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Abstract

A review of research on the shear strength of reinforced concrete beams is given, indicating that although reliable empirical conclusions can be made about beam behaviour, little is known about the way in which reinforced concrete beams carry shear.

Extensive tests are described in which the distribution of shear force in a beam subjected to combined bending and shear is studied. In the first of the tests, the shear force carried by beam compression zones was investigated and these tests showed that only a quarter of the total shear force is carried by the compression zone. The shear force carried across the cracks in beams was then studied, in two investigations. Firstly the force carried across cracks by the main tension steel acting as a dowel was measured in a series of model and prototype tests. Secondly the forces carried across cracks by interlock of the aggregate were estimated in two separate tests, one on cracked blocks of concrete and one on beams specially designed to eliminate other methods of shear transfer.

The strains and displacements from elastic analysis of the concrete cantilevers between cracks loaded by the measured force in the beams are shown to be consistent with the observed crack patterns in beams.

A mathematical model is then described in which the path of a shear crack and distribution of shear forces was found in beams by considering the equilibrium and compatibility of displacements of the parts of the beams separated by a section through the crack and beam compression zone.

Finally the implication of these theories in explaining the behaviour of beams with stirrups was considered and some experimental evidence is given of the internal distributions of shear forces in beams with stirrups.

Publication Type:	Thesis (Doctoral)
Additional Information:	EThOS request
Subjects:	T Technology > TA Engineering (General). Civil engineering (General)
Departments:	Doctoral Theses School of Science & Technology > School of Science & Technology Doctoral Theses School of Science & Technology School of Science & Technology > Engineering

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