Prestressed FRP Fabrics for Flexural Strengthening of Concrete

The feasibility and advantages of strengthening reinforced concrete (RC) beams by prestressed Fibre-Reinforced-Polymer (FRP) fabrics are examined.Actually this is possible, as a prestressing machine has been designed, suitable to properly seize and prestress the fabric, without risk of ripping it. The device is illustrated and the case of RC beams with inadequate steel reinforcement for bending is treated. A method is proposed and the analytical verifications are shown, that make use of closed-form equations and follow the usual steps commonly taken when strengthening, i.e. to assess the resisting moment capacity of the existing beam, toevaluate the demanded strength increase and to design the amount and prestress level of the strengthening. A design example is also given