The Impact of Jumbo Cranes on Wharves

Worldwide container traffic continues to grow faster than the worldwide economy. Increased traffic means increased ship size and terminal throughput. Ship size and production demands lead to bigger and faster cranes: cranes capable of serving 22-wide ships and lifting 65 metric tons under spreader and 100 metric tons under hook. These new jumbo cranes are imposing greater loads on the wharf structure, loads that wharf designers are just now beginning to realize. The jumbo cranes are big: 65-m outreach, 37-m lift height, increased wind area, and increased weight and inertia forces. Their designs are affected by trolley type, maintenance needs, automation, and trolley and hoist speeds. Even their power requirements are changing. These factors result in heavier wheel loads, greater stowage and tie-down forces, and increased collision bumper loads, creating the need for stronger wharves. Even though the overall wharf design doesn't change much for these cranes, the designer needs to look at the capacities of the rail girders, the stowage devices, and the collision bumper. Stowage pin sockets and tie-down brackets are key elements in the wharf that often get overlooked. More cranes are damaged from the failure of the connection in the wharf during high winds than from the failure of the crane itself. This paper presents current design issues for jumbo cranes and discusses how they effect wharves.