Non-linear FEM analysis of earthquake-induced pounding between the main building and the stairway tower of the Olive View Hospital

The reports after major ground motions indicate that earthquake-induced pounding between buildings may lead to substantial damage or even collapse of colliding structures. The research on structural pounding during earthquakes has been recently much advanced, although most of the studies were conducted on much simplified discrete lumped mass models of buildings. In the present paper, a detailed three-dimensional pounding-involved response analysis of two adjacent structures has been conducted using the FEM with the non-linear model of material behaviour, including stiffness degradation of concrete under cyclic loading. The study concerns pounding between the Olive View Hospital main building and one of its independently standing stairway towers, which was observed during the San Fernando earthquake of 1971. The results of the study show that collisions may lead to a significant increase of the response of the lighter stairway tower as well as may result in a substantial increase of the range and intensity of damage at the base of the structure, whereas the behaviour of the heavier main building has been found to be only slightly influenced by structural interactions. The results clearly confirm that special attention should be paid to appropriate design of a weaker building, for which earthquake-induced structural pounding can be catastrophic.