Displacement ductility and energy assessment from shaking table tests on RC structural walls

Dynamic tests on six reinforced concrete structural walls on the ETH earthquake simulator have generated many new opportunities for the assessment of seismic behavior and energy. After a brief outline of the tests, this paper describes an investigation involving an experimental determination of yield displacement, displacement ductility, and energy content of the walls during the tests. Yield displacement is directly obtained from measurements. The measured results correspond well to calculated predictions. Moreover, displacement ductilities reached during the tests coincide with the design assumptions. Input, kinetic and dissipated energies (through friction, viscous damping, and plastic deformations) are also determined from measurements. Variations in the distribution of the energy dissipated by plastic deformations (hysteretic energy) at the wall bases are related to the good and poor seismic behavior of the walls as observed during the tests. If energy dissipation is concentrated at the first crack at the wall base, it leads to poor seismic behavior. The ratio of hysteretic energy to the total dissipated energy (friction + viscous + hysteretic) remains almost constant.