Unreinforced masonry construction is considered to be the most vulnerable forms of construction as demonstrated through recent earthquakes. In Canada, many densely populated cities such as (Vancouver, Montreal and Ottawa) have large inventories of seismically vulnerable masonry structures. Although measures have been taken to rehabilitate and increase the seismic resistance of important and historic structures, many existing unreinforced masonry structures have not been retrofitted and remain at risk in the event of a large magnitude earthquake. There is therefore a need to identify buildings at risk and develop tools for assessing the seismic vulnerability of existing unreinforced masonry structures in Canada. This thesis presents results from an ongoing research program which forms part of a multi-disciplinary effort between the University of Ottawa’s Hazard Mitigation and Disaster Management Research Centre and the Geological Survey of Canada (NRCAN) to assess the seismic vulnerability of buildings in dense urban areas such as Ottawa, Ontario. A risk-based seismic assessment tool (CanRisk) has been developed to assess the seismic vulnerability of existing unreinforced masonry and reinforced concrete structures. The seismic risk assessment tool exploits the use of fuzzy logic, a soft computing technique, to capture the vagueness and uncertainty within the evaluation of the performance of a given building. In order to conduct seismic risk assessments, a general building inventory and its spatial distribution and variability is required for earthquake loss estimations. The Urban Rapid Assessment Tool (Urban RAT) is designed for the rapid collection of building data in urban centres. This Geographic Information System (GIS) based assessment tool allows for intense data collection and revolutionizes the traditional sidewalk survey approach for collecting building data. The application of CanRisk and the Urban RAT tool to the City of Ottawa is discussed in the following thesis. Data collection of over 13,000 buildings has been obtained including the seismic risk assessment of 1,465 unreinforced masonry buildings. A case study of selected URM buildings located in the City of Ottawa was conducted using CanRisk. Data obtained from the 2011 Christchurch Earthquake in New Zealand was utilized for verification of the tool.

The self-centering energy dissipative (SCED) brace is an innovative cross-bracing system that eliminates residual building deformations after seismic events and prevents the progressive drifting that other inelastic systems are prone to experience under long-duration ground motions. This research improves upon the design and use of SCED braces through three large-scale experimental studies and an associated numerical building model study. The first experimental study increased the strength capacity of SCED braces and refined the design procedure through the design and testing of a new high-capacity full-scale SCED brace. This brace exhibited full self-centering behaviour and did not show significant degradation of response after multiple earthquake loadings. The second experimental study extended the elongation capacity of SCED braces through the design and testing of a new telescoping SCED (T-SCED) brace that provided self-centering behaviour over a deformation range that was two times the range that was achieved by the original SCED bracing system. It exhibited full self-centering in a single storey full-scale frame that was laterally deformed to 4% of its storey height. The third experimental study confirmed the dynamic behaviour of a multi-storey SCED-frame in different seismic environments and confirmed the ability of computer models of differing complexity to accurately predict the seismic response. To achieve these goals, a three-storey SCED-braced frame was designed, constructed, and tested on a shake table. Lastly, a numerical six-storey SCED-braced building model was constructed. This model used realistic brace properties that were determined using a new software tool that simulates the full detailed mechanics of SCED and T-SCED braces. The building model showed that initial SCED brace stiffness does not have a significant effect on SCED frame behaviour, that T-SCEDs generally perform better than traditional SCEDs, and that the addition of viscous dampers in parallel with SCED braces can significantly reduce drifts and accelerations while only causing a small increase in the base shear.

The self-centering energy dissipative (SCED) brace is an innovative cross-bracing system that eliminates residual building deformations after seismic events and prevents the progressive drifting that other inelastic systems are prone to experience under long-duration ground motions. This research improves upon the design and use of SCED braces through three large-scale experimental studies and an associated numerical building model study. The first experimental study increased the strength capacity of SCED braces and refined the design procedure through the design and testing of a new high-capacity full-scale SCED brace. This brace exhibited full self-centering behaviour and did not show significant degradation of response after multiple earthquake loadings. The second experimental study extended the elongation capacity of SCED braces through the design and testing of a new telescoping SCED (T-SCED) brace that provided self-centering behaviour over a deformation range that was two times the range that was achieved by the original SCED bracing system. It exhibited full self-centering in a single storey full-scale frame that was laterally deformed to 4% of its storey height. The third experimental study confirmed the dynamic behaviour of a multi-storey SCED-frame in different seismic environments and confirmed the ability of computer models of differing complexity to accurately predict the seismic response. To achieve these goals, a three-storey SCED-braced frame was designed, constructed, and tested on a shake table. Lastly, a numerical six-storey SCED-braced building model was constructed. This model used realistic brace properties that were determined using a new software tool that simulates the full detailed mechanics of SCED and T-SCED braces. The building model showed that initial SCED brace stiffness does not have a significant effect on SCED frame behaviour, that T-SCEDs generally perform better than traditional SCEDs, and that the addition of viscous dampers in parallel with SCED braces can significantly reduce drifts and accelerations while only causing a small increase in the base shear.

