Experimental Determination of the Seismic Response of Port Container Cranes Including Uplift Phenomena

Abstract

Increased container shipping has lead to larger, more complex cranes to serve the ever-larger ships. The increased size and mass of modern container cranes makes them potentially more seismically vulnerable then their smaller predecessors. Container cranes are essential to the operation of a port, and the economic impact from their downtime can be substantial. In order to better understand the seismic vulnerability of modern container cranes, shake table experiments are conducted on a 1:20 scale model of a typical container crane found in the ports on the west coast of the United States of America. During previous seismic events, three main failures were observed: derailment, where the wheels lift up off the rails; local buckling of the legs; and collapse of the crane. During this study, the focus was on derailment and the uplift/pounding phenomenon associated with it. In order to better understand uplift and derailment, a 1:20 scale model is constructed. The model is designed such that the members would remain elastic during design earthquakes. The model crane is tested on a six-degree-of-freedom shake table at the University at Buffalo. The movements of the legs are tracked and strains in the sections of the crane that were determined to be vulnerable by the analyses were measured. The results of the study are presented in this paper.