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Shear Bearing Behaviour of Slender Reinforced Concrete Members Without Shear Reinforcement Containing a Low Ratio of Longitudinal Reinforcement
Abstract Eurocode 2 (EC 2) provides a verification procedure for members not requiring design shear reinforcement that was derived by means of statistical analysis of results from shear tests but, however, offers no mechanical background. Especially the minimum shear resistance acc. to EC 2 which is decisive for members with small ratios of longitudinal reinforcement doesn’t seem to be sufficiently validated for lack of an adequate number of test data. This unsatisfying situation can essentially be improved not only by simply extending the existing shear database but by establishing a mechanical based model. As a first step the structural behaviour and failure mechanisms of members without shear reinforcement with low ratio of longitudinal reinforcement were studied in 26 3-point-tests. The test specimens had a cross section of b/h/d [cm] = 32/23/20 and reinforcement ratios 0.223% ≤ ρl ≤ 3.34%. The higher reinforcement ratios were included in the test series in order to form a link with results from literature. The experimental work will be followed by theoretical investigations. The results of the shear tests presented in this paper do not support the existence of a minimum shear resistance and reveal the need of further research on this topic. The test observations underline that the failure mechanism is mainly affected by the arbitrary formation of (bending) cracks. For comparability and reliable classification of test results it is therefore necessary to distinguish between an original shear failure initiated by the growth of a bending crack on the one hand and failure after formation of an inner truss frame (or an arch-tie-model in the case of uniformly distributed load) on the other hand. Considering the mechanism of a truss frame as a kind of shear resistance in structural design may however not be conservative and would require adjusting the rules for detailing of reinforcement and members in EC 2.
Shear Bearing Behaviour of Slender Reinforced Concrete Members Without Shear Reinforcement Containing a Low Ratio of Longitudinal Reinforcement
Abstract Eurocode 2 (EC 2) provides a verification procedure for members not requiring design shear reinforcement that was derived by means of statistical analysis of results from shear tests but, however, offers no mechanical background. Especially the minimum shear resistance acc. to EC 2 which is decisive for members with small ratios of longitudinal reinforcement doesn’t seem to be sufficiently validated for lack of an adequate number of test data. This unsatisfying situation can essentially be improved not only by simply extending the existing shear database but by establishing a mechanical based model. As a first step the structural behaviour and failure mechanisms of members without shear reinforcement with low ratio of longitudinal reinforcement were studied in 26 3-point-tests. The test specimens had a cross section of b/h/d [cm] = 32/23/20 and reinforcement ratios 0.223% ≤ ρl ≤ 3.34%. The higher reinforcement ratios were included in the test series in order to form a link with results from literature. The experimental work will be followed by theoretical investigations. The results of the shear tests presented in this paper do not support the existence of a minimum shear resistance and reveal the need of further research on this topic. The test observations underline that the failure mechanism is mainly affected by the arbitrary formation of (bending) cracks. For comparability and reliable classification of test results it is therefore necessary to distinguish between an original shear failure initiated by the growth of a bending crack on the one hand and failure after formation of an inner truss frame (or an arch-tie-model in the case of uniformly distributed load) on the other hand. Considering the mechanism of a truss frame as a kind of shear resistance in structural design may however not be conservative and would require adjusting the rules for detailing of reinforcement and members in EC 2.
Shear Bearing Behaviour of Slender Reinforced Concrete Members Without Shear Reinforcement Containing a Low Ratio of Longitudinal Reinforcement
Riedel, Philipp (Autor:in) / Leutbecher, Torsten (Autor:in)
06.08.2017
9 pages
Aufsatz/Kapitel (Buch)
Elektronische Ressource
Englisch
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