This thesis presents a probability model to predict the maximum rotation of rocking bodies exposed to seismic excitations given specific earthquake intensity measures. After obtaining the nonlinear equations of motion and clarification of the boundaries applied to a rocking body to avoid sliding, a complete discussion is provided on the estimation of approximate period and equivalent damping ratio for the rocking motion. Thereafter, instead of using an iterative solution, which was previously proven defective, a new approximate technique is developed by finding the best representative ground motion intensities. Suitable transformation and normalization are applied to these intensities, and the Bayesian Updating approach is employed to construct a probability model. The proposed probability model is capable of accurately predicting the maximum rotation of a symmetric rocking block given displacement design spectra, peak ground acceleration, peak ground velocity, and arias intensity of an earthquake. This probabilistic model along with the approximate capacity of rocking blocks are used to estimate the fragility curves for rocking blocks with specific geometrical parameters. At the end, a comprehensive and practical form of fragility curves and numerical examples are provided for design purposes.

The primary loading on wind turbines is in the lateral direction and is of a stochastic nature, due to wind and seismic forces. As turbines grow larger, they experience proportionally larger lateral forces. Large forces require larger section sizes and overall weight of the turbine. The objective of this study is to investigate the use of vibration isolation as a structural control measure to minimize the overall wind and seismic forces transmitted to the turbine. Passive control systems such as tuned mass dampers have previously been proposed to mitigate response to wind loading but have not generally been evaluated under seismic loading. This thesis discusses the potential use of a non-linear vibration isolator just below the wind turbine nacelle to decrease the structural response of the turbine under wind and seismic loading. The structural idealization of the wind turbine structure and the applied loading are presented. The force-displacement properties of the vibration isolator are discussed and the equations of motion are modified to include the isolator. A finite element model is created which includes wind and seismic loading and incorporates a vibration isolator. Simulations are performed to determine a number of key structural response variables without the vibration isolator, and with a vibration isolator having varied force-displacement properties. The changes in those key response variables are presented and discussed. It is concluded that vibration isolation is a viable method for reducing structural response of wind turbines. Some practical concerns and areas of future research are discussed.

