Seismic behavior of unbonded post-tensioned precast concrete members with thin rubber layers at the jointed connection
The use of precast concrete members with jointed connections for seismic applications has gained momentum recently; however, these systems may have limited application in seismic regions. This is because their dominant mechanism of impact damping is considered to be inadequate to dissipate the seismic energy imparted to them. With no hysteresis elements, precast concrete members with jointed connections may undergo long durations of motion and large lateral drifts when subjected to seismic loads. This paper investigates a method that can allow these members to dissipate the seismic energy efficiently by having them rock on a thin rubber layer that is placed at the jointed connection. Experiments that examine the use of various classes and layer thicknesses of rubber show that this method can improve damping in these members. Using experimental and numerical data, this paper quantifies the energy dissipation and seismic responses associated with this use of rubber. It is shown that rubber layers with high shore hardness of 90 and thickness between 6.35 and 25.4 mm (0.25 and 1 in.) improve the amount of damping in lateral-load-resisting systems using precast concrete members and produce satisfactory seismic response for these systems.