Optimization procedure for the strut-and-tie method considering the stiffness of concrete in compression
Date
2023
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Abstract
An optimization procedure is proposed for finding an optimal truss for the Strut-and-Tie method used to design the steel reinforcement in concrete structural elements. The basis of the procedure is to maximize the global stiffness of the element by optimizing the reinforcement layout but considering the stiffness of concrete in the compressed zones of
the element during the optimization. The hydrostatic stress is used to determine those zones, which change along the maximization. The stiffness provided by the concrete in compression to the overall system during the optimization, result in optimal topologies different from those found in the literature, which, when translated into admissible trusses
for the Strut-and-Tie method, in most cases (analyzed by numerical modeling), lead to reinforced concrete elements that are better in terms of higher ratios of ultimate load over the weight of steel, and also in terms of spreading more evenly the cracks in the damaged zones of the element. Three typical cases from the literature are analyzed. For each case, the
optimal topology and the truss structures derived from it are shown. Finally, the performance of each Strut and Tie system is evaluated using Non-lineal Finite Elements analysis and compared to existing models.
Description
Tesis (Master of Science in Engineering)--Pontificia Universidad Católica de Chile, 2023
Keywords
Strut and Tie, Compliance minimization, Homogenization method, Hydrostatic stress, Reinforced concrete, Structural optimization