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Dixon C.R.,University of Florida | Masters F.J.,University of Florida | Prevatt D.O.,University of Florida | Gurley K.R.,University of Florida | And 3 more authors.
Journal of Wind Engineering and Industrial Aerodynamics | Year: 2014

This paper addresses the wind-induced tearing and blow-off of asphalt roofing shingles, which are the most frequently observed forms of residential building damage in hurricanes. Field surveys indicate that in-service asphalt shingle sealant strips can lose adhesion along their leading edge over time, leaving the shingle partially unsealed and susceptible to wind uplift. Two interrelated studies presented in this paper show that unsealing is a naturally occurring process and that unsealed shingles are a contributing cause of shingle roof cover damage in high winds. The first study quantified the number, location, and failure mode of laminate and three-tab style shingle systems installed on residential buildings at 30 sites in Florida and Texas. Systematic patterns of partially unsealed field shingles found on 22 of the 30 roofs resembled spatial patterns of wind-induced shingle damage observed in post-hurricane building performance assessments. As expected, older roofs generally contained more unsealed shingles than newer roofs. The results of the second study link blow-off to partially unsealed shingles. Seventeen ASTM D7158 Class H asphalt shingle roofs were aged outside for nominally one year at the Insurance Institute for Business & Home Safety Research Center and then evaluated in full-scale wind tunnel tests. Partially unsealed field and hip shingles frequently exhibited damage during wind testing, while fully sealed shingles were not damaged unless adjacent, unsealed shingles failed first. © 2014. Source

Bahrani B.,University of North Carolina at Charlotte | Zhou A.,University of North Carolina at Charlotte | Quarles S.L.,Insurance Institute for Business and Home Safety
International SAMPE Technical Conference | Year: 2016

Fire retardant coatings have been an important part of passive fire protection system for protecting structures in wildland urban interface (WUI) fires. However, limited studies have been conducted on their effectiveness and performance after long-term weathering exposure. This paper presents a study on the effects of weathering on the performance of intumescent fire-retardant coatings on wooden structures in the WUI. The main concerns of weathering effects are: 1) the reduction of ignition resistance of the coating layer after weathering; and 2) the fire properties of coatings after weathering as the coatings might contribute as a combustible fuel and assist the fire growth after ignition. The study evaluated three intumescent coatings which exposed to natural weathering conditions in three time intervals. More than 190 combustibility tests consisted of a bench-scale performance evaluation using a cone calorimeter were performed, and three radiative heat flux levels were used for each coating type and weathering period. The key findings for each coating type under different test conditions are discussed, and the performance evaluation criteria for the combustibility tests is presented. Copyright 2016. Used by the Society of the Advancement of Material and Process Engineering with permission. Source

Henderson D.J.,University of Western Ontario | Henderson D.J.,James Cook University | Morrison M.J.,University of Western Ontario | Morrison M.J.,Insurance Institute for Business and Home Safety | Kopp G.A.,University of Western Ontario
Engineering Structures | Year: 2013

A full-scale, timber-framed, truss, hip roof was subjected to simulated wind loads. Spatially and temporally varying pressures were applied using an array of 58 Pressure Loading Actuators, together with air-boxes covering all roof surfaces. Load cells were incorporated at the top of the wall frame, just below the top plate, to measure the reactions at the toe-nailed roof-to-wall connections. Changes in influence functions and load sharing between adjacent trusses were observed to occur during withdrawal (slip) of the toe-nail connections caused by large magnitude, short duration peak pressures. Even for relatively small displacements, it was observed that the effective tributary area is substantially increased by the incremental withdrawals. This acts to increase the resilience of the roof by allowing more limber and/or more highly loaded connections to transfer loads to stiffer and/or less highly loaded connections. Influence functions, measured both prior to and following damage, were able to predict this behaviour. © 2013 Elsevier Ltd. Source

Heymsfield A.J.,U.S. National Center for Atmospheric Research | Giammanco I.M.,Insurance Institute for Business and Home Safety | Wright R.,Robert L. Wright and Assoc. Inc.
Geophysical Research Letters | Year: 2014

The physical properties of 2295 hailstones that developed in Great Plains (US) storms were measured, including their maximum dimension, mass, and cross-sectional area. Using these data, size-dependent relationships for their terminal velocities and kinetic energies are developed. These relationships can be used in weather forecast modeling and hail damage prediction and assessment. When hailstones are assumed to be spherical, their terminal velocities and kinetic energies are in agreement with what has been reported in previous studies. When non-sphericity is considered, which is the case for natural hail, the terminal velocities and kinetic energies are, on average, lower than those of spheres of the same maximum diameter, but can be larger. © 2014. American Geophysical Union. All Rights Reserved. Source

Giammanco I.M.,Insurance Institute for Business and Home Safety | Schroeder J.L.,Texas Tech University
12th Americas Conference on Wind Engineering 2013, ACWE 2013: Wind Effects on Structures, Communities, and Energy Generation | Year: 2013

The development and deployment of Texas Tech University's StickNet adaptive observing network has yielded an increased number of observations from the immediate shoreline [1]. The current study leverages research grade wind measurements from 6 different landfalling tropical cyclones from 2008-2012. Twenty-four individual deployments were made along the immediate shoreline resulting in over 1500 ten-minute data segments from onshore marine exposure regimes. The number of available data segments allowed for the wind flow characteristics to be examined as well as their dependence upon changing mean wind speed. Gust factors were found to be quite similar to overland open and smooth terrain exposures while roughness lengths and drag coefficient values approached those observed in deep water conditions [2][3]. Source

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