TT Club highlights the vulnerability of quay cranes, other handling equipment and containers to major weather related incidents at marine terminals, commenting that it is a common phenomenon of cranes to be blown along the crane rails.
According to the Club’s analysis, equipment and property damage incidents in container terminals continue to feature in the industry trade press all too frequently.
While a number of these involve third party impacts, and some relate to lack of maintenance or improper procedures, a prevalent factor is the exposure to windstorms. The ship-to-shore or quay crane is one of the most valuable assets of a marine terminal in terms of cost and operational dependence.
Quay cranes are vulnerable to wind
Because of their size, profile and location on the quayside, quay cranes are particularly susceptible to wind, and care must be taken in the design and operating procedures to protect the asset.
These kinds of incident can lead to serious injuries to workers and, particularly when quay cranes are involved, can be very costly in repairs and operational downtime. The impact of windstorms can be mitigated by having appropriate procedures in place and ensuring that they are followed. Essential elements include having effective national and local weather reporting systems and ensuring that operational procedures respond effectively when sufficient warning is forthcoming.
In addition, it is advised that empty containers should be cautiously located in areas safe from windstorms. In certain locations there may be capacity challenges, but due consideration should be given to the planned profile of stacks, specifically the height and depth. Stacks should be aligned so that the units’ longitudinal axes are in line with the predominant wind direction. In advance of forecast storm conditions, particularly where stack heights cannot be reduced, additional measures could include interlinking with locking cones, straps or webbing to create a heavier and more stable mass.
Where stacks are more than four high, consider a ‘pyramid’ formation
… TT Club recommends.
#1 Storm pin and tie-down facilities and procedures are invoked.
It is stated that well designed and maintained braking systems, can significantly help in conditions of sudden wind microbursts. There are two primary windstorm issues to be considered: protection against forecast strong winds and protection against sudden local winds called microbursts.
#2 Operators should recognize the changes and where appropriate re-assess the risks accordingly.
#3 Consider retrofitting storm pins and tie-downs for existing cranes.
Are the average and peak wind speeds now higher than the wind speeds used for the maximum uplift calculations during initial design?
While forecast storms clearly present risks, the occurrence of microbursts, during which even the maximum forecast wind speed may be exceeded, create an additional and ongoing challenge. In the worst circumstances, unknown to the driver, a strong wind might arise, blowing in the same direction that the crane is travelling and the driver is unable to keep control. To deal with such situations, suitable storm brakes and service brakes are necessary. These are not, however, an acceptable alternative to pins or tie-downs for forecast windstorms.
#4 Particular care should be taken where quay cranes have had their legs raised and/or booms extended; wind and uplift calculations should have been performed at the time of modification to ensure existing storm tie-downs and civil works were structurally adequate.
Review may be necessary to consider whether further changes are appropriate.