Browsing by Author "Mhando, S. K"

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    Analysis of ring beam foundation using matrix method on PC
    (University of Dar es Salaam, 1991) Mhando, S. K
    Ring foundation problem is known to have engineering significance and has extended to water-tower structures, transmission towers, TV antennas, radar bases and various other structures. In view of the fact that the analysis by means of numerical methods such as Finite Element Method (FEM) can now be carried out on Micro Computers without much restrictions, definitely warrants the pursuance of the proposed study effort. The study will not only facilitate use of an improved analysis program written in one of the high level languages but also the information contained will shed some additional light on the usefulness of the adopted model tested. The model considers analysis of a finely discretised closed ring resting on an elastic subgrade, the so called Winkler medium. The finite elements are approximated to a straight line element model in contradistinction to an exact solution of the curved geometry of the elements. The study also compares solution of an element on an approximate representation of elastic subgrade by nodal springs with that of an element on a response of a continuous elastic subgrade. The results of this study have explicitly been presented in parametric manner and they form the basis for conclusions and recommendations. It has been a necessity to present results that way in order to facilitate comprehension and evaluation of a composite influence of inter-related parameters on the ultimate behaviour of such a ring resting on an elastic medium. In this study, a limit case of a ring on a very weak subgrade (4 = 0) loaded by vertical nodal loads has been considered. In this particular case the nodal loads are considered as rigid supports and the subgrade response as a uniformly distributed load acting on the ring. Herein, the solution of this system has been used for comparison purposes and as a check to the accuracy of the RING7 program within the limit psi values where the RING7 solution is identical or can be approximated by this approach.