Hurricane Vulnerability of Multi-Story Residential Buildings in Florida G. L. Pita, J.-P. Pinelli, C.S. Subramanian Florida Institute of Technology, 150, W. University Blvd, Melbourne, Florida 32901 United States of America, Ph.: 321-674-8085, pinelli@fit.edu K. Gurley University of Florida, Gainesville, Florida, United States of America S. Hamid Florida International University, Miami, Florida, United States of America ABSTRACT: In recent years, a multi-disciplinary team has developed the Florida Public Hurricane Loss Model. The model combines state-of-the-art technology in the fields of meteorology, engineering, actuarial science, and computer science to predict hurricane-induced losses for single-family homes. The model is now being extended to cover multi-family buildings ranging from a few stories to the high rise condominiums typically found lining the beaches of South Florida. These are engineered structures with a large variety of structural types, shapes, and heights. To address the challenge of predicting hurricane losses for these structures, the meteorologists are developing a new 3D model of the wind field, and the engineers are working on a new vulnerability model to incorporate the effects of height and associated air jets on the buildings’ vulnerabilities. The first step in this process is to carry out a comprehensive survey of the multi-family buildings stock in Florida, to identify the most prevalent characteristics of the structures, their relationship to hurricane risk, and their geographic distribution. This paper describes the outcome of the exposure study, with an analysis of the hurricane risk attached to multi-family, multi-story buildings and a comparison to single-family homes. The authors conclude with a description of the strategy developed to quantify the potential hurricane losses associated with a portfolio of multi-unit structures including building and contents losses, and additional living expenses. The first task was to perform a comprehensive 1 INTRODUCTION survey of the current commercial-residential building stock in Florida in order to provide the vulneraHurricanes constitute a part of Floridians’ everyday bility model with the typical buildings, their characexperience since historically they have represented a teristics and their prevalence. The survey will constant threat to their lives and properties. In recent identify the building types that are representative of years, significant efforts have been made by the State the stock and whose vulnerability will be simulated. of Florida to reduce hurricane-induced building lossThe resulting statistics will also be used for es, including the development of a loss model. A weighting or averaging the vulnerability of different team, composed of engineers and scientists from the building types around the state. National Oceanographic and Atmospheric AdminTo perform the survey, the county property apistration (NOAA), Florida International University, praisers’ databases were the only source of inforFlorida Institute of Technology and the University of mation available. The counties that represent most of Florida, among others, has produced the Florida the State’s building inventory were contacted. TwenPublic Hurricane Loss Model (FPHLM). This is the ty-two counties provided their commercialonly model specifically designed to predict residenresidential database in response to the data call. In tial insured losses which is accessible for scrutiny by these databases, property appraisers classify the the scientific community and the public. The model properties either as multi-family residential buildpredicts the losses of residential homes and has been ings (MFR) or as condominiums. MFR buildings certified by the Florida Commission on Hurricane comprise duplex, triplex and quadruplex buildings. Loss Methodology as an acceptable model for proAround 50% of the databases had some useful injecting hurricane loss costs (FCHLPM 2007). The formation (Table 1) on MFR buildings, and around structure of the model as well as validation and cali20% had some useful information on condos. bration results have been described elsewhere (PiIn addition to the results of the exposure survey, a nelli et al 2003, Powell 2005, Pinelli et al 2004, vulnerability model is described. There is little, if Chen et al 2004, Pinelli et al 2006, Pinelli et al any, information published on multi-story buildings’ 2007). The model is now being expanded to include vulnerability (NIBS 2002). This situation is due to multi-story commercial-residential buildings. the fact that many models are proprietary so the details are not open to the public. On the other hand, many models base their damage models in regression analysis from claim data. In this paper an engineering-based approach to calculate damage is discussed. After a threshold of exterior damage has occurred, interior damage is triggered and then it propagates following different rules. The aggregation of both damages accounts for the buildings’ total damage assessment. The authors are currently working on a technique to simulate both exterior and interior plus contents damage. A brief discussion on their work is included. 