@article {bnh-7017, title = {Axial Load Variation of Columns in Symmetrical RC Buildings Subject to Bidirectional Lateral Actions in Regions of Low to Moderate Seismicity}, journal = {Journal of Earthquake Engineering}, year = {2020}, month = {06/2020}, pages = {1-29}, abstract = {

Columns in building frame systems are subjected to the combined action of bidirectional horizontal loading and axial load variation during an earthquake. Whilst the behaviour of RC columns under unidirectional and bidirectional lateral loading with constant axial load is understood well, the behaviour under bidirectional lateral loading with axial load variation is rarely studied, especially for limited ductile RC columns prevalent in regions of low to moderate seismicity. This paper begins with a numerical study that aims to obtain the generalised patterns and range of axial load variation in RC building columns. To this end, a case study building is subjected to a suite of 15 ground motions, representative of low to moderate seismic regions, in OpenSees. This is followed by an experimental study in which limited ductile high-strength RC columns are tested under bidirectional lateral loading and two different axial load variation protocols, namely synchronous and nonsynchronous variable axial loading protocols. The results of the numerical study demonstrated that axial load variation of the columns in an RC building is primarily dependent on the response spectral acceleration corresponding to the fundamental period of the structure in the two orthogonal horizontal directions and/or the vertical direction. The results of the experimental testing showed that nonsynchronous axial loading (compared to constant and synchronous axial loading) results in the lowest collapse drift capacity and energy dissipation of the RC columns.

}, keywords = {Axial load variation, bidirectional loading, drift capacity, earthquake, RC columns}, doi = {https://doi.org/10.1080/13632469.2020.1772151}, url = {https://www.tandfonline.com/doi/abs/10.1080/13632469.2020.1772151?journalCode=ueqe20}, author = {Saim Raza and Scott Menegon and Hing-Ho Tsang and John Wilson} } @article {bnh-7464, title = {Collapse probability of soft-storey building in Australia and implications for risk-based seismic design}, journal = {Australian Journal of Structural Engineering}, year = {2020}, month = {10/2020}, pages = {1-13}, abstract = {

Collapse prevention is the primary objective of earthquake-resistant design of structures; hence, the probability of collapse should be taken as a crucial performance indicator for risk-based design of new structures or assessment of existing structures. One major challenge in collapse risk assessment is to reliably model the non-linear structural response behaviour. This study features the rocking response behaviour of precast reinforced concrete (RC) columns based on results from previous field testing on parts of a real building and supplemented with a study of their rocking behaviours through a series of shake-table tests. The effects of bidirectional earthquake actions on failure drift capacity of columns have also been incorporated, such that realistic estimates of displacement capacity were made for constructing collapse fragility functions, which were then combined with the ground motion recurrence relationships of Melbourne, Australia for the computation of collapse probability. A suite of typical soft-storey buildings was adopted, with considerations given to a diversity of site conditions. Deaggregation of the results reveals the range of return periods that controls the collapse risk, which could have important implications for the choice of earthquake scenarios for seismic analysis and design in regions of lower seismicity.

}, keywords = {Collapse Probability, drift capacity, Return Period, Risk-based Seismic Design, soft-storey building}, doi = {https://doi.org/10.1080/13287982.2020.1835157}, url = {https://www.tandfonline.com/doi/abs/10.1080/13287982.2020.1835157}, author = {Hing-Ho Tsang and John Wilson and Emad F Gad} }