Shear strengthening of continuous reinforced concrete t-beams using deep embedment technique

Despite numerous studies, shear behaviour before or after strengthening is still not fully understood, particularly in continuous concrete structures which are the norm. Upgrading shear resistance is altogether more difficult since Externally Bonded Reinforcement (EBR) or Near Surface Mounted (NSM) techniques do not allow the FRP material to be anchored into the compression zone of the T-beams and they cannot be used in cases where the sides of the beams are inaccessible. An innovative retrofit technique, named Deep Embedment (DE) or Embedded Through Section (ETS) technique involves the insertion of FRP/steel bars upwards into vertical or inclined holes which have been drilled from the soffit of concrete beams. In this way, the tension and compression chords of the beams are directly connected while the bars are bonded to the concrete core through adhesives. With this technique strengthening can be done in cases where the webs are inaccessible. Thus the main focus of this study is to significantly contribute to the current knowledge on the behaviour of Reinforced Concrete continuous T-beams
strengthened in shear using the DE technique where large shear forces are combined with large negative bending moments. An experimental program consisting of ten two-span continuous T-beams designed to fail in shear was
carried out in order to significantly contribute to the current knowledge on the behaviour of RC continuous Tbeams strengthened in shear using this technique. Therefore, this paper reports on the test results and on their significance in being able to apply this technique on concrete structures by validating them through adequate analytical models.