FRP-RC/PC members subjected to combined actions

The capacity provisions of conventional Reinforced Concrete (RC) and Prestressed Concrete (PC) beams subjected to combined action of torsion, shear and flexure are well known and stated by international/national codes. Similar provisions lack for concrete members containing Fibre Reinforced Polymer (FRP) reinforcements. In general, there is paucity of research on the treatment of torsion combined with other stress resultants for FRP-RC/PC members. In this paper the theoretical method proposed by the Canadian standard CSA S806 for FRP-RC/PC structures is presented. The critical issues, related to this topic, such as the appropriate strength and inclination of the diagonal struts and failure criteria are critically analyzed and addressed. In order to assess the reliability of this study a comparison between available experimental data regarding FRP-RC/PC beams subjected to combined actions and their corresponding theoretical provisions derived by the CSA S806 standard is shown. Furthermore, another approach, available in literature, which is based on the space truss model, is examined and used for comparison in order to evaluate the theoretical provisions offered by this model against the tests value of the set of the beams analyzed in this study. Based on the critical analysis of the results, it can be highlighted that the CSA method is able to conservatively predict the capacity of these beams.