Probabilistic-based hurricane risk assessment and mitigation considering the potential impacts of climate change

Studies are suggesting that hurricane hazard patterns (e.g. intensity and frequency) may change as a consequence of the changing global climate. As hurricane patterns change, it can be expected that hurricane damage risks and costs may change as a result. This indicates the necessity to develop hurricane risk assessment models that are capable of accounting for changing hurricane hazard patterns, and develop hurricane mitigation and climatic adaptation strategies. This thesis proposes a comprehensive hurricane risk assessment and mitigation strategies that account for a changing global climate and that has the ability of being adapted to various types of infrastructure including residential buildings and power distribution poles. The framework includes hurricane wind field models, hurricane surge height models and hurricane vulnerability models to estimate damage risks due to hurricane wind speed, hurricane frequency, and hurricane-induced storm surge and accounts for the timedependant properties of these parameters as a result of climate change. The research then implements median insured house values, discount rates, housing inventory, etc. to estimate hurricane damage costs to residential construction. The framework was also adapted to timber distribution poles to assess the impacts climate change may have on timber distribution pole failure. This research finds that climate change may have a significant impact on the hurricane damage risks and damage costs of residential construction and timber distribution poles. In an effort to reduce damage costs, this research develops mitigation/adaptation strategies for residential construction and timber distribution poles. The costeffectiveness of these adaptation/mitigation strategies are evaluated through the use of a Life-Cycle Cost (LCC) analysis. In addition, a scenario-based analysis of mitigation strategies for timber distribution poles is included. For both residential construction and timber distribution poles, adaptation/mitigation measures were found to reduce damage costs. Finally, the research develops the Coastal Community Social Vulnerability Index (CCSVI) to include the social vulnerability of a region to hurricane hazards within this hurricane risk assessment. This index quantifies the social vulnerability of a region, by combining various social characteristics of a region with time-dependant parameters of hurricanes (i.e. hurricane wind and hurricane-induced storm surge). Climate change was found to have an impact on the CCSVI (i.e. climate change may have an impact on the social vulnerability of hurricane-prone regions)

Occupants’ adaptation and design parameters influencing behavioural actions of occupants in naturally ventilated sustainable timber buildings

Existing studies have examined occupants’ adaptation and various parameters affecting thermal comfort of occupants in different buildings. However, there are limited studies that have examined occupants’ adaptation and design parameters in naturally ventilated sustainable buildings, especially structural timber buildings. As a result, this study considers a comparative analysis of occupants’ adaptation and examines various design parameters influencing behavioural actions of occupants in naturally ventilated structural timber buildings. The study evaluates indoor spaces of two dwelling units in each of the two sustainable timber case study buildings located in Western Europe. The research employed analysis of architectural design of the buildings, on-site measurements, and a thermal comfort survey. The parameters measured during the on-site survey include temperature and relative humidity at one hour intervals for twelve days during the summer period. The findings were compared with design parameters such as natural ventilation, size of opening, floor-to-ceiling height, and floor area of the spaces. The results showed more than 85% of the occupants in dwelling units with smaller floor area tend to adapt better to the thermal environment than those living in dwelling units with bigger floor area. It appears that at least 75% of the occupants in spaces with natural cross-ventilation tend to be more thermally satisfied than occupants in spaces with single-sided ventilation. The findings also revealed the risk of summertime overheating tends to be significantly reduced (p<0.05) when spaces have natural cross-ventilation, higher floor-to-ceiling height, and a larger floor area. Finally, the results showed the adaptation of occupants in naturally ventilated buildings and the ability to use control to adjust the thermal environment and reduce the overall annual energy consumption in sustainable buildings. Keywords: architectural design, comparative study, occupants’ adaptation, design parameters, behavioural actions, naturally ventilated sustainable timber building

Normal neonatal TREC and KREC levels in early onset juvenile idiopathic arthritis

