Computer-Aided Structural Engineering (CASE) Project. User's Guide: Computer Program for the Design and Investigation of Horizontally Framed Miter Gates Using the Load and Resistance Factor Design Criteria (CMITERW-LRFD) Windows Version.

Lock gates serve several different functions, depending on locations and conditions. The major use of lock gates is to form a damming surface across a lock chamber, but the gates may also be used to serve as guard gates, to fill and empty a lock chamber, to allow ice and debris to pass, and to provide access from one lock wall to the other by means of walkways or bridgeways installed on top of the gates. A navigation lock requires closure gates at both ends of the lock so the water level in the lock chamber can be varied to coincide with that in the upper and lower approach channels. Many locks in the United States are equipped with double-leaf miter gates that are used for moderate- and high-lift locks, having a height of 20 to 80 ft and a chamber width of 56 to 110 ft. These gates are fairly simple in construction and operation and can be opened or closed more rapidly than any other type of gate. Maintenance costs are generally low. Miter gates are framed either horizontally or vertically. The skin plate of a horizontally framed gate is supported by horizontal members that may be either circular arches or straight girders acting as beams. Each horizontal member is supported by a vertical quoin post at one end and a miter post at the other (Figures 1-3). A vertically framed gate resists water pressure by use of a skin plate supported on a series of vertical girders almost uniformly spaced along the length of the gate. The vertical girders are supported at the top and bottom by horizontal girders that transmit the loads to miter and quoin at the top of the leaf and directly to the sill at the bottom (Figure 4). Due to the greater rigidity and resistance to boat impact of the horizontally framed miter gates and the insignificant difference in cost, vertically framed gates are no longer designed by the U.S. Army Corps of Engineers (USACE) except in unusual applicat