Assessment of Vulnerability to Hurricanes: November 1998

Natural hazards are sources of potential damage. Vulnerability results from the interaction of human activity with natural hazards. By virtue of sheltering the full range of human activity, the built-environment is at risk of sustaining damage when a given community is exposed to the impact of natural hazards. In Florida as a whole, but especially in the coastal regions, vulnerability to hurricanes is the greatest concern.

Vulnerability assessment is a method used to measure the degree of exposure of a building to specific hazards by characterizing possible impacts, and estimating potential damages, which also provides a foundation for risk assessment, and for identifying mitigation measures that can be implemented to reduce the potential for damage from recurring impacts.

While Vulnerability Assessment and impact characterization are readily available as tools for establishing criteria for the design of new buildings, the reality is that design professionals by and large limit themselves to just meeting the minimum requirements of the building code. The net result of this is that most existing buildings and residences in the coastal regions of Florida may only be capable of resisting the impact of a category 2 or moderate category 3 hurricane without major damage.

Such vulnerability is compounded for older buildings, which were designed and built before there was a building code or by using early standards that dis not take into account certain types of loads. Examples of this include buildings that were ‘engineered’ in the 1940s and well into the 1950s using ‘gravity loads’ and no lateral loads as the main external forces acting on their structures. As a result most of these buildings lack connections between structural members that can effectively resist extreme lateral loads, such as those generated by hurricanes, while otherwise being quite massive and strong.

It is important to note that these conditions do not equate to collapse or total structural failure of buildings under the impact of a major hurricane, but certainly create the probability for structural damage that could render such buildings unsafe after the impact of a major hurricane.

Against this background of limited design capabilities there are cases of building owners and managers of critical facilities who are concerned about ‘how safe’ these structures really are, especially in case of a hurricane. Will it be safe for patients and staff to remain sheltered in  a hospital located in the coastal zone? Is this facility capable of taking the hit of a hurricane without sustaining major damage? Will a given  facility be capable of continuing to function normally, or nearly so, in the aftermath of a hurricane? These are some of the questions being asked.

To answer these and other questions relative to how safe a building might be or, said differently, how capable it might be to resist the impact of a hurricane, or what needs to be done to make it hurricane-resistant or to enhance its capability to perform effectively under the impact of a major hurricane, building owners, facilities managers, and their design professionals, need to commission a dedicated study to assess the vulnerability of the building or facility that also includes recommendations for mitigation alternatives.

Ricardo A. Alvarez is an expert on Vulnerability Assessment and Hazard Mitigation, who has completed numerous such studies and participated in mitigation projects over the past twenty years, in addition to teaching graduate level university courses on both subjects for sixteen years, and conducting applied research on hurricane-resistant building design.

In 1998 Ricardo A. Alvarez integrated a professional team that completed a Vulnerability Assessment study for a major local hospital in Southeast Florida [For a summary description of the study please click of the following link CONSULTING25], to assist in consultations between the hospital and Miami-Dade County Emergency Management officials relative to hurricane evacuation criteria.

If you are a building owner of facilities manager interested in learning how vulnerable your facility is to hurricane impact, and what you can do to reduce the potential for damage from such impact, contact Ricardo A. Alvarez via email at or, or via telephone at [305]332-3664  or [305]931-0871 .

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