Improved Hawaii Basic Design Wind Speed Maps Including Topographic Effects

The state of Hawaii is a series of mountainous islands with a topography that is much more complex than the simple isolated hills and escarpments included in ASCE standard ASCE/SEI 7-22 (Minimum design loads and associated criteria for buildings and other structures, ASCE 7). Hawaii state and county building codes have incorporated topographic wind speed mapping since 2007. In 2010, ASCE 7-10 recognized Hawaii as a special wind region. The design wind speed maps, $K_{zt}$ maps, and site-specific directionality factors as adopted in Hawaii’s state building codes constituted the “special $K_{zt}$ topographic effect adjustments” of the authority having jurisdiction that were referenced in ASCE 7-10. In ASCE 7-16 and ASCE 7-22, microzoned wind speed maps for Hawaii, including the effect of topography and directionality, were incorporated for strength design return periods. This paper provides information on the development of an improved generation of higher-resolution basic design wind speed maps for the state of Hawaii, including better accuracy of topographic and directionality effects. The digital format of these wind speed maps can be readily incorporated into the ASCE 7 digital hazard tool interfaces.