FEM ANALYSIS OF A BARRAGE UNDER VARYING SUBSOIL CONDITION

Abstract

The objective of this dissertation is the Finite element analysis of a barrage under varying subsoil conditions under the influence of static and seismic loads. The finite element package, ANSYS is used to carry out the various analysis. The barrage consider for analysis is consisting of five bays. It is located partly on soil and partly on rock. There being construction joint between bays in the transverse direction. So the barrage has been divided into three substructures consisting of bay 5,bays 3&4 and bays 1&2. The barrage has been modeled using 3D 8 node brick type of element. Relevant amount of soil around the barrage has also been modeled to find out the effect on the soil. Static analysis of the barrage has been carried out considering significant dead loads. Free vibration analysis has been done to find out the natural frequencies and mode shapes considering both the stiffness of the soil and also mass and stiffness of the soil. Seismic analysis of the barrage has been done using the response spectra of the site by giving excitation in longitudinal and transverse direction respectively. The study indicates that it is preferable to avoid such type of site where there is varying subsoil condition as there is a possibility of development of tensile stresses in the structure. Further, soil treatment may be necessary for such barrage locations