Numerical Investigation of Diagonals in Miter Gates: Looking for the Optimum Prestressing

This article presents a proposed methodology to acquire optimum prestressing on diagonals in miter gates. The study uses three-dimensional (3D) numerical simulation of miter gates that includes all the geometrical details of the most commonly used miter gates. The simulation is used to attain vertical and lateral displacements at the miter end when the gate is mitered and in the operation for different prestressing forces. The simulation results allow the development of design curves that are used to obtain the optimum prestressing loading. These design curves can also be used to verify that the displacements of a gate are within tolerances for existing levels of prestressing. The analyses are compared with the existing criteria. The comparison shows that the miter gate leaf is not limited to only one prestressing combination, as prescribed by the design criteria, but several prestressing combinations evaluated from the numerical experiments can also provide the adequate torsional capacity. Furthermore, the study shows that the design criteria estimates a higher prestressing that likely causes a reduction in fatigue life in the diagonal connections. The new techniques will allow the prediction of optimum prestressing levels without compromising the torsional capacity.