Modelo de análisis de secciones para evaluar la respuesta hasta rotura, por solicitaciones normales y/o tangentes, de estructuras de hormigón pretensado

A model of sectional analysis for evaluating the response up to failure by bending, shear and torsion of prestressed concrete structure

In this paper, a theoretical model for the anlysis of reinforced or prestressed concrete sections, taken into account the material non linearities and the interaction among bending, shear and torsion forces, is presented. The model is formulated for the study of thin walled closed sections, and the behaviour of solid sections can be evaluated through the use of an effective thick of wall. From a given sectiona strains and applying the commo assumpptions; (Navier's hypotesis and section indistrosionability), axial and tangent strains in every point of section are deducced. Using constitutive laws for uncracked and cracked concrete and steel, normal and shear stresses are obtained and, internal forces, bending, shear and torsion, are deduced by integration. The validation of theoretical model is carried out comparing the theoretical results with experimental tests published in national and international journals, existing, in general, a very good agreement. Finally, two concrete box sections are analyzed, and interesting conclusiions about bending, shear and torsion interaction in this kind of sections are presented.