- Title
- In-plane behaviour of unreinforced masonry (URM) walls with openings in Australian heritage construction
- Creator
- Howlader, Milon Kanti
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2020
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- The research reported in this thesis focused on seismic assessment of perforated (that is, containing door and/or window openings) unreinforced masonry (URM) walls, representative of those used in heritage URM constructions throughout Australia. The primary aim of the research was to evaluate the performance of the URM walls under quasi-static cyclic in-plane loading to get a deeper understanding of the pier-spandrel response in perforated URM walls. Most of the heritage buildings were constructed before the development of the seismic design guidelines, hence the seismic capacity of those buildings is poorly understood. Furthermore, many such buildings hold a high level of cultural significance and hence there is a high value placed on their preservation. This PhD thesis aims to assess the seismic vulnerability concerning the parameters that affect the in-plane shear behaviour of the URM walls. In doing so, it is hoped that the research will help inform strategies which will be essential to preserve such construction through proper intervention/retrofitting. As a first step in the investigation process, the building stock listed on the State Heritage Register by the Heritage Council of NSW was characterised to get an overview of the history of the constructions. The buildings were categorised according to the URM materials, the number of stories, roof type (shapes and materials), construction year, geographic location and the past and current use for the buildings. The outcomes from the building characterisations were used to select the prototype specimen geometry and construction practice representative of a wide range of heritage listed URM buildings in NSW. Experimental cyclic in-plane testing of eight full-scale perforated URM walls with semi-circular arched openings was conducted to investigate the effect of pier-spandrel geometry and the vertical pre-compression load. In the experimental design phase, two wall geometries were chosen by varying the spandrel depth and two vertical pre-compression loads were considered to represent walls at different heights in a multi-storey building façade. For each combination of test parameters two wall specimens were intended to be tested, resulting in eight wall specimens in total. However, as the testing progressed, the variation of the performance between the two repeat wall tests with shallow spandrel and low pre-compression level was not significant. Hence, the repeat of the deep spandrel wall with low pre-compression load was not conducted and instead, a new geometry with asymmetric pier lengths was introduced resulting in different pre-compression levels in the two piers. The test results showed significant effect of the wall geometry and pre-compression load on the load-displacement behaviour, the failure mode, stiffness degradation and the energy dissipation of the walls. Also, the results showed that for the same configuration of the walls, the failure mode varied between specimens for some combinations of test variables. Finite element (FE) modelling and analysis was carried out using Diana FEA 10.2 (DIANA FEA, 2017). The FE analysis was performed in two phases. In the first phase, the preliminary analysis was done where the material input parameters were taken from previous researchers. The preliminary analyses were used to help design the experimental wall testing program. In the final phase, the tested properties for the materials used to construct the walls were inserted into the FE model. The geometry of the arch portion of the walls was also modified according to the actual test wall construction. The final FE modelling, representing the tested walls, performed well in predicting the experimental load displacement behaviour and the crack patterns. Finally, with the validated nonlinear FE modelling, a parametric study was conducted. The results from the experimental and the FE analyses were compared to the New Zealand Society for Earthquake Engineering (NZSEE) guidelines for predicted maximum lateral strength and probable failure modes, to assess the reliability of the NZSEE provisions.
- Subject
- seismic assessment; heritage buildings; earthquake engineering; construction; wall testing
- Identifier
- http://hdl.handle.net/1959.13/1412118
- Identifier
- uon:36431
- Rights
- Copyright 2020 Milon Kanti Howlader
- Language
- eng
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| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details Download | ATTACHMENT01 | Thesis | 45 MB | Adobe Acrobat PDF | View Details Download | ||
| View Details Download | ATTACHMENT02 | Abstract | 886 KB | Adobe Acrobat PDF | View Details Download |