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Title: The distribution of concrete stress in pre-stressed and reinforced concrete beams subjected to pure flexure
Author: Prentis, James Martin
Awarding Body: University of London
Current Institution: Imperial College London
Date of Award: 1954
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The object of this thesis is to consider the problem of determining the distribution of compressive stress in a reinforced or pre-stressed concrete beam subjected to a pure bending moment at loads approaching the ultimate. The attainment of this object is desirable because the full development of an ultimate load theory for prestressed concrete appears to depend upon it. It is pointed out in the concluding chapter that this reason is debatable and indeed that the ultimate load theories themselves are at present the subject of controversy. These matters are deemed to be outside the scope of this thesis which concerns itself solely with the object stated above. The thesis starts with a study of the normal, assumptions of concrete design. It then goes on to survey the possible methods of measuring directly the stresses in a concrete beam particularly under plastic conditions. A method developed by the author for determining these stresses indirectly is then introduced. After careful study of the validity of this method it is applied to results of tests on a number of beams. Return is then made to one of the basic assumptions of ordinary (’elastic’) concrete design. An analysis is made of the effect of finite spacing of tensile cracks on the distribution of compressive stress (normally it is assumed to have no effect). An investigation is also made of the effect of end friction on the stress distribution in a. cube. The object of this study is to see whether stress-strain readings taken in such a test have any significance for the same concrete used in a beam.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available