2 BUILDING SURVEY METHODOLOGY Previous work has been done surveying Florida’s single family residential buildings using the information provided by the property appraisers (Intrarisk 2002, Zhang 2003). Also, California appraisers’ information has been used for damage estimation (Kiremidjian 1994). To our knowledge, no survey results on low, mid and high rise buildings have been published. For the survey, the authors classified the buildings within the range of 1-3 stories as low rise and buildings with 4 stories or more were classified as mid-to-high rise. MFR buildings fall under the low rise classification, while condos could go either way. Unanwa 1997 uses a similar definition in his study. 2.1 Collected information The properties of interest to this study are related with the building’s capability to resist hurricane wind damage. In addition to external characteristics, interior characteristics, even though not related to strength, are also important because they are linked to interior damage propagation. The information that was collected includes: Exterior walls’ material Interior walls’ material Roof type Roof cover Floor covering Year built Number of stories 2.2 Data sources and limitations It was not possible to obtain useful information from every available county. For example, the most densely built counties, Miami-Dade and Broward counties do not record the information needed to characterize the low-rise and mid-high rise building stock. In addition, there is no common data format among the counties. Although there are similarities in database’s structure, the way the data fields relate with each other, the type and precision of collected data (e.g., very few counties report Exterior Insula- tion and Finish Systems or EIFS, as a category) and the codes used to classify information differ from county to county. Judgment calls were necessary in order to make data from different counties comparable and to interpret the results. Another issue is that some counties do not share information on buildings with an above-the-average dollar value due to owners’ restrictions. Usually these buildings are high-rises with more than 9 floors. This does not mean that there are not buildings that are higher than 9 stories in the county; it is just that the property appraisers do not share the information. This survey may not be free of error because of the aforementioned shortcomings. As mentioned earlier the appraisers do not classify buildings as low-rise and mid-high rise but as MFR and condos. Buildings classified as condo may have a number of stories that range from one to many stories while MFR have only 1 to 3 stories. This means that condos include low-rise as well as mid-high rise buildings while MFR include low rise buildings only. Thus, it is necessary to split condo building information into low rise and mid-high rise buildings. During this process assumptions were made since the county may have information on MFR characteristics but not on condos, since the appraisers record information on individual condo units but not on the buildings that house them. When the condo information is missing for a particular county (Table 1), it was assumed that the distribution of low rise condo characteristics such as exterior/interior wall, etc. follow the same distribution as that of MFR. This assumption was validated against the case when information on both MFR and condos buildings was available. Given the aforementioned shortcomings, the results are subject to error. Table 1: Number of buildings (ND: no data available) County Palm Beach Hillsborough Orange Pinellas Duval Brevard Polk Lee Volusia Pasco Seminole Collier Marion Lake Leon Alachua Saint Lucie Osceola Bay Saint Johns Monroe MFR 11430 14417 11563 10573 5725 3532 1068 16399 3500 1274 3663 2090 2393 2700 2051 1187 1733 1009 1750 3125 3452 Low-rise condos M-H rise condos 6372 1208 ND 7475 ND 2186 574 ND 2898 414 ND 1452 217 ND ND ND ND 6192 2500 ND ND ND ND ND ND ND 3 LOW-RISE RESULTS A snapshot of the 2006/2007 situation of Florida’s building portfolio is in the next sections. The number of residential-commercial buildings is significantly smaller than for single-family residential homes. The number of commercial-residential buildings is only around 7% of single family-residential homes (Zhang, 2003). However, their total exposure value is around 30% of the single homes exposure . 