A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Engineering and Technology

Thesis (M.Eng.) - Asian Institute of Technology, 1985

An improved solution scheme is presented for vertical vibrations of a circular footing resting on, or partially embedded in, a homogeneous elastic half space. The semi-infinite medium is partitioned into a near field and a far field. The near field, which consists of the footing and a finite region of elastic continua around it, is modelled by conventional finite elements. The far field is modelled by infinite elements. The method falls within the framework of the classical finite element technique and preserves its flexibilities. An existing radial element algorithm is improved and an axisymmetric horizontal infinite element capable of propagating pressure, shear and Rayleigh waves in semi infinite media, is developed. By using infinite elements, the size of the near field may be kept small which provides the analyst an inexpensive solution. The method is successfully applied to find the vertical compliance functions of semi infinite media subjected to harmonic surface loads and a rigid plate subjected to harmonic loading on semi infinite media. Further the elastodynamic load transfer problem of a cylinder partially embedded in and elastic half space is investigated.