The measurement of vertical and lateral forces on electric overhead cranes during operation.

Abstract

This dissertation is a practical investigation into the magnitude of the vertical and lateral forces exerted, by electric overhead travelling cranes, on their supporting structures during operation. The method of measuring the forces and the equipment used for the actual measurements are discussed, as well as the equipment used for the processing of the recoided date. The forces measured during the experiments, executed in two stages namely controlled conditions and normal operation, are discussed under the headings of vertical forces due to the weight of the crane and lead handled, and the lateral forces due to cross travel movement, skewing of the crane and acceleration/deceleration of the crane. It is shown that the vertical misalignment of the rails, together with the stiffness of the crane structure, has a large influence on the magnitude of the vertical forces. Drive wheel slip, tested under controlled conditions on two E-type cranes, proved to cause high lateral forces. Comparisons are made with the existing Codes of Practice as well as with the theoretical models of crane behaviour.