3.1 Exterior Walls The existing information indicates that exterior wall materials follow a pattern as shown in Figure 1 and detailed in Table 2. In south-coastal Florida, there is a belt-area where concrete block (CB) walls prevail from 70% to 90%. This is not surprising given the geographical situation, the population experience with hurricanes and the building codes In central Florida, the proportion of concrete block varies between 40% and 70%. The smallest proportion of concrete block exterior walls occurs in the northern part of the peninsula and the panhandle. Thus, three different zones could be defined: southcoastal belt, central and north Florida. Overall average is: 58% CB and 39% wood. It was found that the low-rise buildings’ exterior wall materials’ percentages show a very similar distribution as those of the residential buildings as reported in Zhang 2003 (58% for CB). Table 2: Exterior Wall distribution - Low rise County Palm Beach Orange Pinellas Duval Brevard Lee Volusia Pasco Marion Lake Leon Alachua Saint Lucie Osceola Bay Saint Johns Wood 25% 46% 24% 51% 35% 12% 56% 16% 27% 43% 57% 30% 23% 51% 48% 78% CB 71% 49% 76% 49% 65% 84% 41% 84% 73% 55% 33% 52% 75% 49% 36% 22% Metal Glass Concrete 2% 3% Other 2% 2% 3% 1% 2% 1% 10% 17% 1% 1% 9% 6% 3.3 Roof type The preferred roof type in the studied counties is gable/hip with an average of 90% of low-rises and a standard deviation of 8%. See Table 3. Flat roofs follow with an average of 4% and standard deviation of 5%. Just three counties (Volusia, Marion and St. Lucie) split the records between gable and hip. For them the proportions of different roofs are seen in Table 4. Table 3: Roof Types - Low rise County Gable/Hip Flat Steel Concrete Wood Shed Other Orange 96% 1% 2% 1% Pinellas 91% 10% Duval 91% 8% Brevard 85% 11% 2% 2% Lee 91% 4% 4% Volusia 94% 6% 1% Pasco 97% 2% Marion 95% 1% 3% Leon 94% 1% 1% 2% 1% Saint Lucie 88% 11% Osceola 97% 2% Bay 95% 2% 2% 1% Saint Johns 85% 3% 12% Monroe 68% 18% 5% 9% Table 4: Roof proportions - Low rise County Gable Hip Flat Volusia 73% 21% 6% Marion 69% 26% 1% St. Lucie 67% 21% The average for low rise buildings, gable roof is 70% while for hip roofs is 23%. These average gable roof proportions match fairly well with the results of Zhang 2003 (only surveys Brevard, gable roof 65%). Figure 1: Exterior Wall (concrete block) distribution 3.2 Interior Walls Interior walls show uniformity all over the studied counties. Drywall is the preferred material with an average of 93% of low-rises and standard deviation of 7%. 3.4 Roof cover Of all the studied counties, shingle cover is the most widespread roof cover with an average of 77% of low-rises and a standard deviation of 16%. The other roof covers, i.e. tiles, membrane, gravel and metal vary between 4% and 10% adding up for a total of 24%. See Table 5. For residential buildings, Zhang (2003), presents around 67% for shingles, 20% for tile and for Monroe, 26% Metal roof cover. In this case, the roof cover proportions are fairly close again with that author. more than 50% of the low-rise building stock, but only 30% of the exposure value. 2 story buildings represent almost 50% of the exposure. 60% Table 5: Roof Covers – Low rise Tiles Gravel Membrane Metal Concrete Other 13% 9% 1% 4% 11% 1% 15% 4% 6% 1% 8% 20% 17% 10% 1% 2% 8% 1% 9% 6% 2% 2% 2% 2% 1% 1% 1% 3% 2% 6% 4% 4% 2% 16% 2% 4% 2% 1% 4% 2% 14% 4% 1% 5% 3% 4% 3% 9% 3% 44% 11% 1% 3.5 Floor finishing % No. Buildings & % of Exposure County Shingle Orange 77% Pinellas 83% Duval 75% Brevard 72% Lee 70% Volusia 83% Pasco 88% Marion 95% Lake 62% Leon 91% Saint Lucie 75% Osceola 91% Bay 81% Saint Johns 87% Monroe 28% No. of buildings Low-Rise Exposure 50% 40% 30% 20% 10% 0% 0 1 2 3 4 Number of Stories Figure 3: No. of stories and exposure - Low rise Table 6: Year Built - Low Rise Carpet is the most common floor covering, as expected, with an average of 67% of low-rises and standard deviation of 27%. Vinyl is the next with average 13% and standard deviation of 23%. Finally Wood floor has an average of 7%. 3.6 Year built – Low rise The year of construction of a building is a key indicator of its vulnerability to hurricanes. Age will be used later to assign a certain level of strength to building types. The average of all the processed counties indicates that almost 2/3 of the building stock was built before 1983. The rest is almost linearly distributed between 1983 and the present. See Figure 2 and Table 6. County Pre - 1970 1971-1983 1984-1992 1993-2002 Post 2003 Palm Beach 29% 35% 25% 7% 1% Hillsborough 27% 36% 22% 10% 5% Orange 13% 30% 35% 17% 4% Pinellas 42% 34% 15% 5% 4% Duval 85% 8% 7% Brevard 25% 28% 35% 10% 4% Polk 27% 35% 14% 3% 2% Lee 9% 32% 22% 15% 22% Volusia 19% 31% 33% 8% 9% Pasco 24% 57% 12% 1% 7% Seminole 13% 35% 32% 18% 2% Collier 14% 9% 21% 49% 7% Marion 4% 33% 41% 13% 8% Alachua 17% 48% 18% 13% 3% Saint Lucie 46% 30% 11% 9% 4% Osceola 12% 24% 38% 18% 8% Bay 16% 37% 27% 15% 6% Saint Johns 13% 11% 25% 9% 43% Monroe 62% 24% 8% 5% 2% 35% 30% 4 MID - HIGH-RISE BUILDING SURVEY Proportion 25% 20% 15% 10% 5% 0% Pre - 1970 1971-1983 1984-1992 Year Built 1993-2002 2003-2007 Figure 2: Average Year built - Low rise 3.7 Number of stories – Low rise The 1 story structures predominate among low rise buildings, with some local variations. In Figure 3 the relative proportion of buildings according to number of stories is shown. 