الفهرس | Only 14 pages are availabe for public view |
Abstract This study explores the structural behavior of connections between multi-cell columns and foundations under bending loads. The term ”multi-cell” refers to sections featuring multiple longitudinal hollow cores separated by thin webs. A total of eight specimens were cast, cured, and tested under a single loading line system until failure. To facilitate this study, a control specimen was created to serve as a benchmark, allowing for the assessment of the impact of various parameters on the connection. These parameters include embedment depth, the number of cells in the column, presence of shear studs, internal plates, and concrete infill within the column. Each specimen features a footing measuring 80 cm x 80 cm with a 25 cm depth, reinforced with nine rebars in each direction. The base plate measures 20 cm x 20 cm with a 6 mm thickness, and the column measures 12 cm x 12 cm with a 1.5 m height and a 6 mm wall thickness. The performance of the connection was evaluated based on criteria such as crack load, ultimate load, loaddisplacement curves, energy absorption capacity, ductility index, and crack pattern, aiming to determine the efficacy of the tested parameters. Results indicated that increasing the embedment depth from 8 cm to 12 cm improved connection behavior, with the ultimate load and energy absorption increasing by 175% and 225.8%, respectively. Changes in the column’s cross-section cell geometry also significantly affected performance: increasing the number of cells from two to three boosted the ultimate displacement by 116.31%, while reducing the number of cells from two to one decreased it by 87.62%. The presence of shear studs in the embedment area positively influenced connection behavior, enhancing ultimate load, displacement, ductility index, and energy absorption by notable percentages. Furthermore, incorporating internal platesand additional reinforcement into the footing markedly improved structural behavior. Filling the column with concrete yielded mixed results, with an increase in ultimate load but reductions in displacement, ductility, and energy absorption. A three-dimensional finite element (FE) model was developed using ABAQUS/CAE software to simulate the different materials and configurations of the eight specimens. Comparisons between experimental and numerical results showed good agreement. The average percentage of the first crack loads of the tested specimens between the experimental results and the numerical results was 4.69%, while the average percentage of the ultimate loads of the tested specimens between the experimental results and the numerical results was 4.39%. In addition, the average percentage of the maximum displacement of the tested specimens between the experimental results and the numerical results was 6.29%. Therefore, there is a good agreement between experimental and numerical results. |