Nonlinear dynamic analysis of arch dams considering contraction joints

Abstract

Arch dams are massive plain concrete structure, their stability and security are usually controlled by the tensile behavior and cracking of concrete. They are constructed as vertical monolithic cantilever elements separated by contraction joints filled with mortar. This contribution consists of the evaluation of the performance and the reliability of nonlinear joints numerical models used in the finite element open source code “Code-Aster.” These contraction joints can only transfer limited tensile stresses between the adjacent cantilever monoliths. Relative motions of the cantilever monoliths during an earthquake induce the opening, closing, and sliding of the contraction joints, resulting in significant dissipation of the seismic input energy. For these reasons, Nonlinear Time History Analysis is carried out in order to locate and estimate the probable damages of the structure in the form of joints opening. The numerical results obtained from nonlinear time history analysis show that the contraction joints opening releases the tensile stresses in the arch, but increases the compressive stresses in the arch and the vertical stresses in the cantilevers. The increase in the compressive stresses in the arch can lead to the crushing of the concrete, and to the increase of vertical stresses in the cantilevers which can exceed the tensile strength of the concrete arch, resulting in the apparition of tensile cracks along the horizontal joints. High tensile stresses may also appear along the Dam–Rock interface causing cracks along the contact surface.