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Title: An experimental study of the strength of thin isolated column base in reinforced concrete
Author: Marshall, W. T.
Awarding Body: University of London
Current Institution: Imperial College London
Date of Award: 1939
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The object of the research described in this thesis was to determine the usefulness of the regulation limiting the punching shear in an isolated column base. The tests were carried out on thin bases as the punching shear stresses are greatest in thin sections. The thesis is divided into three parts giving, 1) a survey of methods of design of isolated column bases, 2) tests on bases founded on different soils, and 3) tests on bases with varying percentages of reinforcement* Part I in addition to the standard methods of design also shows the application of Westergaard's methods and discusses the various theories for the distribution of pressure beneath a column base. Part II describes a series of tests carried out on thin bases which were founded on different beds with a view to determining the effect of the bed on the strength of the base. The tests show that the bed has an appreciable effect on the strength and that a given base can withstand a much greater failing load on a sand bed than on a clay bed Part III describes a series of tests carried out on bases with different amounts of reinforcement, the bed being kept constant. The tests showed that the failure of a thin base is due to flexure and not to shear: in addition they showed that for any given diameter of bar the increase in strength is proportional to the area of reinforcement. The tests also showed the advantage of the use of reinforcement with good anchorage.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available