International Journal of Engineering and Technology

The spiral case of a hydro-turbine is embedded in concrete to transmit the loads of the generating units and ancillary equipments over it to the foundation. The surrounding concrete also acts as a shield to the steel spiral case and restricts its deformation. The stresses and deformations at different locations inside concrete around spiral casing of a hydro-turbine, subjected to static loads of the generators and other structures above it, are worked out using Finite Element Method (FEM), and presented in this paper. A 3-D model is considered as per the dimensions of the physical model tested by Nigam [1]. Total static load acting on the spiral case is applied uniformly on the concrete surface spreading over an annular area encircling the turbine pit to determine the normal stresses and deformations in the concrete. The results obtained by the FEM model are compared with those obtained by Nigam through photo-elastic method, which is an experimental one. Nigam’s study revealed only the normal stresses in the concrete. But in the present study in addition to the above, deformations along different axes and shear stresses in separate planes are also computed. The ANSYS CAE software is used in conjunction with 3D CAD solid geometry to simulate the behavior of the structure under various loading conditions, and to generate the results. A comparative study results are presented in this paper.