A Study on the Effects of Openings on Seismic Behavior of Reinforced Concrete Shear Walls
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Date
2017-03
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Addis Ababa University
Abstract
The objective of this study was to better understand the effects of size and location of openings on seismic behavior of reinforced concrete shear walls using response spectrum analysis and with the help of ETABS15.2.2, finite element software package. The shear walls on 22-storied 40/60 saving house projects were used as a case study. There are three types of shear walls in those buildings. The first shear wall, SW1, has single band of asymmetric window openings. The second shear wall, SW2, has single band of asymmetric door openings. The third shear wall, SW3, has two bands of symmetric door openings. The study was repeated in 10-storied and 40-storied models of the above mentioned shear walls in order to get more comprehensive conclusions. The lateral loads were applied according to ES EN 1998-1:2015’s provisions by assuming as if all shear walls were located in the highest seismic zone of Ethiopia. Comparison of the different models was made relative to seismic responses (lateral displacement, storey drift, base shear and shell’s internal force distributions) and the results were discussed, tabulated and/or plotted graphically. For each shear wall, the study was carried out by varying the sizes of openings from small to large openings. It was concluded that, though introducing smaller openings reduces the lateral displacement at the top, story drift and shell’s internal forces of a wall, using very large size of openings throughout the height of the wall significantly increases the seismic responses. The effect of location of openings was also investigated by considering asymmetric, symmetric and staggered location of openings and it was concluded that, for almost all shear walls, the shear wall with symmetric location of both window and door openings gives less lateral displacement, storey drift and shell forces than the shear walls with asymmetric and staggered locations. Moreover, for almost all shear walls, using shear wall model with different size of symmetric openings, which gradually increases from the bottom storey to the top most storey, is more effective in reducing the seismic responses than even the corresponding solid shear wall without any opening or with symmetric and/or smaller openings. It was also concluded that asymmetric location of openings should be avoided as much as possible. Therefore, caution should be taken during providing openings in reinforced concrete shear walls and the architect and the structural engineer should initially work together in order to avoid unfavorable size and/or location of shear wall openings, which may perhaps leave the wall defenseless to transversal components of earth quake load.
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Structural Engineering