Seismic Guidelines for Cranes

by Erik Soderberg, Jonathan Hsieh, and Anna Dix
Presented by Erik Soderberg at the TCLEE 2009 Conference in Oakland, California

Current large cranes with 100 foot rail gages are much heavier, which results in significantly larger seismic forces in the crane structure. Our studies indicate that many jumbo cranes will be extensively damaged in moderate earthquakes, and many jumbo cranes will be severely damaged, or collapse, in the contingency level design earthquake.

Our presentation suggests some approaches to evaluate what seismic risk is tolerable to existing cranes and some guidelines on what structural characteristics increase or decrease the seismic risk, along with suggested practical retrofit options including strengthening, stiffening, and adding a base isolation mechanism that can limit the seismic forces.