Resumo

GODOY B, Dilio A  e  LOPEZ, Oscar A. Evaluation of spectral methods for the design of reinforced concrete columns for plane structures. Rev. Fac. Ing. UCV [online]. 2007, vol.22, n.1, pp.21-36. ISSN 0798-4065.

The main objective of this investigation is to evaluate the traditional method of spectral design of columns that considers the probable maximum values of the axial force and the bending moment, for plane structures of reinforced concrete under a single seismic component. With this purpose, this method is compared with more refined methods recently proposed, the Extreme Stress and the Extreme Force Methods, which use the concept of probable simultaneous values of axial force and bending moment. The design values using those methods are also compared with the set of possible values of axial force and bending moment whose envelope is given by the interaction ellipse of Gupta. Simplified models of 1, 2 and 8-story plane structures for buildings with rigid beams and buildings with flexible beams were defined, with a short and a long period, under a horizontal seismic component along one of the main axes of the structure. The relative error between the probable maximum forces and the probable simultaneous forces was determined, taking the last ones as more reliable values for design purposes. The errors found are always in excess. In conclusion, the traditional method is conservative, the proposed methods are more accurate and the reinforcement bar areas in the design of reinforced concrete columns calculated with the probable maximum forces, can be exceeded up to 260% in buildings of medium height, in relation to a more reliable design based on the probable simultaneous values. spectral methods, reinforced concrete columns, plane structures, probable maximum values, probable simultaneous values.

Palavras-chave : métodos espectrales; columnas de concreto armado; estructuras planas; valores máximos probables; alores simultáneos probables.