Behavior of metal linings

Abstract

1. The characteristic damage to steel linings is fracture due to metal fatigue in flexing, which is possible when the lining is not flush against the concrete. 2. Steel linings should not be used in pressure and free-flow conduits operating at part flow, in particular in the draft tubes of hydroelectric stations where the flow velocities and the energy of the stream are low. Also, the torn-away lining should not be restored. When repairing it suffices to the patch the damage with cement or epoxy resin [4]. There is no need either to place a steel lining in spiral casings at heads up to 60 m. In place of steel linings in these cases one should use high grades of monolithic concrete (M-300, M-400) and take special measures to impart to the surfaces extra smoothness and to increase imperviousness. 3. In the turbine runner chambers it is necessary to install steel linings to impart and preserve the prescribed shape. Here the use of cast steel linings at least 18–20 mm thick is warranted. 4. When constructing steel linings particular attention should be given to anchorage to the concrete by installing stiffeners, etc., and also to very careful concreting to avoid the formation of pits and cavities behind the lining. 5. Steel linings should be regarded as plates or cylindrical shells supported about the contour with a magnitude of deflection not exceeding about 0.001 of the span. 6. The use of steel-concrete linings should be avoided since they are subject to faster wear than concrete linings.