@article {bnh-7481, title = {In-plane response of perforated unreinforced masonry walls under cyclic loading}, journal = {Journal of Structural Engineering}, volume = {146}, year = {2020}, month = {06/2020}, abstract = {

This paper presents the results of an experimental study into the behavior of perforated (containing openings) unreinforced masonry (URM) walls subjected to cyclic in-plane lateral loading. Damage to perforated URM walls during previous earthquakes has revealed that the in-plane response is mainly influenced by the pier and spandrel geometry, as well as the level of axial compressive stress on the walls due to gravity loading. The study focused on masonry typologies representative of historical URM buildings in the Australian context. To investigate this behavior, eight full-scale URM walls with semicircular arched openings, double wythe thickness, and materials representing masonry construction from the mid-19th to mid-20th century were constructed for pseudostatic cyclic in-plane testing. The experimental program considered varying spandrel depths and pier widths and the imposed vertical loading on the piers was also varied to observe the lateral load capacity and the variation of pier-spandrel failure modes. The test results showed that the in-plane capacity and the failure modes were significantly affected by changes of wall geometry and the imposed vertical precompression loading. Predictions of wall strengths, in-plane stiffnesses, and failure modes according to ASCE guidelines show that the guidelines agree well with the test observations.

}, keywords = {earthquake, lateral loading, unreinforced masonry}, doi = {https://doi.org/10.1061/(ASCE)ST.1943-541X.0002657}, url = {https://ascelibrary.org/doi/full/10.1061/\%28ASCE\%29ST.1943-541X.0002657}, author = {Milon Howlader and Mark Masia and Michael Griffith} } @article {bnh-7482, title = {In-plane shear testing of unreinforced masonry walls and comparison with FEA and NZSEE predictions}, volume = {5}, year = {2020}, month = {01/2020}, abstract = {

The present study was conducted to investigate the global and local in-plane response of perforated URM walls under earthquake loading, based on observations of damage from previous earthquakes. To do so, full-scale cyclic in-plane testing of URM walls with an arched opening which were designed to represent walls in heritage URM structures in Australia was performed. The study investigated the behaviour of both pier and spandrel elements within the walls. Emphasis was also given to the position of walls within a multi-storey building by varying the pre-compression loads (representing gravity loads) on the walls. The tested walls were then simulated using nonlinear finite element analyses (FEA) where simplified micro-modelling (crack-shear-crush) approaches were used to analyse the wall behaviour. Finally, the shear capacities and the failure modes of the walls obtained from the experimental tests and FE analyses were compared to the proposed New Zealand Society for Earthquake Engineering (NZSEE) predictions.

}, keywords = {cyclic testing, FEA, finite element analyses, in-plane shear behaviour, NZSEE, unreinforced masonry, URM}, doi = {https://doi.org/10.1504/IJMRI.2020.104845}, url = {https://www.inderscienceonline.com/doi/abs/10.1504/IJMRI.2020.104845}, author = {Milon Howlader and Mark Masia and Michael Griffith} } @article {bnh-7483, title = {Numerical analysis and parametric study of unreinforced masonry walls with arch openings under lateral in-plane loading}, journal = {Engineering Structures}, volume = {208}, year = {2020}, month = {04/2020}, abstract = {

This paper presents numerical modelling of the in-plane shear behaviour of unreinforced masonry (URM) walls with a semicircular arch opening. To do so, two dimensional finite element (FE) modelling of a series of experimentally tested walls was conducted using the simplified micro-modelling approach. The models successfully captured the load-displacement behaviour and, to a large extent, the failure modes of the piers and spandrels observed in the experimentally tested walls. The exception was that the FE modelling did not show pier diagonal shear cracking which was observed in some of the tested walls. The model was then used to perform parametric studies to investigate the effect of geometric variations of the walls as well as the effect of vertical pre-compression stresses on the lateral in-plane capacity of the walls. The results obtained from the FE analyses were compared to the anticipated maximum shear strength and the predicted failure modes according to the New Zealand Society for Earthquake Engineering (NZSEE, 2017). From this study, it is shown that there is a significant effect of the wall geometry and vertical pre-compression load on the failure modes and the lateral load resistance capacity of the walls. In most of the cases investigated, the NZSEE equations for maximum shear strength and failure modes agree well with the FEM results. The arch opening was remodelled to a rectangular opening and it was found that the effective pier height for an equivalent rectangular pier adjacent to a semi-circular arched opening can be taken up to the half height of the arch radius.

}, keywords = {Unreinforced masonryIn-plane lateral loadingFEMAspect ratioPre-compression loadWall openingsPiersSpandrels}, doi = {https://doi.org/10.1016/j.engstruct.2020.110337}, url = {https://www.sciencedirect.com/science/article/abs/pii/S0141029619336867}, author = {Milon Howlader and Mark Masia and Michael Griffith} }