Resumen de Control de la fisuración a cortante y flexión mediante pretensado parcial
Jesús Miguel Bairán García, Denise Carina Santos Ferreira, Noemí Duarte Gómez, Antonio R. Marí Bernat, Ulric Celada Blesa
Partially prestressed concrete, considered as the prestressed not designed to avoid concrete cracking, but as an effective means for crack control and other service performance, is gaining newly interest in practical design; in part, motivated by the development of new performance based design codes. Among the main advantages of partially prestressed concrete, it should be mentioned the more freedom of the designer to optimize structures in terms of specific needs of each project, reduction of material and weight. On the other hand, it also provides more ductility, in comparison to fully prestressed concrete elements, allows redistribution of internal forces, etc.
However, the behaviour of cracked partially prestressed concrete is complex, being non linear even in service loading; for this reason, adequate methodologies and models are needed for its full application in engineering practice. The actual state of the knowledge on the behaviour of concrete structures, both in service and ultimate loading, is particularly high in what respects non tangential loading, and has produced well-established theories and models that are suitable to be applied to prestressed-concrete; however, there are still numerous aspects in which are not directly extrapolated, further research needs to be deepen as no consolidated theory or model are still available for its application in practicing engineering. Among these topics one may mention cracking verification under bending and shear loading, the use of partially prestressed concrete to control them. In this sense, the influence of different variables are to be defined, such as the prestresseing degree, spacing of amount of transversal reinforcement, longitudinal reinforcement, crack inclination, etc.
In this paper, a review of the state of art regarding cracking in prestressed concrete elements under bending and shear is presented. The current design tendencies of different contexts are analysed and discussed, and the topics where higher discrepancies exists both in research and codes are identified. Furthermore, a numerical study by means of advanced non linear methods is carried out and used to design an experimental campaign.
