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To assist crane operations planners and others to assess the risk of overturning in crane operations, consideration is given to the action of a short duration dynamic force on a generalized free standing crane loaded with a system of static overturning and stabilizing forces. An equation has been developed to reflect an equivalent dynamic moment for comparison with the static moments acting on a crane. A rule is found that combines into one overturning moment the effects resulting from two or more simultaneous impulses induced by several crane mechanisms. It is shown how crane or installation parameters can be altered to reduce and control overturning risk in crane operations, and how accident investigators can achieve a realistic appreciation of dynamic episodes.

In some box section cantilevered booms, the assumption of simply supported edges for the compression plate is too conservative. A method is provided here for readily determining, from section dimensions, when better edge restraint conditions are present. Equations are provided for calculating edge restraint factors and for increasing the effective compression plate width when appropriate.