Otimização multiobjetivo aplicada a projetos de lajes maciças e pré-fabricadas com vigotas treliçadas

• Autor(a) principal: Almeida, Leandro Silva
• Data de Publicação: 2021
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFS
• Texto Completo: http://ri.ufs.br/jspui/handle/riufs/16897
• topic: Engenharia civil; Lajes; Custo; Mão de obra; Otimização multiobjetivo; Duração de execução; Quantidade de mão de obra; Multi-objective optimization; Slabs; Cost; Execution duration; Amount of labor; ENGENHARIAS::ENGENHARIA CIVIL

Construction industry is an important sector of the economy that representes, approximately, 10% of the world GDP, consuming considerable percentages of global energy and raw materials. Concrete and steel are the main materials used in the construction of structures and represent a great impact on their cost, justifying the growing interest in the use of optimization techniques applied to structural reinforced concrete systems in buildings. Recent studies indicate that, in recent years, the most used slabs in construction are those in reinforced concrete, especially those unidirectional, and approaches to modifying projects in order to reduce costs are based on the intuition and skills of the designers. Taking into account more complex processes, the modifications could make the project uneconomical, with a longer execution time and requiring a greater amount of workers to complete the services. This work aims to apply multi-objective optimization in the design of solid and rib precast ribbed concrete slabs with a focus on minimizing cost, execution duration and amount of labor, emphasizing the integration of the project with the execution planning. The design variables for the solid reinforced concrete slab are thickness and amout of reinforcement. For the precast ribbed concrete slab the design variables are the filler thickness, rib axis distances and amount of reinforcement. In addition to these variables, there are also design variables related to the specific workers of each function of the work. As for restrictions, these include the criteria related to the design in the Ultimate Limit State and the verifications in the Service Limit State. In addition, there are also restrictions for minimum and maximum amounts of labor. In the study, four cases were evaluated. For case 1, the objective function was the cost of the slabs, and for case 2, the execution duration was minimized. In cases 3 and 4, multiobjective optimization was applied, where the objective functions were slab cost, execution duration and amount of labor. In each case, three projects with different slab spans were studied. Among some results, it is highlighted that, in case 4, there was a tendency that the lower cost corresponds to the longer duration and the lower amount of labor, both for the solid slab and for the prefabricated slab. In this context, due to the conflict of objective functions, the application of multiobjective optimization enables a larger set of optimal solutions for the decision maker.