A comparative study on application of design codes for prediction of fatigue life of a mining dragline cluster

Mining dragline booms are possibly the most severely fatigue loaded structures in industrial use. These booms swing from side to side under high acceleration and deceleration about once every minute and thus experience very large fatigue cycles. Unlike many other structures, mining dragline booms are deliberately loaded until they crack. The reason for this is the economics: there is a high value placed on the loads and the frequency of their movement. This paper presents a comparative study on the application of several existing design codes for prediction of the fatigue life of a typical four-member dragline cluster in a BE 1370 boom. The paper concludes that the current design codes applicable to such welded structures provide very conservative results, which if used on these mining booms would result in much thicker and heavier structures.