Objective: Dysregulated central tolerance predisposes to autoimmune diseases. Reduced thymic output as well as compromised central B cell tolerance checkpoints have been proposed in the pathogenesis of juvenile idiopathic arthritis (JIA). The aim of this study was to investigate neonatal levels of T-cell receptor excision circles (TRECs) and kappa-deleting element excision circles (KRECs), as markers of T- and B-cell output at birth, in patients with early onset JIA. Methods: TRECs and KRECs were quantitated by multiplex qPCR from dried blood spots (DBS), collected 2–5 days after birth, in 156 children with early onset JIA and in 312 matched controls. Results: When analysed from neonatal dried blood spots, the median TREC level was 78 (IQR 55–113) in JIA cases and 88 (IQR 57–117) copies/well in controls. The median KREC level was 51 (IQR 35–69) and 53 (IQR 35–74) copies/well, in JIA cases and controls, respectively. Stratification by sex and age at disease onset did not reveal any difference in the levels of TRECs and KRECs. Conclusion: T- and B-cell output at birth, as measured by TREC and KREC levels in neonatal dried blood spots, does not differ in children with early onset JIA compared to controls

Risk assessment and wind hazard mitigation of power distribution poles

This chapter discusses risk assessment of power distribution poles subjected to hurricane hazards and various mitigation strategies. Every year power outages due to wind storms cause an estimated $270 million in repair costs in the United States. Hurricane Irene left approximately 6 million residents without power along the east coast of the U.S. in 2011, causing an estimated$5 to $7 billion in damages. Risk assessment of power distribution poles is conducted considering various sources of uncertainties in the hurricane fragility, the effects of degradation of timber poles, and probabilistic wind models. Various hazard mitigation strategies are evaluated with a life-cycle cost analysis for their cost-effectiveness in reducing the vulnerability of poles due to hurricane winds. Certain mitigation strategies are found to have the potential to significantly reduce replacement costs due to hurricanes

Evaluation of impact of climate change on hurricane damage risks and adaptation strategies

This paper evaluates the potential impact of hurricane damage risks to buildings due to climate change and adaptation strategies. The analysis includes a probabilistic hurricane wind field model and a hurricane vulnerability model. There is a great uncertainty on the potential change in hurricane hazard patterns due to climate change. To represent this uncertainty and to investigate the potential impact of climate change, the paper explores the scenarios of increases of -5 to 10% in mean annual maximum wind speed over 50 years. The effects of regional development dynamics, the rate of retrofit, cost of retrofit, reduction in vulnerability after retrofit, and discount rate are investigated. This risk-cost-benefit analysis is vital in indentifying optimal and cost-effective adaption strategies to the potential adverse effects of enhanced greenhouse conditions. Miami-Dade County, Florida is used as a case study to evaluate the economic viability of various adaptation strategies. © 2010 American Society of Civil Engineers

A probabilistic-based framework for impact and adaptation assessment of climate change on hurricane damage risks and costs

This paper presents a probabilistic-based framework to assess the potential hurricane risks to residential construction under various wind speed change scenarios due to potential climate change. Every year hurricane (cyclone) hazards cause extensive economic losses and social disruption around the world. Annual hurricane damage in the United States (US) is around $6 billion in recent years. Hurricane intensity or/and frequency may change due to the increase in sea surface temperature as a result of climate change. Implications of the changing hazard patterns on hurricane risk assessment warrants an investigation to evaluate the potential impact of climate change. The framework includes probabilistic models of hurricane occurrence and intensity and conditional damage state probabilities (vulnerability model) for typical residential construction in the US, and an assessment of the cost-effectiveness of various climate change adaptation strategies. A case study of Miami-Dade County, Florida is presented to illustrate the framework under various scenarios of change in maximum annual wind speed over 50 years. Demographic information, such as median house value and changes in house numbers, and distribution of houses on different exposure, is used to estimate the time-dependent probable damage with or without possible climate change induced change in wind speed. This study shows that climate change may have a substantial impact on the damage and loss estimation in coastal areas, and that certain adaptation strategies can cost effectively decrease the damage, even if the wind speed does not change

Social vulnerability index for coastal communities at risk to hurricane hazard and a changing climate

