Water-Filled Bladders, an Innovative Bearing Interface for Arch Dam Bracing

Some existing arch dams can require the construction of a supporting downstream structure to improve their behavior. The bracing structure is generally rigidly connected to the dam, but in some cases the designer can seek a flexible connection that can adapt to the deformation mode of each structure and avoid hard points emergence and stress concentration. This has already been done at Kölnbrein dam in Austria, by the use of rubber pads. The paper presents a new solution to realize a flexible connection, allowing an excellent control of the forces transferred from the dam to its bracing structure. The solution relies on large inflatable jacks hydraulically connected to the reservoir. This EDF-patented solution also affords the distinct advantage of not requiring unloading the dam in order to load the bearings. This solution, based on the use of water-filled bladders, is under development at detailed design stage for a 50 m high arch dam. Some tests will be conducted at the end of 2017 on full scale prototypes (4 m x 11 m x 0,8 m), with a dedicated vertical test bench, in order to qualify bladders’ suppliers and check the installation and filling process of the bladders.