Two-dimensional elastica analysis of equilibrium shapes of single-anchor inflatable dams

Several types of inflatable dams are considered. These are long, air-inflat ed, cylindrical structures on a rigid foundation. Sometimes one of the long edges of a sheet is folded back to the other edge, and then the two edges are clamped to the foundation along a single anchoring line. A second confi guration can be modeled as two sheets attached along two long edges, with o ne edge anchored and the other free to lift as air pressure is applied betw een the sheets. Another device treated here is a hinged spillway gate lifte d by an inflatable bladder. The cross section of the dam or bladder is anal yzed as an inextensible elastica. The governing equations and boundary cond itions are formulated for each case, and shooting methods are utilized to o btain numerical solutions for the equilibrium shapes. The effects of the in ternal air pressure and the external water height are investigated. (C) 199 8 Elsevier Science Ltd. All rights reserved.