Active travel, encompassing walking and cycling, has emerged as a vital component in pursuing sustainable, healthy, and efficient urban transportation systems. This thesis comprises two interrelated studies that collectively contribute to a comprehensive understanding of active travel behavior and its analysis within the Canadian context. At the first step, we focused on the data prerequisites and sources required for active accessibility analysis, systematically evaluates geographic accessibility measures and data specificity essential to assessing walking and cycling in the Canadian urban landscape. As accessibility increasingly takes center stage in urban transportation policies, it becomes imperative to understand the unique data requirements and methodological considerations for these non-motorized modes. In the subsequent phase of our research, we extensively analyzed active travel behavior trends in Canada, spanning three decades from 1986 to 2015. This study uses data from Canada’s General Social Survey to examine individual preferences and behaviors related to walking and cycling. The focus is mainly on understanding how these behaviors vary according to different trip purposes and geographical contexts. Our approach involved the calibration of empirical impedance functions to gain insights into the willingness of individuals to travel to various destinations using active modes of transportation. This aspect of the study is crucial in quantifying the time individuals are willing to allocate to walk and cycle to reach their destinations. The investigation notably provides a historical perspective on the evolution of active mobility over the past 35 years. This historical analysis is pivotal in unraveling the changes in active travel behavior, influenced by factors such as urban development trends, societal attitudes towards health and environmental sustainability, and modifications in transportation infrastructure and policy frameworks. Our findings reveal significant and consistent disparities in trip durations between walking and cycling modes, accompanied by intriguing temporal variations over the years. / Thesis / Master of Applied Science (MASc) / Active travel, encompassing walking and cycling, is pivotal in fostering sustainable and healthy urban transportation systems. This thesis comprises two interconnected studies comprehensively addressing the complexities and imperatives of active travel analysis within the Canadian context. The first chapter evaluates geographic accessibility measures and data specifics necessary for assessing these modes in the Canadian context, shifting the focus to data prerequisites and sources critical for active accessibility analysis. This comprehensive analysis compares metrics, origin-destination considerations, geographic scales, and methods for calculating travel time and distance for walking and cycling. Beyond its relevance in Canada, this examination yields broader insights into the challenges and considerations associated with active travel accessibility analysis worldwide. The second chapter embarks on a journey through three decades of active travel behavior in Canada. Utilizing data from Canada’s General Social Survey, this research calibrates empirical impedance functions to elucidate individuals’ willingness to undertake trips to various destinations by walking and cycling. The study not only reveals evolving patterns in active mobility but also offers valuable insights for urban planners and policymakers seeking to elevate walking and cycling as essential components of urban transportation in Canada. These integrated studies contribute significantly to the ongoing discourse on active travel and accessibility, emphasizing the need for a transition from mobility-centric to accessibility-focused urban transportation policies. This transition holds the key to creating more sustainable, vibrant, and healthier cities for the future.

A number of methods have been proposed that utilize the time domain transformations of the frequency dependent impedance functions to perform time-history analysis of structures accounting for soil-structure interaction (SSI). Though these methods have been available in literature for a number of years, this study is the first to rigorously examine the limitations and advantages of these methods in comparison to one another. These methods contain certain stability issues that required investigating which lead to the formation of an analysis procedure that assesses a transform method’s stability. The general applicability of these methods was demonstrated by utilizing them to model increasingly sophisticated reference problems. Additionally the suitability of these methods to being incorporated into hybrid simulations of nonlinear inelastic structures considering soil-structure interaction was confirmed. The modelling of a nonlinear structure considering soil-structure interaction is an improvement over the most common modelling strategies that model solely linear-elastic behaviour.

A number of methods have been proposed that utilize the time domain transformations of the frequency dependent impedance functions to perform time-history analysis of structures accounting for soil-structure interaction (SSI). Though these methods have been available in literature for a number of years, this study is the first to rigorously examine the limitations and advantages of these methods in comparison to one another. These methods contain certain stability issues that required investigating which lead to the formation of an analysis procedure that assesses a transform method’s stability. The general applicability of these methods was demonstrated by utilizing them to model increasingly sophisticated reference problems. Additionally the suitability of these methods to being incorporated into hybrid simulations of nonlinear inelastic structures considering soil-structure interaction was confirmed. The modelling of a nonlinear structure considering soil-structure interaction is an improvement over the most common modelling strategies that model solely linear-elastic behaviour.