1-story buildings represent Survey results for buildings with 4 or more stories are more debatable than for low-rise buildings results since few counties keep useful records for high rise buildings, from the point of view of vulnerability. It was possible to extract results only from Palm Beach, Pinellas, Brevard and Lee counties whose approximate number of buildings are shown in Table 1. 4.1 Mid - high rise buildings results For mid-high rise buildings the prevalent exterior wall is concrete block. See Table 7. For interior wall there was no available information. Based on the information of Lee and Brevard County, it was found that the predominant roof type is the flat roof. See Table 8. The average proportion of flat roof is 66% of mid-high rises with a standard Table 7: Exterior Walls – Med/High Rise County Pinellas Brevard Lee Wood 2% 1% CB 98% 98% 99% Other 1% 50% 45% 40% 35% 30% Proportion deviation of 14%. On the other hand gable/hip roofs account for 34% on average of the buildings with a standard deviation of 14%. In only one county (Brevard), it was possible to study the building’s roof cover. It was found that the preferred material are varieties of asphalt membrane in 78% of the mid-high rises, tiles in 11% and shingle in 8% of buildings. Given the lack of data, it is not possible to draw further conclusions. Moreover, more research needs to be done on the roof cover of high-rise buildings in the most important counties since the nature of downtown windborne debris is highly dependent on roof cover (Minor 1994). The relative average of buildings per number of stories (in Palm Beach, Pinellas, Brevard and Lee County) is shown in Figure 4. As expected, the proportion decreases with the number of stories. In Table 9 and Figure 5 a snapshot of the current year built of building stock is shown. There, up to 45% of the buildings were built in the period of 1971-1983. This information is important to assign strength level to the different vulnerability models. 25% 20% 15% 10% 5% 0% Pre - 1970 1971-1983 1984-1992 1993-2002 2003-2007 No. of Stories Figure 5: Year built - Med/High rise 5 BUILDING EXPOSURE The number of buildings cannot be used as the unique criteria to weight the prevalence of a particular building type. There are buildings that have a considerably higher monetary value although they are less in number. Figure 6 shows the relative importance of each building classification according to number and value. 80% Table 8: Roof Type - Med/High rise Flat 76% 56% 60% 50% Proportion County Gable/Hip Brevard 24% Lee 43% 40% 40% 35% 30% 30% Proportion Avg Money Exposure Avg No. of Buildings 70% 20% 25% 10% 20% 0% 15% MFR LR Condo Building Classification M/HR Condo 10% Figure 6: Exposure compared with No. of Buildings for all classifications 5% 0% 4 5 6 7 8 9 >9 No. of Stories Figure 4: No. Stories relative percentage average – Midhigh rise Table 9: Year Built - Med/High Rise County Pre - 1970 1971-1983 1984-1992 1993-2002 2003-2007 Palm Beach 6% 46% 40% 7% 1% Pinellas 9% 54% 14% 12% 11% Brevard 2% 34% 31% 22% 10% Lee 3% 42% 15% 24% 17% It shows that although the number of mid-high rise buildings is smaller, they account for 30% of the building stock, so they need to be considered carefully in the vulnerability model. As stated by Pielke and Landsea (1998) and Pielke et al (2008), the wealth of population and value of buildings is an important component of vulnerability. In the case of low-rise buildings that is true as well. Figure 7 shows that although 2-story buildings are almost half the number of 1-story’s, nevertheless their exposure is higher than for 1-story buildings. 