This paper presents the development of the Coastal Community Social Vulnerability Index (CCSVI) in order to quantify the social vulnerability of hurricane-prone areas under various scenarios of climate change. The 2004-2005 Atlantic hurricane seasons is estimated to have caused $150 billion dollars in damages, and in recent years, the annual hurricane damage in the United States is estimated at around$6 billion. Hurricane intensity or/and frequency may change due to the increase in sea surface temperature as a result of climate change. Climate change is also predicted to cause a rise in sea levels, potentially resulting in higher storm surges. The CCSVI combines the intensity of hurricanes and hurricane-induced surge to create a comprehensive index that considers the effects of a changing climate. The main contributing factors of social vulnerability (such as race, age, gender, and socioeconomic status) in hurricane-prone areas are identified through a principal components analysis. The impact of social characteristics on the potential hurricane damage under various scenarios of climate change are evaluated using Miami-Dade County, Florida, as a case study location. This study finds that climate change may have a significant impact on the CCSVI. © 2011 Springer Science+Business Media B.V

Regional loss estimation due to hurricane wind and hurricane-induced surge considering climate variability

This paper presents a framework to assess the potential hurricane damage risks to residential construction. Studies show that hurricane wind, frequency and/or hurricane-induced surge may change as a result of climate change; therefore, hurricane risk assessments should be capable of accounting for the impacts climate change. The framework includes a hurricane wind field model, hurricane-induced surge height model and hurricane vulnerability models. Three case study locations (Miami-Dade County, FL; New Hanover County, NC and Galveston County, TX) are presented for two types of analyses: annual regional loss estimation and event-based regional loss estimation. Demographic information, such as median house value and changes in house numbers, and distribution of houses for different exposures, is used to estimate the time-dependent probability of damage with or without possible climate change-induced change in wind speed, frequency and/or surge height. Through both analyses, it was found that climate change may have a significant impact on regional hurricane damage losses

Hurricane risk assessment of power distribution poles considering impacts of a changing climate

Storm-related power outages cause approximately $270 million per year in repair costs in the United States. As a result of increasing sea surface temperatures caused by the changing climate, hurricane patterns (i.e., intensity/frequency) may change; however, there is much uncertainty as to how climate change may affect hurricane patterns. Implications of the changing hazard patterns on hurricane risk warrants an investigation to evaluate the potential impact of climate change on power distribution pole failure. This paper proposes a probabilistic framework to evaluate the vulnerability of power distribution poles to hurricanes under the potential impact of a changing climate. Two methods for the design of distribution poles in the United States, the National Electric Safety Code method and the ASCE method, are considered to investigate the difference of the vulnerability of a distribution pole subjected to hurricane hazard. The framework includes a reliability analysis of the designed power distribution poles using fragility analysis, the effects of degradation of timber poles, probabilistic wind models, and an assessment of the potential impacts of climate change on the annual failure probability of power distribution poles. This paper finds that climate change may have a significant effect on the structural failure probabilities of distribution poles. The age of the poles has a significant impact on the reliability of power distribution poles, which warrants the exploration of cost-effective methods to determine when a distribution pole should be replaced to ensure adequate strength to withstand wind loads

Risk-based economic assessment of mitigation strategies for power distribution poles subjected to hurricanes

This paper presents a risk-based framework to assess the hurricane damage risks to distribution poles, and investigates the risks, costs and benefit of different mitigation strategies. It is estimated that power outages due to storms cause approximately $270 million in repair/replacement costs annually in the USA. Hurricane Irene alone left approximately 6 million residents without power along the east coast of the USA in 2011, causing an estimated$5-$7 billion in damages. These high repair/replacement costs warrant an investigation of mitigation strategies that may aid in reducing replacement and damage costs. This paper describes the reliability analysis of typical timber distribution poles and probabilistic wind models to determine failure probabilities for specific locations. Furthermore, in order to more accurately portray the behaviour of distribution poles, the proposed framework includes the degradation and service-proven reliability of timber distribution poles. Four mitigation strategies are developed, and the cost effectiveness of each strategy is evaluated. In order to assess the cost effectiveness, a life cycle cost analysis is conducted for each mitigation strategy. This paper finds that appropriate mitigation strategies can reduce replacement costs of distribution poles associated with hurricane wind by 2060