Design Aids for Beams of Rectangular Cross Section with Parabolic Haunches: Part 1

Carla Yaneth Crispín Herrera, Arnulfo Luévanos Rojas, Sandra López Chavarría, Manuel Medina Elizondo


In this paper, the most used design aids for beams of rectangular section with parabolic haunches are presented. The variables considered are: the heights at its two ends vary parabolically, the width of the beam is constant, and the height in the central part is constant. The beam is found subjected to a uniformly distributed load, which takes into account the bending and shear deformations to obtain the fixed-end moments factors, the carry-over factors and the stiffness factors, which is the main contribution of this research work. The simplifications are: the heights at its two ends are equal, as these are the most used by aesthetics in architectural constructions, and the total height of the beam in the central part is considered of 0.10 of the length of the beam according to the ACI (American Concrete Institute) code for deflection control. Also, a numerical example is shown using the design aids, and it is compared with the equations previously described by the authors in an article prior to this document, and the results are equal to a three-digit approximation. Therefore, design aids provide a great tool of help for structural engineers by the greatly time-savings.


Design aids, rectangular berms, parabolic haunches, uniformly distributed load, fixed-end moments factors, carry-over factors, stiffness factors

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