@article {bnh-6885, title = {Progressive failures of batten to rafter connections under fluctuating wind loads}, journal = {Engineering Structures}, volume = {215}, year = {2020}, month = {05/2020}, abstract = {

Batten to rafter connections in light framed timber housing can be vulnerable to wind loading, and failures of these connections are one of the more common failure modes seen in post windstorm damage surveys. Such failures often occur in a progressive or cascading manner resulting in the loss of a large section of the roof envelope. These progressive failures of batten to rafter connections are a complex process influenced by the pressure fluctuations on the roof surface, the response of individual connections and the behaviour of the structural system as a whole. This study presents a method for examining load redistribution and progressive failure behaviour of batten to rafter connections in light framed structures. Nonlinear time history analyses were performed using a finite element model using fluctuating pressures determined from a wind tunnel study and connection properties determined from laboratory testing of connections under dynamic loads.

}, keywords = {Light framed structures, Low-rise buildings, progressive failures, wind loads}, doi = {https://doi.org/10.1016/j.engstruct.2020.110684}, url = {https://www.sciencedirect.com/science/article/abs/pii/S0141029619346395}, author = {Korah Parackal and John Ginger and David Henderson} } @mastersthesis {bnh-6714, title = {The structural response and progressive failure of batten to rafter connections under wind loads}, year = {2018}, month = {12/2018}, school = {James Cook University}, address = {Brisbane}, abstract = {

Batten to rafter connections in light framed timber housing are vulnerable to wind\ loading and failures of these connections are one of the more common failure modes\ seen in post windstorm damage surveys. Such failures often occur in a progressive or\ cascading manner resulting in the loss of a large section of the building envelope.\ These progressive failures of batten to rafter connections are a complex process\ influenced by the pressure fluctuations on the roof surface, the response of individual\ connections and the behaviour of the structural system as a whole.

This study presents a method of examining load redistribution and progressive failure\ behaviour of batten to rafter connections in light framed structures. Nonlinear time\ history analysis was performed using a finite element model using fluctuating\ pressures determined from a wind tunnel study and connection properties determined\ from laboratory testing of connections under dynamic loads.

Flow separation and building-induced turbulence cause intermittent {\textquoteleft}peak-events{\textquoteright}\ where negative pressures on the roof surface are especially high. These {\textquoteright}peak-events{\textquoteright}\ can move across the roof causing high loads occurring at different connections with\ slight lead or lag times. Damage to connections occur during the {\textquoteright}peak events{\textquoteright} as nails\ are incrementally withdrawn. Loads are redistributed and load paths change during\ nail slips, causing damage to spread from an initial location. Load redistribution\ continues until a few connections fail completely, upon which a cascading failure\ occurs where almost all connections on the roof fail in rapid succession.

As an application of this research, the analyses performed were used to assess the fragility of batten-rafter failures, and the most vulnerable parts of the roof identified. Cost effective retrofitting measures can be justified and designed with this\ information.

}, keywords = {batten to rafter, Correlation of loads, Light framed structures, Low-rise buildings, progressive failures, wind engineering, wind loads, Wind tunnel study}, url = {https://researchonline.jcu.edu.au/62277/}, author = {Korah Parackal} } @article {bnh-4467, title = {Wind load fluctuations on roof batten to rafter/truss connections}, journal = {Journal of Wind Engineering \& Industrial Aerodynamics}, volume = {175}, year = {2018}, month = {02/2018}, abstract = {

Batten to rafter connections in light framed housing can be vulnerable to progressive or cascading failures where a localised failure can cause the loss of a large section of the roof envelope. The synchrony of loads at neighbouring connections may affect the initiation of such failures. A 1/50 length scale wind tunnel model study was performed on a gable roof house to record spatial and temporal pressure fluctuations on the roof surface and data were studied to determine the flow separation mechanisms causing different loading patterns on batten to rafter connections. The cross correlation between load time histories was used to give a measure of synchrony between loads experienced at neighbouring connections and indicate the direction that fluctuations move across the roof. Orthogonal wind directions result in 2-dimensional flow separation that produce more synchronous loads at batten to rafter connections than cornering wind directions, where conical vortices produce high uplift forces on connections. The patterns of loading and their correlations give a means of identifying which parts of the roof and which approach wind directions may result in the initiation of a progressive failure of batten to rafter connections.

}, keywords = {Correlation of loads, Light framed structures, Low-rise buildings, Progressive failures., Wind tunnel study}, doi = {https://doi.org/10.1016/j.jweia.2018.01.032}, url = {https://www.sciencedirect.com/science/article/pii/S0167610517304506}, author = {Korah Parackal and John Ginger and David Henderson} }