Investigation of the dynamic loads on tower cranes during slewing operations

For decades, tower cranes have been the most important hoisting device used in building construction. In order to avoid security risks at the construction site, it is essential to analyse the dynamic behaviour of these cranes during the work process as the crane motions cause dynamic forces on the supporting structure. According to the current standards, stress calculations for tower cranes are carried out based on static approaches. The standards stipulate the use of special dynamic factors in the static calculation to estimate the dynamic loads. This article analyses the dynamic behaviour of a tower crane during the important work process of slewing. The results of the approach according to the standards are compared with the results of the nonlinear dynamic finite element calculation. In addition, a newly developed vibration model based on a two-mass model will be presented in this paper. The model helps to estimate the dynamic loads more accurately than the methods currently used. However, the computation time required to perform the stress calculation is only slightly increased.