60% Low-Rise Exposure 50% No. of buildings % of Exposure 40% 30% 20% 10% 0% 0 1 2 Number of Stories 3 4 Figure 7: Exposure value compared to No. of Buildings for Low-Rise buildings in 4 counties Number and value can be used to weight the importance of the different types of low rise as shown in Figure 8. It shows that the 2-story buildings have the same weight than the 1-story in the vulnerability of the low-rise stock. the strategy needs to be applicable to a wide variety of buildings that differ in type of façade, number of stories, shape, and number of units (apartments). Given this variety of buildings, a modular approach that models individual apartment units instead of whole buildings seems appropriate. Unit types that reflect those frequently found in Florida’s buildings needs to be defined. That task will be done using the survey results. The authors are currently building and testing an external damage (ED) module that calculates the ED to an average apartment unit. The units are classified taking into account the following factors: Wall type, position, size (survey results will be shown in a future paper), and year built. The unit position will be determinant on how the wind speeds interact with the unit an also how the interior damage propagates. There are at least two positions that capture the above mentioned, those are: corner units and middle units (Figure 9), with one set for intermediate floors, and one set for the top floor directly under the roof. 60% Weighted Importance % of Weighted Exposure 50% 40% 30% 20% 10% 0% 0 1 2 Number of Stories 3 4 Figure 8: Weighted exposure of Low-rise buildings 6 MODELING STRATEGIES The survey shows that low-rise buildings have characteristics very similar to the single-family residential buildings. Accordingly, the damage modeling strategy for low rise will be very similar, if not identical, to the strategy followed for residential single family homes reported elsewhere (Pinelli et al 2003). On the other hand, survey results suggest that given the importance of mid-high rise buildings a particular vulnerability approach, different to that of lowrise buildings, needs to be created. The new vulnerability approach for mid-high rise buildings needs to consider the influence of the buildings’ number of stories, as well as other characteristics reported in the survey results. In particular, Figure 9: Building plan view with position of unit types. Modules representing typical middle or corner units, for different types of façade (glass, masonry, EIFS, etc), and of an average size will be subjected to wind speeds of varying direction and increasing magnitude through Monte Carlo simulations. The approach will produce vulnerability matrices for every type of units. Given a building with a certain number of stories and number of units per story, the total external damage will be an aggregation of the damage to individual units, based on the wind speed information from the wind model. 6.1 Propagation criteria In addition to calculating and aggregating the ED of mid-high rise buildings units, the modular approach will include a propagation rule for interior plus utilities damage (IUD). Total average damage Di has three components, namely, average exterior damage DiE , average interior damage DiI and the average utilities damage DiU such that Di DiE DiI DiU (1) A propagation scheme which accounts for the IUD damage triggered by exterior damage and the interaction of ID damage between adjacent units, is currently under study. The principal object is to analyze how the exterior damage triggers the internal damage and how this propagates inside buildings of any given number of stories and units per floor (survey results to be shown in a future paper). The overall procedure is shown in Figure 10. At the end of the process a 4-dimensions tensor that will account for all the combined possibilities will be available. To assess the internal damage of a single building from an insurance portfolio it will be necessary to know 1) the number of stories, 2) the number of units per floor, 3) exterior damage. Figure 11: Finite differences grid. Every node is a condo unit 0 0 0 0.03 0.02 0 0.10 0.06 0 1 0.33 0.11 0 0 0.09 0.05 0 Units damage 0 0 Exterior Damage 0 Figure 12: Building plan view layout in Excel ® Figure 10: Interior damage propagation scheme The propagation engine is at the heart of the interior damage model. A first approach is presented here. At present it deals with water propagation only. The main questions to be addressed are the location of the damage and its magnitude. It can be shown that the location is a function of the magnitude. The model first determines the places where the water penetrates. Second, in those places where there is water, it computes the internal damage as a function of water content. A finite differences version of the Laplace equation was adopted to model water propagation (Figure 11). It was tested on a preliminary simple discretized building plan-layout (Figure 12) implemented in a spreadsheet in Excel® (Figure 13). The yellow cells represent the layout of a typical condo floor with 6 appartment units. The orange cell indicate whether the unit has external damage (1) or not (0). The numbers in each yellow cell represent