An Evaluation of Uplifting Behavior of Container Cranes Under Strong Earthquakes.

Abstract

Uplifting of legs of container cranes is often observed in strong earthquakes, and assumed to be one of the main causes of their structural damage. However, strong nonlinearity of such behavior has prevented us from taking it into consideration in the design of container cranes. Therefore, in order to develop a method to simulate the behavior, we carried out finite element analyses and excitation tests on a 1/25 scale model of a container crane. Comparing those results, we proved that nonlinear finite element method with gap elements is an effective method to simulate the uplifting behavior. Furthermore, we carried out finite element analyses on an actual container crane. Those result showed that the deformation of legs due to uplifting is a cause of structural damage, as actually seen in the Hyogoken Nanbu Earthquake.