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, according to NIST.
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.
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. Another objective is for NIST to work 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, officials have said.
