by Brianna Crandall — September 9, 2016 — A new standard from the International Organization for Standardization (ISO) for cranes used in seismically active regions was developed to ensure that this equipment often seen towering over city landscapes does not pose a risk by collapsing during an earthquake. ISO 11031 can be used to calculate seismic loads, and sets out design principles for cranes destined to work in seismically active regions and for cranes required to be earthquake-resistant.
A new ISO standard for cranes used in seismically active regions was developed to ensure that this equipment often seen towering over city landscapes does not pose a risk by collapsing during an earthquake.
Klaus Pokorny, secretary of the ISO subcommittee working on design principles and requirements for earthquake-resistant cranes, explains, “To make sure that cranes are safe, we first need to calculate the seismic loads that show how a crane will respond in moderate to severe earthquakes. Then you can use design limit states provided in two forms: serviceability limit and ultimate limit.
“The serviceability limit state (SLS) ensures that the crane can withstand the effects of moderate earthquake ground motions throughout its service lifetime and continue to operate as intended. The ultimate limit state (ULS) requires that the crane structure should not collapse during severe earthquake ground motions, and that the suspended load or any other part of the crane should not fall or harm the public, operators and workers.
“Any evaluation should take into account the regional seismic conditions as well as the ground surface conditions at the crane location. It’s also important to consider how the crane will be used and any risks that could result from seismic damage.
“Not only will ISO 11031 add a layer of confidence to the industry, it also provides a common technical language so that manufacturers, users and owners understand each other clearly, no matter where they are — a boost for global trade.”
ISO 11031:2016 Cranes — Principles for Seismically Resistant Design, available from ISO, was developed at the request of Japan, which, following the 1995 earthquake in Kobe, emphasized the need for a standard to ensure earthquake-resistant cranes. The secretariat of the subcommittee that developed the standard is held by DIN, the ISO member for Germany.
