Author: Zhizhou Bai

Publisher:

Published: 2017-01-27

Total Pages:

ISBN-13: 9781361429433

This dissertation, "Nonlinear Analysis of Reinforced Concrete Beams and Columns With Special Reference to Full-range and Cyclic" by Zhizhou, Bai, 白植舟, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of thesis entitled NONLINEAR ANALYSIS OF REINFORCED CONCRETE BEAMS AND COLUMNS WITH SPECIAL REFERENCE TO FULL-RANGE AND CYCLIC BEHAVIOUR Submitted by BAI Zhizhou for the degree of Doctor of Philosophy at The University of Hong Kong in December 2006 In this thesis, the full-range flexural behaviour of reinforced concrete (RC) beams and columns made of normal- and high-strength concrete under both monotonic and cyclic loading is studied. The full-range moment-curvature relationships are obtained based on a numerical method that considers the cyclic response of constitutive materials. A two-dimensional nonlinear finite element procedure is also developed for the analysis of RC beams under monotonic and non-reversed cyclic loading. For RC beam sections, it is found that the full-range flexural behaviour is basically dependent on the tension steel to balanced steel ratio. The full-range moment-curvature curves for under-reinforced sections have long yield plateaus while those for over-reinforced sections have sharp peaks. The full-range moment-curvature curves under monotonic loading in sagging and hogging moments are found to give the envelope for cyclic response. Reversed cyclic loading generally creates overall residual tensile strains in RC sections, and is especially significant for under-reinforced sections. The variation of neutral axis depth during monotonic and cyclic loading shows different trends for under- and over-reinforced sections. For RC column sections, it is found that the full-range flexural behaviour is strongly dependent on the axial load and confinement, which govern the moment capacity, ductility and failure mode of an RC column. The flexural ductility is generally reduced by compressive axial load but increased by confinement. The moment-curvature curve of a section under tensile axial load or relatively low compressive axial load has a long plateau around peak moment, while that under relatively high compressive axial load has a sharper peak. The complete moment-curvature curves under monotonic loading in sagging and hogging moments give the envelope for cyclic response except for sections under very high compressive axial load. A section under tensile axial load or low compressive axial load tends to elongate after a complete cyclic loading, while a section under high compressive axial load tends to shorten. The variations of neutral axis depth and steel stresses are also dependent on the axial load and confinement. The effect of concrete tensile strength is only notable for under-reinforced RC beam sections and for RC column sections under tensile axial load or relatively low compressive axial load at the service stage. The Bauschinger effect of steel is negligible in the case of RC sections undergoing non-reversed cyclic loading, but becomes significant for reversed cyclic loading that is extended into large inelastic deformation. Besides section analyses, a two-dimensional nonlinear finite element procedure is also developed for better understanding of the behaviour of RC beams under monotonic and non-reversed cyclic loading. In particular, the local bond-slip effect is modelled by linear displacement contact elements. The numerical predictions are validated by experimental results. With the proper choice of bond parameters, results show that the procedure is capable of modelling the for