Cálculo simplificado de flechas instantáneas en vigas de hormigón sometidas a flexión compuesta. Método propuesto para la instrucción de hormigón pretensado EP-93

Simplified calculation of instantaneous deflections in concrete beams under compound bending. Proposed method for the Spanish Code of Prestressed Concrete EP-93

The Spanish and European Concrete Codes propose simplified methods for the calculation of instantaneous deflections in concrete members under simple bending. However, these Codes, don't have simplified methods for elements under compound bending. A general method by means of integration of curvatures for any solicitation (simple or compound bending) is presented in the Model Code 90. For practical applications, MC-90 refers to CEB. Bulletin 158 (Manual on Cracking and Deformations). In this Bulletin a bilineal simplified moment-cu rvature relationship for any section under compound bending is given. In this paper it is presented a simplified method for the calculation of instatntaneous deflections in concrete members under compound bending, including prestress. A systematicc contrast is made against the general method of integration of curvatures given in the Model Code 90, for several cases, where it can be proved the validity of the proposed method.