Concrete Bridges In Aggressive Environments

Essential infrastructures such as bridges are designed to provide a long-lasting and intergenerational functionality. In those cases, sustainability becomes of paramount importance when the infrastructure is exposed to aggressive environments, which can jeopardise their durability and lead to significant maintenance demands. The assessment of sustainability is however often complex and uncertain. The present study assesses the sustainability performance of 16 alternative designs of a concrete bridge deck in a coastal environment on the basis of a neutrosophic group analytic hierarchy process (AHP). The use of neutrosophic logic in the field of multi-criteria decision-making, as a generalisation of the widely used fuzzy logic, allows for a proper capture of the vagueness and uncertainties of the judgements emitted by the decision-makers. TOPSIS technique is then used to aggregate the different sustainability criteria. From the results, it is derived that only the simultaneous consideration of the economic, environmental and social life cycle impacts of a design shall lead to adequate sustainable designs. Choices made based on the optimality of a design in only some of the sustainability pillars will lead to erroneous conclusions. The use of concrete with silica fume has resulted in a sustainability performance of 46.3% better than conventional concrete designs.

Nine chapters by a group of authors run from site investigation to assessment, repair, thermal response, structural types, and joints and substructures.

This report proposes guidelines and presents research findings that are expected to advance and facilitate the use of CFRP systems in bridge applications. In addition, five design examples that illustrate the step-by-step use of the proposed guide specifications are provided. Carbon fiber reinforced polymer (CFRP) is becoming a recognized alternative to traditional construction materials in a wide range of civil engineering applications. An example of such applications is the use of CFRP cables or bars as prestressing tendons for concrete bridge girders, especially in aggressive environments where steel prestressing strands are susceptible to corrosion. Despite their promise, CFRP prestressing tendons have not frequently been used for bridge construction in the United States; their use has been hampered by the lack of recognized design specifications.