@article {bnh-6276, title = {Improving the resilience of existing housing to severe wind events - annual report 2018-19}, number = {524}, year = {2019}, month = {12/2019}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

This project will provide practical structural retrofits that will make a significant improvement in the performance of Pre-80s (Legacy) houses to wind loads. The major activity carried out in 2018-19 by the CTS-JCU and GA has been progressing the VAWS software package using wind loading and structural response and other test data:

This project has also provided advice to the Queensland Government Household Resilience Program which provides funding to help eligible home owners improve the resilience of their homes against cyclones. This program is managed by the Queensland Department of Housing \& Public Works (QDHPW) and commenced in late 2018. Eligible home owners can apply to receive a Queensland Government grant of 75\% of the cost of improvements (up to a maximum of $11,250 including GST. About 2000 houses have been retrofitted.

}, keywords = {building resilience, cyclones, Emergency management, engineering, Housing, severe wind, storms, structural design}, issn = {524}, author = {John Ginger and Korah Parackal and Martin Wehner and Hyeuk Ryu and David Henderson and Mark Edwards} } @article {bnh-6333, title = {Model for assessing the vulnerability of Australian housing to windstorms - VAWS}, number = {529}, year = {2019}, month = {12/2019}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

Modelling the vulnerability of houses in windstorms is important for insurance pricing, policy-making, and emergency management. Models for Australian house types have been developed since the 1970s, and have ranged from empirical models to more advanced reliability based structural engineering models, which provide estimates of damage for a range of wind speeds of interest. This report describes the development of a software program: Vulnerability and Adaption to Wind Simulation (VAWS), which uses probability based reliability analysis and structural engineering for the loading and response coupled with an extensive test database and field damage assessments to calculate the damage experienced by selected Australian house types.\ \ 

}, keywords = {building resilience, cyclone, Emergency management, engineering, severe wind, wind modelling}, issn = {529}, author = {Korah Parackal and Martin Wehner and Hyeuk Ryu and John Ginger and David Henderson and Mark Edwards} } @mastersthesis {bnh-6247, title = {Simulation and analysis of surface wind fields during landfalling tropical cyclones}, volume = {Doctor of Philosophy}, year = {2019}, month = {06/2019}, school = {University of Queensland}, type = {Doctorate}, address = {Brisbane}, abstract = {

Tropical cyclones (TCs) are rotating atmospheric vortices characterised by high wind speeds thatpose a major threat to people and infrastructure in coastal communities. To minimise their impacts,the winds in the lowest part of the TC boundary layer (TCBL) must be adequately understood. Thisunderstanding enables engineers to make rational decisions around building design in these regionsand allows meteorologists to improve their forecasts. Of particular importance is how the TCBL ismodified when abrupt changes in surface terrain conditions occur, such as during landfall, which cansignificantly alter the physical structure of a TC. Although near-surface TC wind data has begun to becaptured through coordinated field campaigns in, for example, the USA and Australia, there is littleexplicit information on how the TCBL is modified during landfall or in the vicinity of other suddenchanges in land surface conditions. This thesis sets out to investigate this process through, 1) analysisof near-surface wind observations, and 2) numerical simulation of idealised TCs.To explore how near-surface turbulence is modified, the present study analysed observational TCwind records at measurement heights of 2.25 m, 3 m, 5 m, and 10 m collected during 11 TCs from theFlorida Coastal Monitoring Program (FCMP), StickNet, and the Surface Weather Information Relayand Logging network (SWIRLnet). These low-level records will be analysed to assess their turbulentcharacteristics and the response of these characteristics to sudden changes in land surface. Resultswere compared with traditional engineering models (AS/NZS1170.2, ESDU) predicting turbulencetransition in non-TC environments to assess their efficacy in TC environments. Results show thatturbulence statistics require about 2 km to reach equilibrium with the underlying terrain, independentof measurement height and upstream terrain. Engineering models tested were found to over predictturbulence intensities in a TC environment. A simple empirical model for estimating the transition ofturbulence intensity following a single change in terrain is proposed.Exploring more broadly how the mean TCBL structure is modified during TC landfall, this thesisalso uses hybrid real-idealised Weather Research and Forecasting (WRF) numerical simulations toinvestigate the mean TCBL response during landfall. This numerical modelling method combines anidealised spun-up TC and a real world environment to undertake a series of parametric simulationswhere idealised TCs impact coastlines with a range of terrain conditions. These tests systematicallyexplore how sudden changes in terrain (e.g. sea to different land surfaces) influence bulk stormcharacteristics (e.g. TC size, radius of maximum wind), surface wind footprints, and vertical TCwind profiles in different parts of simulated TCs. Generated TC wind profiles are also compared withobservational dropsonde data as well as one existing analytical model. Increased surface roughnessover land was found not to deflect the TC track prior to landfall, but was shown to lower TC intensity.Increased surface roughness was also found to reduce maximum surface level wind speeds by up to70\% within 12 hours after TC landfall. Modelled TCBL profiles over water follow a logarithmic windprofile up to the height of maximum wind speed, which increases with TC radius. TCBL profiles overland also exhibit a logarithmic wind profile but wind speeds decay faster particularly closer to thesurface.

}, keywords = {building resilience, cyclones, Emergency management, severe storms, Simulation modelling, strong winds}, author = {Thomas Kloetzke} }