Research performed on the subject of dynamic soil-structure interaction (SS) concerning railway bridges is presented in this thesis with the focus on simply supported railway bridges supported by shallow foundations in soil strata on bedrock. The research aims to obtain insight into the SSI of high-speed railway bridges and to provide recommendations on how to model the soil-bridge system from a design perspective. A three-dimensional (3D) simply supported soil-bridge model was first developed and the effects from model assumptions made on the soil-foundation system was evaluated in a 3D setting (paper I). The soil-foundation system was then refined and a model assumptions study was performed in order to evaluate the effects of model assumptions on impedance functions, including the influence of the permanent load acting on the soil-foundation system (paper II). Finally, a study of the assembled soil-bridge system was performed in an extensive parametric study including a set of 2D bridge models in combination with a set of shallow foundations in soil strata on bedrock (paper III). A supplementary section related to paper III was also added in this thesis, showing the effects of the substructure mass. The model assumptions made when creating the soil-foundation model and the soil-bridge model can be very important and must be made with care. The permanent load acting on the soil-foundation systems of shallow foundations may alter the impedance functions significantly. The substructure mass may alter the behavior of the soil-bridge system depending on its magnitude, and neglecting it gives inaccurate results. The 3D effects of SSI do not cause high vibrations due to modes other than the first bending mode, and assuming a 2D bridge model is generally acceptable. The effects of SSI on the soil-bridge systems with shallow soil strata are largely dependent on the ratio between the natural frequency of the bridge and the fundamental frequency of the soil. Depending on the value of this ratio, the effect of including SSI in bridge models may contribute to the bridge obtaining a negligible, conservative, or non-conservative response, as compared to the bridge with the assumption of non-flexible supports. / Forskning i syfte att utröna effekten av dynamisk jord–struktur-interaktion (SSI)på järnvägsbroar presenteras i denna avhandling med huvudfokus på fritt upplagdabroar med stöd av plattgrundlagda fundament i jordar på fast berggrund. Forsknin-gen syftar till att ge förståelse för interaktionen mellan jord och järnvägsbroar samtatt ge rekommendationer på hur systemet kan modelleras ur ett designperspektiv.En tredimensionell (3D) fritt upplagd jord–bromodell utvecklades först och effek-terna av modellantaganden gjorda på jord–grundläggningssystemet utvärderadesi en 3D miljö (artikel I). Jord–grundläggningssystemet förfinades och en studiegenomfördes för att utvärdera effekterna av modellantaganden på impedansfunk-tioner, inklusive påverkan av den permanenta belastningen som verkar på jord–grundläggningssystemet (artikel II). Slutligen utfördes en omfattande parametriskstudie av det sammansatta jord–brosystemet där en uppsättning tvådimensionella(2D) bromodeller kombinerades med en uppsättning jordar (artikel III). Ett kom-pletterande avsnitt relaterat till artikel III lades till i denna avhandling som visareffekterna av massan av underbyggnaden på jord–brosystemet.De modellantaganden som görs vid skapandet av jord–grundläggningsmodeller ochjord–bromodeller kan vara mycket viktiga och bör utföras med varsamhet. Den per-manenta belastningen som verkar på jord–grundläggningssystemet kan väsentligtförändra impedansfunktionerna. Massan av underbyggnaden kan vidare ändra re-sponsen i jord–brosystemet, beroende på dess storlek, och att försumma den kan gefelaktiga resultat. De 3D effekterna av SSI orsakar inte höga vibrationer på grundav andra moder än den första böjmoden, och att anta en 2D bromodell är såledesgenerellt sett motiverat.Effekterna av SSI på jord–brosystemet i grunda jordar beror till stor del av kvotenmellan brons naturliga frekvens och jordens fundamentala frekvens. Beroende påvärdet på denna kvot kan effekten av att inkludera SSI i bromodeller bidra till attbron får en försumbar, konservativ, eller icke-konservativ respons, i jämförelse medbron med antagandet om fasta upplag. / <p>QC 20200903</p>

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