Due to their limited ductile properties, pre-1970s reinforced concrete buildings pose a significant threat to the general public during earthquakes. It is essential to understand how these structures behave during ground motion. This project deals with assessing the load capacity of concrete slab systems in these older buildings, should a column fail. As a part of a larger NEESR Grand Challenge research project led by Professor Moehle at UC Berkley, a series of experimental tests on two-way square concrete slabs each supported on nine columns will be carried out. Before constructing the specimens, analysis of the expected failure loads on the slab systems is performed in order to finalize specimen design and material properties and design the appropriate load measurement system. In this case, load cells are designed and fabricated to measure the appropriate strains during the testing. Three separate analyses are executed including an OpenSees model, yield line calculations, and utilization of the load enhancement method. Ultimately, the analyses produce the six reaction forces at the column; shear in the x and y directions, moment in the x and y directions, torsion, and axial load. This allows for a sensitivity analysis in Matlab to obtain the most appropriate dimensions for the load cells. The expected failure loads were higher than anticipated, and the column design had to be altered to accommodate a higher shear. The test specimen has been designed and drafted into AutoCAD. The next steps include fabrication and testing of the load cells and then constructing and testing the two concrete slabs. The tests should occur sometime around the end of this year.
University of Virginia
REU Institution: University of California, San Diego
REU Advisors: Tess Kinderman, Tezeswi Tadepalli, and Lelli Van Den Einde
Mentor: Dr. Tara Hutchinson
Graduate Student Mentor: Saurabh Prasad
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