Increasing demands, shrinking financial and human resources, and increased infrastructure deterioration have made the task of maintaining the infrastructure systems more challenging than ever before. Life-cycle cost analysis (LCCA) is an important tool for transportation infrastructure management, which is used extensively to support project level decisions, and is increasingly being applied to enhance network level analysis. However, traditional LCCA tools cannot practically and effectively utilize expert knowledge and handle ambiguous uncertainties. The main objective of this dissertation was to develop enhanced LCCA models using soft computing (mainly fuzzy logic) techniques. The proposed models use available "real-world" information to forecast life-cycle costs of competing maintenance and rehabilitation strategies and support infrastructure management decisions. A critical review of available soft computing techniques and their applications in infrastructure management suggested that these techniques provide appealing alternatives for supporting many of the infrastructure management functions. In particular, LCCA often utilizes information that is uncertain, ambiguous and incomplete, which is obtained from both existing databases and expert opinion. Consequently, fuzzy logic techniques were selected to enhance life-cycle cost analysis of transportation infrastructure investments because they provide a formal approach for the effective treatment of these types of information. The dissertation first proposes a fuzzy-logic-based decision-support model, whose inference rules can be customized according to agency's management policies and expert opinion. The feasibility and practicality of the proposed model is illustrated by its implementation in a life-cycle cost analysis algorithm for comparing and selecting pavement maintenance, rehabilitation and reconstruction (MR&R) policies. To enhance the traditional probabilistic LCCA model, the fuzzy-logic-based model is then incorporated into the risk analysis process. A fuzzy logic approach for determining the timing of pavement MR&R treatments in a probabilistic LCCA model for selecting pavement MR&R strategies is proposed. The proposed approach uses performance curves and fuzzy-logic triggering models to determine the most effective timing of pavement MR&R activities. The application of the approach in a case study demonstrates that the fuzzy-logic-based risk analysis model for LCCA can effectively produce results that are at least comparable to those of the benchmark methods while effectively considering some of the ambiguous uncertainty inherent to the process. Finally, the research establishes a systematic method to calibrate the fuzzy-logic based rehabilitation decision model using real cases extracted from the Long Term Pavement Performance (LTPP) database. By reinterpreting the model in the form of a neuro-fuzzy system, the calibration algorithm takes advantage of the learning capabilities of artificial neural networks for tuning the fuzzy membership functions and rules. The practicality of the method is demonstrated by successfully tuning the treatment selection model to distinguish between rehabilitation (light overlay) and do-nothing cases. / Ph. D.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The concrete is the principal featured in the construction industry, in terms of volume and demand of natural resources for its production. It is need to seek sustainability through researches to assist in the upgrade industry. Studies for this purpose have been gaining ground in different areas, and exploring important information to human knowledge. Besides the environmental assessment, it is interesting to apply economic aspects. This research seeks to assess the sustainability of structural concrete by durability testing of carbonation in the laboratory and analyzing the modular Life Cycle Assessment (LCA - m) through the computer program SimaPro and Life Cycle Costs Analysis (LCCA). Evaluated the sustainability assessment of a reinforced concrete pillar of a standard building in Santa Maria region, RS - Brazil, ranging from the cement type (CPII - Z, CPIV and CPV-ARI) and characteristic strength levels (fck 30 and 50 MPa), since the phases of production, use, maintenance and deconstruction/recycling of this functional unit (period between cradle-togate). It is useful life was estimate by the analysis of carbonation coefficients, by natural and accelerated methods. It was conclude that the increase in concrete strength from 30 to 50 MPa is favorable in all the studied factors. The cement variation was decisive for fck = 30 MPa, for the life of the project for minimum standard was not met with CPIV and CPV-ARI. The cement CPII-Z achieved the best results. / O concreto é o principal destaque na indústria da construção, em termos de volume e demanda de recursos naturais para sua produção. É preciso buscar sua sustentabilidade, através de pesquisas que auxiliem na atualização da indústria. Estudos com esta finalidade vêm ganhando espaço nas diferentes áreas, e explorando informações importantes para o conhecimento humano. Além da avaliação ambiental, torna-se interessante a aplicação de aspectos econômicos. Esta pesquisa busca avaliar quantitativamente a sustentabilidade do concreto estrutural através de ensaio de durabilidade à carbonatação em laboratório utilizando Análise do Ciclo de Vida modular (ACV-m) por meio do programa computacional SimaPro e do Custo do Ciclo de Vida (CCV). Avaliou-se a sustentabilidade de um pilar de concreto armado de uma edificação padrão da região de Santa Maria, RS Brasil, variando-se o tipo de cimento (CPII-Z, CPIV e CPV-ARI) e níveis de resistência característica à compressão (fck 30 e 50 MPa), desde as fases de produção, de uso, de manutenção e de desconstrução/reciclagem desta unidade funcional estrutural (período compreendido entre berço e o túmulo). Sua vida útil foi estimada pela análise dos coeficientes de carbonatação, por meio dos métodos natural e acelerado. Concluiu-se que o acréscimo da resistência do concreto de 30 para 50 MPa é favorável em todos os fatores estudados. A variação do cimento foi decisiva para fck = 30 MPa, pois a vida útil de projeto mínima por norma não foi atingida com CPIV e CPV-ARI. O cimento CPII-Z obteve os melhores resultados.

This diploma thesis deals with problematics of tram tracks with vegetation cover. The research part of the work contains the overview of currently used systems of green tram tracks in Europe and their advantages and disadvantages with respect to sustainability of a vegetation cover. 3 different variations of a green tram track at a particular location in Brno at Nové Sady street are compared in the second part of the thesis. The low maintenance vegetation and intesively planted vegetation are compared from both financial and ecological points of view. Life cycle costs analysis and multicriterial analysis were used for the comparison.