FLUID - STRUCTURE INTERACTION IN A BARRAGE

Abstract

Interaction problems involving two or more disciplines are often encountered in most of the engineering practices. One of such interactive disciplines is the so called Fluid - Structure interaction. In the present work a barrage consisting of five bays is considered to study the influence of fluid pressure on the behaviour of structural components such as raft and pier under dynamic condition using finite element method. Zanger's formula for hydrodynamic pressure is used to take into account the fluid interaction with the structure. The Finite Element package, ANSYS has been used to carry out the analysis. The barrage is located partly on soil and partly on rock. The barrage has been analyzed considering a total of three models considering each model as a individual structure. Modeling of barrage is done using 2D Plane42 elements (4 noded quadrilateral elements) and 3D Solid45 elements (8 noded brick elementsliffirrirTfrfftliftl• been carried out to find out the time periods and mode shapes .considering stiffness of the soil and mass and stiffness of the structure. Seismic analysis of the Barrage has been carried out using the response spectra of the site under different combination of seismic excitation with and without fluid-structure interaction. The study points out that the time periods obtained from fluid-structure interaction are higher than the time periods without fluid-structure interaction. Also the stresses and displacements in raft and pier are considerably on higher side when fluid-structure interaction is considered. Various points of the study illustrate the importance of fluid-structure interaction in barrages.