@article {bnh-3957, title = {Development of a full-scale structural testing program to evaluate the resistance of Australian houses to wind loads}, journal = {Frontiers in Built Environment}, year = {2017}, month = {04/2017}, abstract = {

Extensive damage to houses during severe tropical cyclones in the 1970s in Australia highlighted the need for research-based structural engineering principles to be applied in design and construction of houses. Houses have structural redundancies and complex load paths, so the analysis of even simple houses was complicated. In order to evaluate the structural performance of these parallel systems, full-scale house testing commenced at the Cyclone Testing Station (CTS) in the early 1980s with the static multipoint loading of an old house destined for demolition. Following that test program, nine full-scale houses were tested under static and cyclic loading to evaluate load paths in different types of houses with different building practices and materials. Results have been incorporated into amendments of house construction codes, standards, and manuals. Advances in computer modeling and instrumentation have led to more sophisticated full-scale studies. Data on real houses under construction have informed this work and enabled analytical models to incorporate variability in strength of connections in a way that a single test cannot. Progressive failure in the structural systems of timber-framed housing can now be studied to differentiate between houses that have significant damage and seemingly identical ones that have limited damage in the same wind event. These studies involve wind tunnel investigations to determine temporal pressure distributions; full-scale multiple tests on connections (with and without construction defects) to determine statistical distributions of strength and load/deflection relationships; and full-scale tests on houses or portions of houses to determine load sharing mechanisms between parallel structural and non-structural elements. The results of the test programs were used to calibrate the analytical models, which can be used for reliability studies. The paper presents a summary of the methodology and findings from previous CTS full-scale house tests. The results of the most recent research using full-scale tests on a portion of a house and its companion numerical models are discussed and the benefits and limitations of the process outlined.

}, doi = {10.3389/fbuil.2017.00021}, url = {http://journal.frontiersin.org/article/10.3389/fbuil.2017.00021/full}, author = {Boughton, Geoffrey N. and Korah Parackal and Satheeskumar, N and David Henderson} } @article {bnh-3434, title = {Wind uplift strength capacity variation in roof-to-wall connections of timber-framed houses}, journal = {Journal of Architectural Engineering}, volume = {22}, year = {2016}, month = {02/2016}, abstract = {

The roof-to-wall connection in a house is designed to transfer the uplift and lateral loads during strong winds by providing a continuous load path from the roof to the foundation. The uplift capacity and failure mode of the connection depends on the number and type of fasteners (nails), timber species, type of framing anchor, and constructions defects. This paper presents experimental results that were used to assess the uplift capacity variation of typical roof-to-wall connections. Based on tests with two types of connections (triple grip and truss grip) assembled with two types of timber (radiata pine and spruce pine), nails (hand and gun), and framing anchors (triple grip and universal triple grip), the results show that the variation in timber species, nail, and triple grip type changes the strength and the failure modes of the connection. The strength of the connection was reduced by about 24\% when the timber species was changed from radiata pine to spruce pine and the hand nail to gun nail on the triple grip connection. This study also showed that construction defects in roof-to-wall connections influence the design uplift capacity. If there are two missing nails in the hand-nailed triple grip connection (i.e., one nail on the truss and another one on the top plate) the design uplift capacity reduces by about 40\% of the ideal hand-nailed triple grip connection. This study identified the critical nails and their locations required to mitigate failure of the roof-to-wall triple grip connection subject to wind loading.

}, doi = {10.1061/(ASCE)AE.1943-5568.0000204$\#$sthash.bMSTwFiH.dpuf}, url = {http://ascelibrary.org/doi/10.1061/\%28ASCE\%29AE.1943-5568.0000204}, author = {Satheeskumar, N and David Henderson and John Ginger and Wang, CH} }