In the last decade, Australian civil engineers have not paid enough attention to earthquake resistant design of structures. It was commonly believed that the earthquake risk was insignificant thus earthquake resistant design was not considered for most buildings. Earthquake resistant design of structures has become an important issue in Australia following the Newcastle earthquake in 1989. / Masonry is one of the most commonly used materials throughout Australia for the construction of low rise buildings. Even though the history of past earthquakes has shown that masonry buildings suffered the maximum damage and accounted for the maximum loss of life, they continue to be popular. It was evident from the Newcastle earthquake that most unreinforced masonry structures were seriously damaged. Therefore it is important to retrofit and strengthen existing masonry structures to resist the potential earthquake damages. / For the last twenty years, several seismic retrofitting techniques for masonry structures have been developed and practiced, but rarely validated with experiments and numerical modelling. Further more, the research has been carried out mainly in America and Japan where the risk of major earthquake is high. In Australia, although unreinforced masonry is one of the most popular types of construction, research into seismic retrofitting of masonry structures is rare. / The purpose of this research is to develop a new, cheaper and high strength seismic retrofitting technique for masonry structures. An innovative retrofitting technique is presented for improving the seismic resistance of unreinforced masonry walls using cable systems. In this thesis, the experimental results from four unreinforced masonry walls and eight unreinforced masonry walls retrofitted with cable systems are presented. Seven unreinforced masonry walls retrofitted with FRP were also conducted in this research for comparison purpose. All walls were tested under combined constant gravity load and incrementally increasing in-plane lateral displacement reversals. The results showed that both the strength and ductility of tested specimens were significantly enhanced with this new technique. Seismic retrofitting of unreinforced masonry walls with cables proved to be an effective and reliable strengthening alternative. / In this thesis, a basic mechanical model has been introduced first using the simple truss model. Then, two nonlinear finite element models based on this basic mechanical model have been developed to validate the experimental results. One model is developed for unreinforced masonry walls retrofitted by cable system and the other model is developed for unreinforced masonry walls retrofitted by FRP. All of the models have been found between the analytical and experimental results are reasonably good agreement. The model takes into account the material nonlinearities as well as damage due to progressive cracking. Behaviour of the masonry is modelled using the theory of plasticity and cracking is modelled using smear cracking approach. The model is generated using ABAQUS Finite Element program. The validity of the model is established by comparison with the experimental results. It is shown that both of the numerical models are capable of predicting not only the load carrying capacity, but also the failure mode and, ductility of the retrofitted masonry walls. / This thesis reviews the literature on all seismic retrofitting techniques and compares their advantages and disadvantages to identify the most effective and economic retrofitting method for unreinforced masonry buildings. It also presents the basic concepts of seismic retrofitting and summarizes the findings from recent experimental and analytical research activities on the seismic retrofitting of unreinforced masonry buildings and provides some retrofit strategies on the most common failure modes. It is expected that this thesis will provide some guidelines to assist Australian engineers to retrofit unreinforced masonry buildings. / Thesis (PhD)--University of South Australia, 2005.
| Identifer | oai:union.ndltd.org:ADTP/267412 |
| Creators | Chuang, Shih-Wei. |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
| Rights | copyright under review |
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