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Structural Engineering and Mechanics   Volume 67, Number 5, September10 2018, pages 465-479
DOI: https://doi.org/10.12989/sem.2018.67.5.465
 
Effective torsional strength of axially restricted RC beams
Catia S.B. Taborda, Luis F.A. Bernardo and Jorge M.R. Gama

 
Abstract     [Buy Article]
    In a previous study, design charts where proposed to help the torsional design of axially restricted reinforced concrete (RC) beams with squared cross section. In this article, new design charts are proposed to cover RC beams with rectangular cross section. The influence of the height to width ratio of the cross section on the behavior of RC beams under torsion is firstly shown by using theoretical and experimental results. Next, the effective torsional strength of a reference RC beam is computed for several values and combinations of the study variables, namely: height to width ratio of the cross section, concrete compressive strength, torsional reinforcement ratio and level of the axial restraint. To compute the torsional strength, the modified Variable Angle Truss Model for axially restricted RC beams is used. Then, an extensive parametric analysis based on multivariable and nonlinear correlation analysis is performed to obtain nonlinear regression equations which allow to build the new design charts. These charts allow to correct the torsional strength in order to consider the favourable influence of the compressive axial stress that arises from the axial restraint.
 
Key Words
    reinforced concrete; beams; torsion; axial restraint; torsional design; charts
 
Address
Catia S.B. Taborda and Luis F.A. Bernardo: Department of Civil Engineering and Architecture, Centre of Materials and Building Technologies (C-Made), University of Beira Interior, Covilha, Portugal
Jorge M.R. Gama: Department of Mathematics, Center of Mathematics and Applications, University of Beira Interior, Covilha, Portugal
 

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