Dynamic Ductility Demand and Capacity Design of Earthquake-Resistant Reinforced Concrete Walls
H. Bachmann and P. Linde
Appears on pages(s):
capacity; ductility; earthquake-resistant structures; hysteresis; flexural strength; dynamic structural analysis; reinforced concrete; standards; stiffness; strength; structural analysis; structural design; walls; Design
Reinforced concrete structural walls may provide efficient earthquake resistance in multistory buildings. In Europe, they are commonly combined with gravity load dominated slender columns in which the entire horizontal action is taken by the walls. In recent years, it became possible to design reinforced concrete structural walls in a clear manner according to the capacity design method which is based on an "elastic" equivalent static force reduced by a global displacement ductility factor and by an overstrength reduction factor. In this paper, a nonlinear dynamic performance check of capacity designed walls was carried out. For this purpose, a newly developed macro model was used for the modelling of the wall. Nonlinear time history analyses were carried out with a ground motion compatible to the elastic design response spectrum of the Swiss Standard SIA 160 as input. The major findings of this paper pertain to three important design aspects as follows. 1. The dynamic rotational ductility demand may have a different distribution over various height to length aspect ratios of the wall than previously anticipated by static analysis. 2. The dynamic bending moment demand over the height of the wall may differ from the static assumption depending on the aspect ratio of the wall. This necessitates a modified moment capacity distribution. 3. The dynamic shear force at the base of the wall may exceed the previous assumptions of the capacity design method.