Architectural, Engineering and Construction (AEC) projects are becoming more complex in terms of client requirements, stakeholder issues, physical, budget and time constraints, and safety and environmental concerns. These constraints have spawned ad-hoc innovations in some AEC projects, without structured frameworks for their assessment, resulting in varying success for these innovations. The primary goal of the thesis is to test an existing framework for evaluating innovative design and construction technologies for high-rise buildings by way of a case-study. The case study is a48-story structure (with an 8-level sub-grade parkade) in a downtown setting with significant constraints and challenges. Unlike most other assessment frameworks which are single-issue based (financial, cost, time or risk), a holistic method that captures a broad range of critical issues at the micro and macro levels is used to screen a number of construction innovations. The process highlights the primary difficulty in balancing stakeholder issues, technical/engineering requirements and project goals in assessing the overall feasibility and net benefits of an innovation. As a useful tool, it facilitates the engineering/technical judgment of proposed innovations and provides evidence of a sufficient trade-off between incremental 'cost and benefits' to justify a detailed evaluation and possible subsequent use of a subset of the innovations that passed successfully through a tiered first stage evaluation process. A secondary objective is to propose appropriate quantitative models for a detailed evaluation of the screened technologies that not only seeks to quantify incremental cost and benefits (e.g. time, increased revenue, etc.) but also assess the level of certainty (in benefits and cost) of innovative construction technologies. An illustrative evaluation provides insights as to the level of modeling and analysis required to evaluate an innovative or novel strategy both at the 'activity/work package' and project levels. The quantum of data required at the pre-construction planning stage coupled with the lack of easy to apply evaluation models probably accounts for the non-prevalence of detailed quantitative evaluation of innovative construction technologies on AEC projects, especially in terms of impact at the project level and the degree of certainty with which net benefits are likely to be achieved.

A new damping technology, the Viscoelastic Coupling Damper (VCD), has been developed at the University of Toronto for reinforced concrete (RC) coupled wall high-rise buildings. These dampers are introduced in place of coupling beams to provide distributed supplemental damping in all lateral modes of vibration. This thesis presents an analytical investigation of the application of VCDs in a high-rise case study building located in a region of high seismicity. A parametric study has been conducted to determine the optimal number and placement of the dampers to achieve enhanced seismic performance without compromising the wind response of the structure. Nonlinear time history analyses have been carried out in order to compare the seismic performance of a conventional coupled wall building to alternative designs incorporating VCDs. Results highlight the improved performance of VCDs over RC coupling beams at all levels of seismic hazard. A design procedure for seismic-critical buildings is proposed.

A large portion of the existing building stock in North America is comprised of post-World War II high-rise apartment buildings, particularly in the Greater Golden Horseshoe in Ontario. They are home to a large portion of the Canadian population. These buildings are nearly 50 years old and reaching the end of their useful lifespan. Significant deterioration has lead to life safety concerns, poor standards of living, and aesthetic degradation. They also consume a significant amount of energy resulting in contributing to Canada’s high per capita greenhouse gas emissions. This thesis investigates the impact of various retrofit strategies on the energy consumption, durability, and occupant comfort of the towers. The building enclosure is the primary focus. The impacts were analyzed using three approaches. Whole building energy consumption was simulated by adapting a spreadsheet based Building Energy and Loads Analysis (BELA) model, originally intended for office buildings. Heat flow and temperatures across the enclosures were modeled using a two-dimensional finite element model (Therm 5.2). A single, theoretical building dubbed the, “Archetype”, was developed to define the characteristics of a “typical” tower using details extracted from four sets of drawings for towers built in Toronto during the late 1960s. Various quantities and configurations of thermal insulation were added to the Archetype and the resulting effective thermal resistances were modeled. Adding insulation to the interior significantly reduces the effectiveness of any added thermal resistance. Insulating on the exterior allows the insulation around the balconies to reach 80% of its rated value, even without insulating the balconies. Energy efficiency measures (EEMs) including retrofitting the walls, windows, appliances, or HVAC equipment were simulated and it was found that each on its own did not have a major impact on annual energy consumption. Packages of EEMs were created and simulated. It was found that a basic and high-performance whole building retrofit packages would save approximately 40% and 55% of the annual energy consumption, respectively, based on the Archetype. An analysis and discussion of the enclosure retrofit impacts on freeze-thaw potential, interior surface and interstitial condensation, occupants’ thermal comfort, and passive thermal comfort was completed. An interior versus exterior enclosure retrofit comparison summary illustrated that an exterior enclosure retrofit has significant benefits relative to an interior retrofit including ease of construction, greater durability, and improved comfort. The difference in annual energy reduction between an interior and exterior enclosure retrofit was small.

Thesis (M.S.W.)--University of Hong Kong, 1983.

Thesis (M. Soc. Sc.)--University of Hong Kong, 1984.

published_or_final_version / Architecture / Master / Master of Philosophy

published_or_final_version / Housing Management / Master / Master of Housing Management

published_or_final_version / Housing Management / Master / Master of Housing Management

The effects that thermally induced forces and deformations have on the performance and safety of steel columns subjected to fire are not well understood and are not clearly treated in building codes and standards. This thesis investigates the behavior of steel columns subjected to fire, with an emphasis on studying the significance of thermally induced forces and deformations. The approach used in this research is to conduct a series of analyses of steel columns using the finite element computer program ABAQUS. Columns are modeled in ABAQUS using beam elements that include nonlinear geometry, nonlinear temperature dependent material properties, and initial geometric imperfections. Using the ABAQUS model, a series of analyses are conducted on the behavior of columns under axial compression for temperatures varying from room temperature up to 2400° F. A series of individual columns are analyzed with and without restraint to thermal expansion. A column that is part of a truss is also analyzed to study a simple case of a flexible restraint to thermal expansion. Finally, the behavior of columns that are part of multi-story steel moment frames are investigated. All of the analyses conducted in this research indicate that forces generated by restraint to thermal expansion can have a very large impact on the performance of a steel column in fire. When evaluating the safety of a column in a fire, it is important to recognize that the total axial force in the column is the sum of the force generated by external gravity load on the frame and the force generated by restraint to thermal expansion. The force generated by restrained thermal expansion can be very large, and neglecting this force can lead to unsafe designs. / text

published_or_final_version / Housing Management / Master / Master of Housing Management