Miter‐Type Navigation Lock Gates

Abstract

A theoretical analysis for a horizontally framed miter‐type lock gate structure under hydrostatic pressure is presented. A set of nonlinear equations for failure modes of mitered gates is derived by the variational method incorporated with Lagrange multiplier to account for a constraint condition. The unique solution on the load‐deflection curves indicates that there is no other type of buckling mode than snap‐through when the mitered angle is very large. For mitered angle not so large, the failure mode is governed by the flexural yield stress at the center of the gate girder. The result is compared with AISC beamcolumn formula upon which the current design is based. Good agreement is reached if the failure mode is governed by the maximum flexural stress, and thus the beam‐column treatment is justified for practical purposes. Forces in such case can be directly obtained by equilibrium method, and deformation effect can be neglected. For very large angle, however, snap‐through buckling may control the capacity, and the deformation effect considerably reduces the capacity.