This master’s thesis investigates computational methods for determining the deflections of reinforced concrete structures, with a particular emphasis on the influence of cracking, creep, and shrinkage of concrete. These time-dependent phenomena significantly affect the long-term deformation behavior of structural members and, if not properly considered, can compromise both the durability and serviceability of the structure. The thesis begins with a presentation of the theoretical background. Special attention is given to cracking and the composite action between concrete and reinforcement in the tensile zone. Three computational methods are then introduced. The simplest is the simplified method prescribed by the standard Eurocode 2 (SIST EN 1992-1-1:2005), which is suitable only for estimating deflections of basic structural elements. More accurate results can be obtained using methods that involve solving a system of nonlinear structural equations. For simple elements, these can be solved relatively easily, while more complex structures require the use of the finite element method. This is done using appropriate commercial software, such as Sofistik, or research-oriented tools, such as NFIRA, which operates within the Matlab environment. The practical application of these methods is demonstrated through several case studies: a simply supported beam, a cantilever beam, a single-span slab and a slab extending over multiple spans. By comparing the results obtained from different approaches, the study evaluates their relative accuracy and reliability. The findings demonstrate that taking the effects of cracking and rheological behavior into consideration is essential for realistic deflection assessment and, consequently, for ensuring the long-term serviceability of reinforced concrete structures.
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