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A large number of building inventory in Canada and elsewhere in the world consists of non-ductile reinforced concrete frames, with or without masonry infill panels. These structures suffer damage when seismic force demands are higher than their force capacities. Therefore, seismic retrofitting of such frame buildings for drift control remains to be a viable option for improved building performance. A retrofit methodology has been developed in the current research project, which involves diagonal bracing of frames with prestressing strands. An experimental research project has been conducted to assess the effectiveness of diagonal prestressing in non-ductile reinforced concrete frame buildings. The experimental program consists of two large-scale single-bay single-storey reinforced concrete frames, with a height of 3.0m and a span length of 3.5 m. The frames were designed and built to reflect the 1960’s practice in Canada, without the seismic requirements of current building codes, and hence are seismically deficient. They were retrofitted with diagonally placed prestressing strands, having two different areas of steel, prestressed to 40% of the strand capacity. One of the frames was retested after the failure of the strands, with a new set of strands without any prestressing, forming the third test. The results indicate that lateral bracing reinforced concrete frames with high-strength prestressing strands is an effective strategy for controlling lateral drift and hence potential damage in buildings during strong earthquakes. Prestressing of the strands increases initial stiffness, as compared to non-prestressed cables, and provide superior performance. The area of diagonally placed steel (including the number of strands) and the level of initial prestressing depend on the required level of upgrade in the building in terms of seismic force requirements. The design procedure recommended in this thesis may be employed for implementing the technology. The thesis presents the details of the experimental program, and the test results. It also provides analytical verification of the approach, with a step-by-step design procedure.

A number of recent fires in single-storey warehouses have drawn attention to a current lack of understanding about the structural response of industrial portal frame structures to elevated temperatures. This research project has investigated the subject by conducting fire tests on a scaled model and by computer modelling using the non-linear finite element program VULCAN. This program has been developed in-house by the University of Sheffield and is capable of modelling the behaviour of three-dimensional steel and composite frames at elevated temperatures. It has been validated throughout its development. An initial investigation was conducted to validate the program for analysing inclined members, which form part of a pitched- roof portal frame, but for which it was not initially developed. Additional features were implemented into the program where necessary. A series of indicative fire tests was conducted at the Health and Safety Laboratories, Buxton. A scaled portal frame model was designed and built, and three major fire tests were conducted in this structure. In the third of these tests the heated rafters experienced a snap-through failure mechanism, in which fire hinges could clearly be identified. The experimental results were then used for validating the numerical results produced by VULCAN analyses. The correlations were relatively close, both for predictions of displacements and failure temperatures. This gave increased confidence in using VULCAN to conduct a series of parametric studies. The parametric studies included two- and three-dimensional analyses, and a number of parameters were investigated, including the effects of vertical and horizontal load, frame geometry, heating profiles and base rotational stiffness. The influence of secondary members was investigated in the three-dimensional studies using different fire scenarios. A simplified calculation method has been developed for estimating the critical temperatures of portal frames in fire. The results compare well with predictions from VULCAN. The current guidance document for portal frames in boundary conditions has been reviewed, and the concept of performance-based design for portal frame structures has been discussed.

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none / This thesis explores whether hosting the Beijing Olympic Games has helped promote China’s images as measured by quantitative and qualitative analysis of news coverage on China in Time and The Economist. Content analysis showed that coverage on China in both magazines increased as the Beijing Olympic Games neared. Both Time and The Economist paid the most attention to China’s “politics,” “economics,” and “society,” while “education” and “health” received the least coverage. The newsmagazines covered China more negatively than positively; however, Time demonstrated a friendlier stance towards China than The Economist. In terms of length of article, both magazines spent the most number of pages covering “general,” or articles that cover more than one subject, followed by “health” and “economics” in Time and “environment” and “economics” in The Economist. Discourse analysis showed the frames used to cover China in the newsmagazines were, China as a country that suppresses its people’s rights, China as a country full of chances yet beware of risks and uncertainties, China as a country working on environmental protection, China as a country short of resources, the Internet as a medium changing Chinese youth’s way of living, China as an unstable and unequal developing country, China as a country with flowering creativity amid low acceptance, China’s problematic education system yet willing to make changes, China lags in healthcare, disease surveillance and control. Manheim and Albritton (1994) argue that a nation’s image is boosted when positive coverage increases, while negative coverage decreases. This study found that hosting the Olympic Games helped promote China’s images in Time more significantly than in The Economist, particularly in “economics,” “environment,” “technology,” and “culture and leisure”.

Reinforced concrete structures are usually vulnerable to collapse in areas where the earthquakes are frequent. Although plenty of research has been carried out in that regard the problem is still in place. Furthermore, there are buildings that did not collapse with the first and second earthquake but with the third one. That happens because many buildings are generally declared safe after being thoroughly inspected in the visible areas only, ignoring the extent of the damage in the column-to-foundation connections. The criterion of identifying the failure at the base of the columns of the ground floor is that after the earthquake there are no traces of failure. In other words, the cracks at the base of the columns have been healed and concealed the damage in the core of the columns. / Thesis (PhDCivilEngineering)--University of South Australia, 2005.

Thesis (M.S.)--West Virginia University, 2007. / Title from document title page. Document formatted into pages; contains vi, 104 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 100-104).

Thesis (Ph. D.)--University of Hong Kong, 2009. / Includes bibliographical references (p. 196-214). Also available in print.