Click the link to view a video of a seismic loading experiment. The reinforced concrete column was subjected to a constant vertical load, simulating the gravity load, while increasing cyclic lateral displacements were imposed. The loading apparatus restrains the rotation of the upper beam thus putting the column into double curvature.
Using software developed by FSEL engineering staff, the video has been synchronized with the plot of the lateral load-displacement curve. The experiment can be examined in detail by moving the slider at the bottom of the video.
(The video file is fairly large, so it may take a little while to load.)