01-07-2012, 08:04 AM
[Thesis] Experimental and numerical investigations of higher mode effects on seismic inelastic response of reinforced concrete shear walls
Author: Iman Ghorbanirenani | Size: 13 MB | Format: PDF | Year: December 2010 | pages: 254
Abstract
Past numerical simulations performed by previous researchers have shown that higher mode response can be significant for high-rise reinforced concrete shear walls used in building structures to resist lateral loads, when subjected to ground motions rich in high frequency that are expected in earthquakes occurring in Eastern North America. Higher mode response can lead to the development of plastic hinges in the upper portion of walls, in addition to the base plastic
hinge assumed in design according to current codes and design standards. Higher mode effects can also result in significant dynamic shear amplification at the base of walls, in excess of the shear resistance prescribed in current code documents. Experimental testing was needed on reinforced concrete walls under Eastern North America earthquake motions to validate these higher mode effects predicted by numerical simulations. This thesis presents two experimental programs together with companion numerical studies that were carried out on reinforced concrete shear walls: static tests and dynamic (shake table) tests.
The first series of experiments were monotonic and cyclic quasi-static testing on ductile reinforced concrete shear wall specimens designed and detailed according to the seismic provisions of NBCC 2005 and CSA-A23.3-04 standard. The tests were carried out on full-scale and 1:2.37 reduced scale wall specimens to evaluate the seismic design provisions and similitude law and determine the appropriate scaling factor that could be applied for further studies such as dynamic tests. Ductile flexural response was observed under cyclic loading up to a displacement ductility of 4.0. At this deformation level, inelastic shear deformations in the plastic hinge contributed to approximately 20% of the total lateral deformation. In the subsequent cycles, strength degradation took place due to shear sliding developing along the large flexural cracks at the wall base. Comparisons of the test results between prototype and reduced scale walls showed excellent agreement, which proved that using of scaling factor around 2.3 for the model wall could adequately predict the inelastic responses of prototype reinforced concrete shear walls
Past numerical simulations performed by previous researchers have shown that higher mode response can be significant for high-rise reinforced concrete shear walls used in building structures to resist lateral loads, when subjected to ground motions rich in high frequency that are expected in earthquakes occurring in Eastern North America. Higher mode response can lead to the development of plastic hinges in the upper portion of walls, in addition to the base plastic
hinge assumed in design according to current codes and design standards. Higher mode effects can also result in significant dynamic shear amplification at the base of walls, in excess of the shear resistance prescribed in current code documents. Experimental testing was needed on reinforced concrete walls under Eastern North America earthquake motions to validate these higher mode effects predicted by numerical simulations. This thesis presents two experimental programs together with companion numerical studies that were carried out on reinforced concrete shear walls: static tests and dynamic (shake table) tests.
The first series of experiments were monotonic and cyclic quasi-static testing on ductile reinforced concrete shear wall specimens designed and detailed according to the seismic provisions of NBCC 2005 and CSA-A23.3-04 standard. The tests were carried out on full-scale and 1:2.37 reduced scale wall specimens to evaluate the seismic design provisions and similitude law and determine the appropriate scaling factor that could be applied for further studies such as dynamic tests. Ductile flexural response was observed under cyclic loading up to a displacement ductility of 4.0. At this deformation level, inelastic shear deformations in the plastic hinge contributed to approximately 20% of the total lateral deformation. In the subsequent cycles, strength degradation took place due to shear sliding developing along the large flexural cracks at the wall base. Comparisons of the test results between prototype and reduced scale walls showed excellent agreement, which proved that using of scaling factor around 2.3 for the model wall could adequately predict the inelastic responses of prototype reinforced concrete shear walls
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