With damaging hurricanes in the Atlantic, typhoons and cyclones in the Pacific, monsoons in the Indian, and random windstorms occuring anywhere, port equipment, premises and liability insurer, TT Club is strongly recommending that terminal operators urgently review their terminal emergency plans for dealing with high winds and in particular crane tie-down procedures.
Wind damage Analysis of the TT Club’s claims over a number of years has highlighted that wind damage to quayside cranes is the biggest weather related cost to terminals. Commonly, this damage is caused by quayside cranes being blown over or blown along the crane rails.
Due to their size, profile and location on the quayside, these cranes are particularly susceptible to wind, and care must be taken in the design and operating procedures to protect against damage.
“This type of incident can result in serious injuries to workers and be very costly in repairs and operational downtime,” notes Laurence Jones, TT Club’s Director Global Risk Assessment. However such incidents can be prevented, or at least the collateral damage caused can be restricted by having appropriate procedures and ensur ing 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, good practice would dictate that storm pin or tiedown facilities and procedures are invoked. Furthermore, better designed braking systems, which are properly maintained, can significantly help in conditions of sudden wind micro-bursts. There are two major windstorm issues to be considered: protection against forecast strong winds, and protection against sudden local winds called micro-bursts.
In the case of forecast strong winds, storm pins and tie-downs of sufficient number and size to hold a crane structure stationary (and procedures to implement these) are required to protect quayside cranes. Storm pins are vertical sliding pins mounted at suitable positions under each leg of the crane. These pins are dropped into sockets set into the surface of the berth. The pins must be interlocked with the travel motion so that the crane can only be moved when the pins are disengaged.
Storm tie-downs are connections on the crane, normally at the four corners, where suitable slings, chains or bars of appropriate size and number are fitted to connect to anchor points in the terminal pavement. These anchors must be able to hold the loadings of the crane under potential wind conditions.
The other situation of primary danger is the occurrence of micro-bursts. In the worst circumstances, unknown to the driver, a strong wind arises blowing in the same direction in which the crane is traveling and the driver is unable to stop. To deal with these situations, suitable storm brakes and service brakes are necessary and should be fitted to the crane. These are not however, an acceptable alternative to pins or tie-downs for forecast weather conditions.
There are a number of different systems used for storm brakes or, as they are sometimes called, parking brakes. These include rail clamps and railhead brakes. However, these are static brakes, i.e. they are only applied when the crane has stopped moving. They normally operate if the emergency stop is activated and unless severely damaged will help prevent a stationary crane from being pushed along by the wind. Their main purpose and benefit is to park and anchor the crane between normal operations without the need to apply the storm pins or tie-downs.
If rail clamp and railhead brakes are applied when the crane is moving, both the brakes themselves and the crane rail can be damaged. For this reason, wheel brakes should also be installed; these are normally disc brakes mounted on the crane wheels. Finally, the service braking system forms the normal operating brake. This is part of the motor and gearbox of the crane, which slows and ultimately stops the crane during daily working.