02-08-2013, 10:44 PM
Seismic Demands in High Rise Concrete Walls
Author: Timothy Watkins White | Size: 15.19 MB | Format: PDF | Quality: Unspecified | Publisher: Timothy Watkins White | Year: 2006 | pages: 319
Concrete walls are the seismic-force-resisting system of choice for high-rise buildings on
the west coast of Canada, and they are becoming an increasingly popular system in other
seismically active regions of the world.
A concrete wall system dissipates energy during earthquakes by forming inelastic
mechanisms at the base, and in the coupling beams (for coupled walls). For this to occur
in a safe and controlled manner, the inelastic rotational demand on the walls and the
coupling beams must not exceed the inelastic rotational capacities of these elements.
The inelastic rotational demand on a concrete wall or coupling beam can be determined
using non-linear dynamic analysis; however simplified methods are preferable for design.
Axial forces are developed in the wall piers of a coupled wall system when shear
forces are transferred from the coupling beams. The Canadian Concrete Code A23.3-94
requires the factored resistance of the wall piers in axial tension be greater than or equal
to the sum of the nominal shear strengths of the coupling beams. While this certainly
applies to short walls, it is a matter of debate as to whether it should also be applied to
high-rise walls. Additionally, it is not known how the performance of coupled walls is
affected if the walls do yield in axial tension. Allowing for a reduction in the tension
capacity for tall coupled walls would allow for a more cost-effective design.
In this study, simple and rational procedures are developed to estimate the
inelastic rotational demand of concrete walls, and the maximum total coupling beam
chord rotation and, the performance of concrete walls with axial yielding is assessed.
These findings were derived on an understanding of the behaviour of concrete walls,
based on the results from numerous dynamic analyses.
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