This thesis contains two main parts. The first part presents a database compiling 137 landslide-triggering earthquakes (LTEs) worldwide, with magnitudes greater than the minimum observed threshold for causing landslides (M4.5), for the period of 1998 -2009. Our data sources include a comprehensive review of the existing literature on earthquake-triggered landslides (ETLs), and also a USGS-based earthquake catalog (PAGER-CAT) that contains information on earthquake-triggered secondary events. Only 14 earthquakes out of the 137 seismic events induced significant numbers of landslides (>250). We compared the number of ETLs with the total number of earthquakes with M ≥ 4.5 (n=68,734) during the same period of time. The results show that only 0.2 % of ETLs and only 4.5% of earthquakes of M > 6 resulted in landslide. In addition, we compiled a database of 37 large-scale landslides, involving initial failure volumes of greater than 20 Mm3 that occurred worldwide between 1900 to 2010. The database contains large-scale earthquake-triggered (n ETLs=18) and non-earthquake-triggered landslides (n NETLs=20), i.e., ca. 50% of large-scale landslides were induced by seismic activity. Surprisingly, the volume-temporal frequency curves of ETLs and NETLs show almost identical slopes and intercepts. Thus, for a given volume, the annual frequency of ETLs is almost identical to that of NETLs in the 110 year period. In contrast to previous studies, this thesis found that the volume of the largest landslide triggered by a given landslide-triggering earthquake is not a function of earthquake magnitude. Peak ground motions (PGA, PGV, and PSA) were calculated for the 18 large-scale ETLs at the site of each occurrence and the resulting values show a correlation with the volume of landslides below the threshold of ca. 80 Mm3. Above this threshold, the relationship between peak ground motions and ETL volume shows complex and nonlinear behavior. The results suggest that 1) other special conditions are required for significant earthquake-triggered landslides to occur, and 2) that very large earthquake-triggered landslides (volume greater than 80 Mm3) result from complex progressive failure mechanisms initiated by seismic shaking (i.e., above this threshold volume, landslide volume is independent of PGA, PGV, and PSA). A detailed analysis of the two 1985 Nahanni earthquakes and the North Nahanni rockslide triggered by the first main shock is carried out in the second part of the study. The North Nahanni rockslide, Northwest Territories, Canada was triggered by the earthquake of M=6.6 on October 5th, 1985. The slide occurred in a Palaeozoic carbonate sequence along a thrust fault, which partly follows bedding and partly cuts across bedding. The sliding surface within the limestone consisted of two planes; the lower plane dipped at 20° while the upper plane dipped at 35°. Slope stability analysis is performed using discontinuum numerical modeling. Static slope stability analyses indicate that the sliding rock was marginally safe for the sliding surface friction angles of 24o or higher. Dynamic analyses of the co-seismic movements are conducted by applying a series of sinusoidal waves to the base of the model. The amplitudes of the October earthquake's seismic waves are estimated using strong motion data available from the second main shock. The results, from the dynamic analysis indicate that the slope becomes unstable for given seismic inputs at a specific range of friction angles (24o to 30o) for the sliding surface and the deformation behavior of the North Nahanni rock masses is dependent on the frequency of the seismic signals. Because the static slope stability analysis showed that the slope was close to instability prior to the seismic shaking, we suggest that the 1985 Nahanni earthquake operated as a trigger event that accelerated the occurrence of the slide. This finding supports our earlier results of the global scale study, which showed that the triggering event does not change the general trend of the frequency-volume distribution of landslides; however, it can accelerate the occurrence of slope failure.

Aspendos Theatre still stands in fairly good condition although it has been constructed about 2200 years ago in Serik village of Antalya, Turkey. Aspendos Theatre is one of the most valuable historical buildings in Turkey. The fact that the structure had overcome numerous possible earthquakes during its lifespan in Antalya and located in second degree earthquake zone, makes the subject an interesting research topic. The earthquake analysis of Aspendos Theatre was conducted using Specification for Structures to be Built in Disaster Areas code and stress levels are investigated using 3D FE modeling. Also, the resonance state of the theatre under sound induced forces due to concerts and exhibitions performed in the theatre has been examined. Structural identification is performed to obtain certain structural characteristics by comparing experimentally measured and analytically obtained natural frequencies. The analytical model is constructed using solid members and the analysis is performed by using SAP2000 software. The elastic modulus of conglomerate used as building blocks in the Theatre is taken as 2350 MPa based on the experimental and analytical studies. The compressive and tensile strength of the theatre wall material is taken as 12 MPa and 1.2 MPa, respectively based on the previous studies conducted on conglomerate. When the maximum stress levels under combined effect of response spectrum and dead load analyses are examined, the level of compressive stress is found to be about 60% of the compressive strength. On the other hand, the tensile stresses developing at upper corners and bottom middle parts of the stage wall and mid-height central location of the exterior wall (on the vicinity of the front door) are calculated to be about 6.6 MPa, which are more than the assumed tensile strength. It has also been calculated that the level of sound that generates tensile failure is about 125 dB as the theatre gets into resonance state.

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Current codes of practice for the design of tall concrete chimneys provide conservative aseismic design guidelines in high seismic regions. A lack of experimental data related to the cyclic behaviour of chimney structures to severe earthquake excitation has resulted in the assumption that such structures are brittle and must be designed in the elastic range. This design approach results in expensive structures and is not consistent with the design philosophy commonly adopted for general structure which permits some inelastic response at the ultimate limit state event. A research program funded by the CICIND organisation has been undertaken to investigate the inelastic cyclic behaviour of tall reinforce concrete chimneys using both experimental and analytical techniques to determine whether the behaviour is brittle or ductile. The research has been divided into three parts; (a) overview of earthquake ground motions, review of the earthquake response of structures and review of chimney design code provisions, (b) detailed description of experimental research examining the cyclic behaviour of chimney sections and (c) development of an aseismic design and analysis procedure for reinforced concrete chimneys including code recommendations. (For complete synopsis open document)