Optimal Design of Horizontally Framed Miter Gates

Miter gates have been, and still are, widely used in hydraulic engineering as control devices for several types of locks (e.g., navigation, flood, tidal, etc). Since centuries, engineering practice suggests a range of optimal values for the angle that the gate leaves must form pointing upstream, facing the current. According to experience and literature, this optimal range corresponds to an angle between the leaf and the normal to the lock wall that varies between 9.5° and 33.7°. It is confirmed here that in horizontally framed miter gates, which is the most usual arrangement, these optimal values depend only on the lock dimensions (span and height) and the geometric characteristics of the girder cross-section. Using a simple dimensionless geometrical parameterization and static equilibrium considerations, a general approach for the preliminary dimensioning of miter gate leaves is developed, based on the optimization of the angle between the leaves for the three most commonly used types of girder cross-section: square, rectangular, and “I-beam” (IPE series).