Experimental Evaluation of the Efficiency of FRCM-U-Wrap Joist Tech for Flexural Improvement of RC Beam

The paper reports the results of an experimental investigation aimed to the assessment of the enhancement of the flexural capacity of RC beam. The technology employed is based on the use of Fiber- Reinforced Cementitious Matrix (FRCM). The patented system, called FRCM U-Wrap-Joist Tech provides a new methodology for beam strengthening capable of generating a higher internal couple of the cross section with no incisive change of the element weight. That can be aimed by the employment of a poor weight joist, joined at the intrados of the original beam and connected to the extremities with two reoplastic mortar blocks. The joist was, then, jacked in a FRCM material based on PBO composite net. This produces an increment of the compressed zone of the cross section and it lowers traction stress values in steel as well as compression stress values in concrete. Experimental evidence gives back an increase in flexural strength equal to the double than the original non-reinforced beam, as well as a, considerably, greater than the reinforced beam according to traditional technology where the fiber net is directed glued to the beam intrados. So, this methodology seems to be very useful in the case of a transformation of the use destination of a civil structure when an increase of the resistant section is required and in any case of seismic strengthening intervention.