOAA) bases its hurricane advisories on
the results of detailed storm surge simulation models that
account for the local topography and bathymetry (depth
from the sea surface to the seafloor), as well as hurricane
parameters such as size and track.
The U.S. Army
Corps of Engineers (USACE) is taking a variety of major
steps to improve the flood protection system in New Orleans,
consistent with the NIST report’s recommendations
and beyond repairing damage to the New Orleans flood protection
system caused by Hurricane Katrina. The USACE Interagency
Performance Evaluation Task Force (IPET) is conducting a
detailed evaluation of the performance of the flood protection
system to provide credible scientific and engineering information
for guiding the immediate repair and future upgrade of the
system. A draft IPET report was released on June 1, 2006.
Additional recommendations in the NIST report cover the
performance during hurricanes of bridges and parking garages;
buildings (including pre-engineered metal buildings, moored
casino barges, portable classrooms and manufactured homes);
residential and building roofing systems; building envelopes
such as window systems and exterior cladding (to prevent
damage from wind, wind-borne debris and water-ingress); utility
(electric, water and gas) systems; and seaports (wharves
and large cargo cranes).
The NIST report’s
recommendations make clear what actions can be taken immediately
to lessen or prevent hurricane damage to structures, and
defines those actions that will require longer-term, greater
effort. NIST believes that all of its recommendations are
realistic, appropriate and achievable within a reasonable
period of time.
The NIST report, Performance of Physical Structures
in Hurricane Katrina and Hurricane Rita: A Reconnaissance
Report (NIST Technical Note 1476), is available online
at http://www.bfrl.nist.gov. NIST is working with the states
of Louisiana, Mississippi and Texas in conjunction with
FEMA to set up briefings on its report and recommendations
with state and local officials in June 2006. NIST also
intends to follow up with standards and codes organizations
on specific recommendations that impact them.
As a non-regulatory
agency of the U.S. Department of Commerce’s
Technology Administration, NIST promotes U.S. innovation
and industrial competitiveness by advancing measurement science,
standards and technology in ways that enhance economic security
and improve our quality of life.
BACKGROUND
The National Institute of Standards
and Technology (NIST)
Reconnaissance and Assessment of Damage
from Hurricanes Katrina and Rita
The
National Institute of Standards and Technology (NIST) reconnaissance
on the performance of physical structures following Hurricanes
Katrina and Rita complements other post-Katrina studies—completed and ongoing—by
the Federal Emergency Management Agency (FEMA), the Federal
Highway Administration (FHWA), the Multidisciplinary Center
for Earthquake Engineering Research (MCEER) with support
from the National Science Foundation (NSF), and the U.S.
Army Corps of Engineers (USACE). Although the agencies
have differing missions, there has been a great deal of
collaboration and open sharing of information among them.
NIST’s reconnaissance was the one federal study that
addressed damage from both hurricanes and the broad scope
of issues for major buildings, physical infrastructure (levees,
bridges, water and wastewater systems, power, communications
and industrial facilities) and residential structures. Additionally,
many of NIST’s recommendations are applicable to hurricane
prone regions of the country outside the areas directly affected
by the two hurricanes.
While
the findings from the reconnaissance and the recommendations
based on them are NIST’s, the report and recommendations
have been reviewed by the participating organizations.
NIST
began coordinating its efforts with other federal agencies
on Aug. 29, 2005, the day of Hurricane Katrina’s landfall
along the Louisiana-Mississippi border.
Four
staff from NIST deployed in cooperation with FEMA’s
Mitigation Assessment Team (MAT) to observe damage to buildings
and residential areas in coastal Mississippi during the week
of Sept. 26, 2005.
NIST
staff also coordinated visits to document breaches in the
levees and floodwalls with USACE staff. Two USACE staff
served on NIST reconnaissance teams in Louisiana and Mississippi.
One NIST staff member is currently participating on the
IPET study of the New Orleans flood protection system.
Two staff from the FHWA served on NIST reconnaissance teams
in Louisiana and Texas. In addition, NSF researchers affiliated
with MCEER participated in the NIST-led reconnaissance team.
The 16
organizations that participated in the NIST-coordinated damage
assessment team are NIST, the Applied Technology Council, USACE,
FHWA, the International Code Council, the National Council
of Structural Engineers Associations, the National Research
Council of Canada, Texas Tech University, the University at
Buffalo, the University of Puerto Rico, Amtech Roofing Consultants
Inc., Applied Residential Engineering Services, ImageCat Inc.,
Scawthorn Porter Associates Inc., Shiner Moseley and Associates
Inc., and Smith & Huston Inc.
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