Multi-Hazard Mitigation Plan: Executive Summary

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Executive Summafv Changes to Risk Exposure Due to Successful Mitigation Projects • Critical Facility Study. An all-hazard screening of critical facility buildings in the County of Hawaii has been conducted and a HAZUS MH risk assessment model created to evaluate the expected losses for each building. Two facility groups, that ranked high based on these analyses were evaluated in more detail such that recommended mitigation procedures were developed. A Benefit-Cost Analysis of the mitigation project construction funding was performed. This detailed evaluation provided the information necessary to submit a PDM grant applications for the retrofit project, and prioritize the most vulnerable critical facility buildings for future retrofits. • Shelter Studies Evaluations of 29 buildings throughout the Hawaiian Islands were conducted in accordance with the requirements of the Department of Accounting and General Services (DAGS), Division of Public Works, Scope of Services and Procedure for Structural Assessment of Buildings for Hurricane Shelter Classification. The primary objective of these evaluations were to identify whether the structures substantially meets the wind load criteria for a Shelter rating of Type B or better. The evaluations also identify recommendations for any further incremental structural or nonstructural retrofits to achieve substantial compliance with Shelter Types B, A, and EHPA, where economically feasible. Four facilities on the Big Island were evaluated according to this procedure; the results of these studies are presented in Chapter 16. • Wind Map Improvements The building code now used in the County of Hawaii does not include any design requirements for amplified winds caused by topography. The International Building Code (IBC) 2006 Edition that will replace the code now used in the County introduces a new topographic factor and a wind directionality factor that in their default formulations would not give accurate results in Hawaii. This would lead to a high probability of incorrect design unless the State Building code amendments are adopted. The state of Hawaii amendments include several customized map products prepared for the building code in Hawaii County. Significant improvements in wind hazard mitigation can be accomplished through the use of wind speed-up mapping in local building codes and risk assessments. New wind maps incorporating this effect define a standard for a uniform level of protection for hurricane hazard throughout the County. Benefits include explicit quantification of wind-hazard and its mitigation through the identification of the severity of wind environments for planners and building designers that will significantly improve building performance. Determination of the wind hazard in topographically affected critical facility sites is essential for pre-disaster planning and emergency operations planning. Criteria for critical facility use and any necessary mitigation can then be objectively established. The overall effort will support goals of this plan to implement effective public safety planning and mitigation of coastal hazards. A 2008-2009 project sponsored by the State Office of Planning undertook the technical amendments necessary for the adoption of new wind speed design mapping provisions into the International Building Code 2006 and ASCE-7 standard by the County of Hawaii, which xvii Hawaii County Multi-Hazard Mitigation Plan