Lifetime Serviceability and Safety of Highway Bridges Under Climate Change

Abstract

This dissertation aims to address the growing challenge of ensuring the serviceability and safety of concrete highway bridges amidst climate change, with a particular emphasis on the Canadian scenario where a significant backlog in maintenance exists. A particular focus is set on characterizing the accelerated deterioration of bridges due to climatic change and assessing its impact on bridge lifetime performance, from regular service to extreme collision scenarios. The research unfolds in three phases. First, it assesses the impact of climate change on chloride-induced damage, a significant deterioration factor for concrete bridges. This phase includes two parts: one is to establish a provincial database for Ontario that documents chloride exposure over time and different traffic and weather conditions. Additionally, the study utilizes machine learning to create Corrosion Hazard Maps, which reveal spatial variations in the risk of corrosion damage to bridges under different climate change scenarios. Building on the first phase which focuses on serviceability, the second phase evaluates how climate change exacerbates the safety risks associated with both service loads and extreme vehicle-bridge collisions. For service loads, reliability-based methodologies are developed to assess the time-varied safety of bridges, considering both traditional vehicular loads and emerging traffic patterns (i.e., automated truck platooning). In the case of vehicle-bridge collisions, the approach focuses on employing a fragility-based approach for evaluating the lifetime performance of concrete highway bridges that are exposed to both episodic (vehicle-bridge collision) and chronic (corrosion) hazards. The final phase expands the scope of the first and second phases from individual bridges to entire transportation networks. It introduces a multiscale, risk-based assessment framework that prioritizes bridge rehabilitation to accommodate truck platooning and mitigate collision risks. Overall, the dissertation promotes a comprehensive, resilient framework for bridge life-cycle management, integrating various stages from design to maintenance within the broader context of socio-economic factors.