Monitoring of Dynamic Bridge Behaviour Using Digital Image Correlation

Bridges are a critical part of North America’s transportation network that need to be assessed frequently to inform bridge management decision making. Visual inspections are usually implemented for this purpose, during which inspectors must observe and report any excess displacements or vibrations. Unfortunately, these visual inspections are subjective and often highly variable and so a monitoring technology that can provide quantitative measurements to supplement inspections is needed. Digital Image Correlation (DIC) is a novel monitoring technology that uses digital images to measure displacement fields without any contact with the bridge. In this research, DIC and accelerometers were used to investigate the dynamic response of a railway bridge reported to experience large lateral displacements. Displacements were estimated using accelerometer measurements and were compared to DIC measurements. It was shown that accelerometers can provide reasonable estimates of displacement for zero-mean lateral displacements. By comparing measurements in the girder and in the piers, it was shown that for the bridge monitored, the large lateral displacements originated in the steel casting bearings positioned above the piers, and not in the piers themselves. The use of DIC for evaluating the effectiveness of rehabilitation of the LaSalle Causeway lift bridge in Kingston, Ontario was also investigated. Vertical displacements were measured at midspan and at the lifting end of the bridge during a static test and under dynamic live loading. The bridge displacements were well within the operating limits, however a gap at the lifting end of the bridge was identified. Rehabilitation of the bridge was conducted and by comparing measurements before and after rehabilitation, it was shown that the gap was successfully closed. Finally, DIC was used to monitor the midspan vertical and lateral displacements in a monitoring campaign of five steel rail bridges. DIC was also used to evaluate the effectiveness of structural rehabilitation of the lateral bracing of a bridge. Simple finite element models are developed using DIC measurements of displacement. Several lessons learned throughout this monitoring campaign are discussed in the hope of aiding future researchers.

The Evolution and Reform of Summary Trials in Canadian Military Justice

There is a place where a Canadian citizen can be sent to 30 days detention, by someone who is not a judge, without being represented by counsel, and without having a meaningful right to appeal. It is the summary trial system of the Canadian Armed Forces. This thesis analyses that system and suggests reforms. It is aimed at those who have an interest in improving the administration of military justice at the unit level but want to sufficiently understand the issues before doing so. Through a classic legal approach with elements of legal history and comparative law, this study begins by setting military justice in the Canadian legal firmament. The introductory chapter also explains fundamental concepts, first and foremost the broader notion of discipline, for which summary trial is one of the last maintaining tools. Chapter II describes the current system. An overview of its historical background is first given. Then, each procedural step is demystified, from investigation until review. Chapter III identifies potential breaches of the Charter, highlighting those that put the system at greater constitutional risk: the lack of judicial independence, the absence of hearing transcript, the lack of legal representation and the disparity of treatment between ranks. Alternatives adopted in the Canadian Armed Forces and in foreign jurisdictions, from both common law and civil law traditions, in addressing similar challenges are reviewed in Chapter IV. Chapter V analyses whether the breaches could nevertheless be justified in a free and democratic society. Its conclusion is that, considering the availability of reasonable alternatives, it would be hard to convince a court that the current system is a legitimate impairment of the individual’s legal rights. The conclusion Chapter presents options to address current challenges. First, the approach of ‘depenalization’ taken by the Government in recent Bill C-71 is analysed and criticised. The ‘judicialization’ approach is advocated through a series of 16 recommendations designed not only to strengthen the constitutionality of the system but also to improve the administration of military justice in furtherance of service members’ legal rights.

Physical and Chemical Performance Testing of Ontario Asphalt Pavements

Thermal and fatigue cracking are the two of the major pavement distress phenomena that contribute significantly towards increased premature pavement failures in Ontario. This in turn puts a massive burden on the provincial budgets as the government spends huge sums of money on the repair and rehabilitation of roads every year. Governments therefore need to rethink and re-evaluate their current measures in order to prevent it in future. The main objectives of this study include: the investigation of fatigue distress of 11 contract samples at 10oC, 15oC, 20oC and 25oC and the use of crack-tip-opening-displacement (CTOD) requirements at temperatures other than 15oC; investigation of thermal and fatigue distress of the comparative analysis of 8 Ministry of Transportation (MTO) recovered and straight asphalt samples through double-edge-notched-tension test (DENT) and extended bending beam rheometry (EBBR); chemical testing of all samples though X-ray Fluorescence (XRF) and Fourier transform infrared analysis (FTIR); Dynamic Shear Rheometer (DSR) higher and intermediate temperature grading; and the case study of a local Kingston road. Majority of 11 contract samples showed satisfactory performance at all temperatures except one sample. Study of CTOD at various temperatures found a strong correlation between the two variables. All recovered samples showed poor performance in terms of their ability to resist thermal and fatigue distress relative to their corresponding straight asphalt as evident in DENT test and EBBR results. XRF and FTIR testing of all samples showed the addition of waste engine oil (WEO) to be the root cause of pavement failures. DSR high temperature grading showed superior performance of recovered binders relative to straight asphalt. The local Kingston road showed extensive signs of damage due to thermal and fatigue distress as evident from DENT test, EBBR results and pictures taken in the field. In the light of these facts, the use of waste engine oil and recycled asphalt in pavements should be avoided as these have been shown to cause premature failure in pavements. The DENT test existing CTOD requirements should be implemented at other temperatures in order to prevent the occurrences of premature pavement failures in future.