Experimental investigation of topology-optimized reinforced concrete beams with varying volume Fractions
Author(s)Liu, Yan,M.Eng Ph.D.Massachusetts Institute of Technology.
Massachusetts Institute of Technology. Department of Civil and Environmental Engineering.
Josephine V. Carstensen.
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Researchers have developed algorithms for topology optimization of concrete and reinforced concrete designs. However, concrete is a complex composite material and there is still a lack of validation of fabricated topology-optimized designs of concrete structures. It hinders the progress of incorporating topology-optimized structural components in the civil engineering industry. This work aims to address the issue stated above by experimentally evaluating deep reinforced concrete beams with strut-and-tie models (STMs) designed with the Hybrid Truss-Continuum Topology Optimization Algorithm . The algorithm is chosen to alleviate the need for post-processing as it incorporates the discrete nature of the steel reinforcement in the design problem which allows continuous force flow within the concrete phase of the design. The hybridity, therefore, originates from a truss element ground structure design in the density-based continuum topology optimization framework. The resultant optimized truss elements represent the tensile load path whereas the optimized continuum structure indicates the compressive load path. When using STM to design reinforced concrete beams, there will be underutilized areas within the concrete phase where minimal force is predicted to be present. In this work, we experimentally investigate the consequences of removing material in these regions. The used algorithm  is adjusted to enable control of the volume fraction of both the reinforcing and the concrete phase. A preliminary relationship between the reduction in strength of the reinforced concrete beams and the extracted volume of the underutilized areas is explored. The design domain is a 2D prismatic deep reinforced concrete beam with dimensions 3 feet by 9 inches by 2 inches. The tested beams are simply supported with a single point load at mid-span. Using the same steel volume, concrete volume fractions of 75%, 85%, 90%, 95%, and 100% are presented and experimentally tested.
Thesis: M. Eng., Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, 2019Cataloged from PDF version of thesis. Page 52 blank.Includes bibliographical references (pages 49-51).
DepartmentMassachusetts Institute of Technology. Department of Civil and Environmental Engineering
Massachusetts Institute of Technology
Civil and Environmental Engineering.