HAZUS-MH Hurricane Model Methodology. I: Hurricane Hazard, Terrain, and Wind Load Modeling Peter J. Vickery 1 ; Jason Lin 2 ; Peter F. Skerlj 3 ; Lawrence A. Twisdale Jr. 4 ; and Kevin Huang 5 Abstract: An overview of the hurricane hazard model, terrain model, wind pressure, and windborne debris models used in the HAZUS-MH hurricane model is presented. These models represent the first three of five major component models used in HAZUS for the prediction of damage and loss to buildings subjected to hurricanes. The five model components are the hurricane hazard model, terrain model, wind load model, physical damage model, and loss model. These models have been validated, wherever possible, through the use of historical data for landfalling hurricanes, wind tunnel test results, field observations of hurricane induced damage and insurance loss data. The HAZUS hurricane model represents an advancement in the state-of-the-art over other hurricane loss prediction models in that it estimates wind induced loads, building response, damage and loss, rather than simply using historical loss data to model loss as a function of wind speed. DOI: 10.1061/ASCE1527-698820067:282 CE Database subject headings: Models; Hurricanes; Wind loads; Damage. Overview of HAZUS-MH Hurricane Model The HAZUS-MH Hurricane Model HM has been developed using wind engineering principles to enable detailed estimates of possible damage and loss to buildings and their contents due to wind storms. The model uses an existing peer reviewed hurricane hazard model that models the entire track and wind field of a hurricane or tropical storm Vickery et al. 2000a,b that has been extensively validated through comparisons of simulated and ob- served wind speeds using data from over 140 anemometer loca- tions. The hurricane hazard model simulates the entire hurricane track, whether the storm makes landfall or not. The hurricane wind field model has been extended to allow estimating rainfall rates are used to estimate the amount of water entering buildings through broken windows and doors and is a significant component of building damage. HAZUS contains the first direct nationwide database of sur- face roughness, which is a critical component in modeling wind effects, damage, and loss to buildings. The terrain model was developed using existing information on land use land cover LULC combined with estimates of surface roughness for each land use type obtained by assigning roughness values to a LULC class using aerial photographs of sample LULC classes. The HAZUS physical damage model is an engineering-based load and resistance analysis of building component performance. Both wind-induced pressure and windborne debris impacts are modeled. The physical damage model estimates the damage to the building primarily in terms of failure of building envelope com- ponents, rather than failure of the structural frame, which is rela- tively infrequent, and occurs after failure of building enveloped components. Structural failures that are considered include the failure of roof–wall connections in wood-frame and masonry con- struction, failure of wood and masonry walls, wall and roof struc- ture failures in manufactured housing, failures of long span open web steel joists through buckling of the top chord, or failure of the joist wall connections. The loss model computes losses to a building using the mod- eled building damage states combined with empirical cost estima- tion techniques for building repair and replacement. Contents loss is based on an empirical model that relates contents damage to building envelope performance. The cost associated with the loss of use of the building is estimated based on the time required to repair the building. The building, contents, and loss of use mod- eling components have been validated with insurance loss data. The load–resistance-damage-loss methodology used in the HAZUS model provides the framework needed to reliably exam- ine the effect of mitigation in a quantitative manner by modeling building components with increased resistances. For regional damage and loss assessments in HAZUS, fast running damage and loss functions have been developed for a number of building classes. These functions are used to estimate losses for each building class or occupancy class modeled in HAZUS. The over- all approach taken in the development of the HAZUS HM is described in Fig. 1. As indicated in the figure, each component in the model has been validated, wherever possible, through com- parisons with field observations and wind tunnel data. This paper presents an overview of the hurricane hazard model, the terrain modeling, and the modeling of the wind- induced pressures and debris impact probabilities. 1 IntraRisk, Applied Research Associates, Raleigh, N.C. 27615 corresponding author. E-mail: pvickery@ara.com 2 Risk Management Solutions, Newark, CA. 3 Partner Re, Zurich, Switzerland. 4 IntraRisk, Applied Research Associates, Raleigh, N.C. 27615. 5 Ace Tempest Re, Bermuda. Note. Discussion open until October 1, 2006. Separate discussions must be submitted for individual papers. To extend the closing date by one month, a written request must be filed with the ASCE Managing Editor. The manuscript for this paper was submitted for review and pos- sible publication on June 28, 2004; approved on July 6, 2005. This paper is part of the Natural Hazards Review, Vol. 7, No. 2, May 1, 2006. ©ASCE, ISSN 1527-6988/2006/2-82–93/$25.00. 82 / NATURAL HAZARDS REVIEW © ASCE / MAY 2006