Les applications des mesures dynamiques sur les bâtiments existants sont nombreuses : vérification de la vulnérabilité sismique des structures qui ont été construites avant l’apparition des règles parasismiques ; auscultation de la capacité des structures en situation post-sismique ou après des modifications au voisinage (creusement d’un tunnel à côté ou démolition des immeubles voisins par exemple). A l’heure actuelle, ce type de mesure permet le diagnostic d’une structure à l’échelle globale (toute la structure) alors que l’identification et la localisation des endommagements à l’échelle locale (chaque élément de la structure) restent encore à approfondir. Dans le cadre de cette thèse, le diagnostic à l’échelle locale des structures sera étudié. Cette thèse s’insère dans un contexte national de réévaluation des structures existantes du fait du nombre important de bâtiments à réhabiliter. Au sein du LOCIE, nous pensons que le comportement global des bâtiments est certes influencé par l’interaction sol-structure mais au moins autant par la qualité des connexions des éléments de structures entre eux. Il existe un besoin de qualification de ces connexions dont la variabilité du comportement peut provenir aussi bien de défauts de mise en œuvre (positionnement des armatures,…) que du vieillissement des structures. L’objectif principal de cette thèse est de proposer une méthode pouvant caractériser les liaisons entre les éléments de structure afin de pouvoir caler un modèle numérique. Ces caractérisations devaient être possibles à partir de mesures de sollicitations dynamiques. Une première étape de ce travail consistera à caractériser sur une partie de structure une liaison. Cela sera fait sur un portique en béton armé. Par la suite, cette méthode sera adaptée à une caractérisation au sein d’une structure de bâtiment. Pour cela nous ferons appel à la notion de sous-modèle. Un modèle numérique sera associé à cette méthode aussi bien sur la connexion simple que sur l’ensemble du bâtiment. Le travail de thèse s’appuiera sur l’utilisation et le développement de techniques concernant le traitement des données dynamiques ; la réduction de modèles ; l’expérimentation en laboratoire (échelle locale et échelle d’un élément de structure) et la modélisation numérique par éléments finis à plusieurs échelles / There are many of the examples of dynamics measurements applications in the existing building: verification of structural seismic vulnerability, which was constructed before the earthquake building code; auscultation of structural capacity in post-earthquake situation or after modification in surround environment (Excavation of tunnel or demolition the neighbour buildings for example). Currently, this measurement type enables the diagnosis a structure in global scale (a whole structure) while identification and localization of damage in local scale (each elements of the structure) remains to be explored. In this dissertation, diagnosis in locale scale will be studied. This study is significant for its contribution to the national reassessment of existing structures where there is the large number of buildings to be rehabilitated

<p>Civil engineering structures must provide an adequate and safe performance during their time of service, and the owners of these structures must have a reliable inspection strategy to ensure time-dependent damage does not become excessive. Visual inspection is the first step in every structural inspection; however, many elements in the majority of structures are difficult to access and require specialized personal and equipment. In an attempt to reduce the risk of the inspector and the cost of additional equipment, the use of Unmanned Aircraft Systems (UAS) has been increasing in the last years. The absence of standards and regulations regarding the use of UAS in inspection of structures has allowed the market to widely advertise Unmanned Aerial Vehicles (UAV) without protocols or qualifications that prove their effectiveness, leaving the owners of the structures to solely rely on claims of the vendors before deciding which technology suits their particular inspection needs. Focusing primarily on bridge inspection, this research aimed to address the lack of performance-based evaluation and standards for UAS, developing a validation criterion to evaluate a given UAS based on a repeatable test that resembles typical conditions in a structure. </p><p><br></p><p>Current applications of UAS in inspection of structures along with its advantages and limitations were studied to determine the current status of UAS technologies. A maximum typical rotor-tip-to-rotor-tip distance of an UAV was determined based on typical UAVs used in bridge inspection, and two main parameters were found to be relevant when flying close to structures: proximity effects in the UAV and availability of visual line of sight. Distances where proximity effects are relevant were determined based on several field inspections and flights close to structures. In addition, the use of supplementary technologies such as Global Positioning System (GPS) and Inertial Measurement Units (IMU) was studied to understand their effect during inspection. </p><p><br></p><p>Following the analysis, the author introduces the idea of a series of obstacles and elements inside an enclosed space that resemble components of bridge structures to be inspected using UAVs, allowing repeatability of the test by controlling outside parameters such as lighting condition, wind, precipitation, temperature, and GPS signal. Using distances based on proximity effects, maximum typical rotor-tip-to-rotor-tip distance, and a gallery of bridges and situations when flying close to bridge structures, a final arrangement of elements is presented as the evaluation chamber. Components inside the evaluation chamber include both “real” steel and concrete specimens as well as those intended to simulate various geometric configurations on which other features are mounted. Pictures of damages of steel and concrete elements have been placed in the internal faces of the obstacles that can be assessed either in real-time flight or in post-processing work. A detailed comparison between the objectives of this research project and the results obtained by the evaluation chamber was performed using visual evaluation and resolution charts for the images obtained, the availability of visual line of sight during the test, and the absence of GPS signal.</p><p><br></p><p>From the comparison and analysis conducted and based on satisfactory flight results as images obtained during flights, the evaluation chamber is concluded to be a repeatable and reliable tool to apply to any UAS prior to inspect bridges and other structures, and the author recommends to refrain from conducting an inspection if the UAS does not comply with the minimum requirements presented in this research work. Additionally, this research provided a clearer understanding of the general phenomenon presented when UAVs approach structures and attempts to fill the gap of knowledge regarding minimum requirements and criterion for the use of UAS technologies in inspection of structures.</p>