Rigidez a flexión EI para el método de amplificación de momentos en soportes esbeltos de sección rectangular de hormigón armado sometidos a esfuerzos de flexo-compresión recta

Flexural rigidity EI of RC slender columns under axial force and bending of rectangular section for the moment magnifier meted

In this paper, a new expression is proposed for the flexure rigidity EI of RC slender columns under instantaneous and sustained axial force and bending, with rectangular cross-section, symmetrically reinforced in both axes, valid not only for normal strength concrete but for high strength concrete. The proposed expression has been derived from the results of a numeric simulation and has been checked against 238 experimental tests. This proposed expression has been compared with the ACI- 318 and EC-2 proposals. It has been observed a remarkable improvement in the accuracy with the proposed expression with regard to the proposed by both cases. The proposal allows verification and design of slender columns with enough accuracy for the professional practice. This method is applicable to an important percentage of columns in buildings.