the percentage of IUD. They are computed based on equation (2), where φi,j represents the water content in the unit i,j (represented as a node) The implementation of the algorithm is shown in Figure 13. Preliminary assessment indicates that an acceptable error is reached with 5 iterations or less. i, j 1 i1, j i1, j i, j 1 i, j 1 4 (2) Figure 13: Detail of the equation in Excel® A relationship (still under consideration) to account for vertical propagation (leakage) was also developed. It intends to capture the water propagation from top floor to bottom floor. Some challenges are being addressed currently like the apparentpermeability of the buildings. This is a work in progress and additional results will be shown in subsequent papers. 7 CONCLUSIONS The results of a survey carried out on Florida’s low rise and mid-high rise buildings by the engineering team of the FPHLM have been presented and discussed. The survey results are valuable for defining building types to be analyzed by the vulnerability model and also to average the resulting vulnerabilities when no specific structural information is available for a given building. The quality of this type of survey would greatly improve if certain uniform data collection and archiving measures would be adopted to enhance the data collection in such a way that it will be useful not only for tax assessment purposes, but also for the catastrophe modeling community. The authors also presented a novel modular approach to assess exterior and interior hurricaneinduced damage for mid to high rise building of any type and number of stories. The advantages of the approach are its simplicity and its versatility. It is a work in progress. The final challenge will be to validate the approach against actual hurricane losses. 8 ACKNOWLEDGMENTS The authors want to acknowledge the invaluable help of the staff of the different Florida counties tax property appraiser offices. The help of Tim Johnson (FIT), Fausto Fleites (FIU), HsinYu Ha (FIU) and Paul Austin (FIT) is gratefully appreciated. This research is supported by the State of Florida through a Department of Financial Services (FDFS) grant to the Florida International University International Hurricane Research Center. The opinions, findings, and conclu- sions expressed in this paper are not necessarily those of the FDFS. 9 REFERENCES Chen, S.C. Gulati, S. Hamid, S., Huang, X., Luo, L., Morisseau-Leroy, N., Powell, M.D., Zhan, C., Zhang, C. 2004, A Web-Based Distributed System for Hurricane Occurrence Projection. Software Practice & Experience, 34, 549-571 Florida Commission on Hurricane Loss Projection Methodology (FCHLPM) 2007. Florida Public Hurricane Loss Model Acceptability Notification. Available on http://www.sbafla.com/methodology/index.asp IntraRisk (2002), Development of Wind Resistive Features of Residential Structures. Version 2.2. Applied Research Associates, Inc. Kiremidjian, A. (1994), Methods for regional damage estimation. Earthquake Engng., Proc. 10th World Conference. Minor, J.E. (1994), Windborne debris and the building envelope. Journal of Wind Engineering and Industrial Aerodynamics. 53(1994) 207-227. Pielke, R.A., Landsea, C.W. (1998), Normalized Hurricane Damages in the United States: 1925-95. Climate and Weather, 13, 621-631 Pielke, R.A., Gratz, J., Landsea, C.W., Collins, D., Saunders, M.A., Musulin, R. (2008), Normalized Hurricane Damage in the United States: 1900-2005. Natural Hazards Review, 9 (1), 29 – 42. Pinelli, J-P., Subramanian, C., Zhang, L., Gurley, K., Cope, A., Simiu, E., Filliben, J.J., Diniz, S., Hamid, S. 2003. A Model to Predict Hurricanes Induced Losses for Residential Structure, Proceedings, ESREL 2003, Maastricht, The Netherlands. Pinelli, J-P., Simiu, E., Gurley, K. , Subramanian, C., Zhang, L., Cope, A., & Filliben, J. 2004. Hurricane Damage Prediction Model for Residential Structures, Journal of Structural Engineering, ASCE, Vol. 130, No 11, pp 1685-1691. Pinelli, J-P., Subramanian, C., Artiles, A., Gurley, K. & Hamid, S. 2006. Validation of a probabilistic model for hurricane insurance loss projections in Florida, Proceedings, ESREL 06, Estoril, Portugal, September 18-21 Pinelli, J-P., Subramanian, C.S., Garcia, F., Gurley, K. 2007. A study of hurricane mitigation cost effectiveness in Florida. Proceedings ESREL 2007, Stavanger, Norway, June 25-27. Powell, M., Soukup, G., Cocke, S., Gulati, S., MorisseauLeroy., N., Hamid, S., Dorst, N., Axe, L. 2005, State of Florida hurricane loss projection model: Atmospheric science component. Journal of Wind Engineering and Industrial Aerodynamics, 93, (8), 651-674. Zhang, L. (2003) Public Hurricane Loss Prediction Model: Exposure and Vulnerability Components. M.S. Thesis. Civil Engineering Department. Florida Institute of Technology.