Embedded Through-Section shear strengthening technique using steel and CFRP bars in RC beams of different percentage of existing stirrups

Abstract

The Embedded Through-Section (ETS) technique is a promising technique for the shear strengthening of\ud existing (RC) elements. According to this technique, holes are drilled through the beam section, and bars\ud of steel or FRP material are introduced into these holes and bonded to the concrete with adhesive materials.\ud An experimental program was carried out with RC T-cross section beams strengthened in shear\ud using the ETS steel bars and ETS CFRP rods. The research is focused on the evaluation of the ETS efficiency\ud on beams with different percentage of existing internal transverse reinforcement (qsw = 0.0%, qsw = 0.1%\ud and qsw = 0.17%). The effectiveness of different ETS strengthening configurations was also investigated.\ud The good bond between the strengthening ETS bars and the surrounding concrete allowed the yield initiation\ud of the ETS steel bars and the attainment of high tensile strains in the ETS CFRP rods, leading to\ud significant increase of shear capacity, whose level was strongly influenced by the inclination of the ETS\ud bars and the percentage of internal transverse reinforcement

Experimentally Comparative Study on Different Strengthening Methods of Reinforced Concrete Deep Beams

“…Khattab et al (2017) studied reinforced concrete deep beams and concluded that increasing of strips lead to an increase in beam capacity [1]. Using of FRP sheets in the strengthening of deep beams, increase beam capacity [2][3][4][5][6][7], also using of FRP bars in the strengthening of deep beams led to increasing beam capacity [8][9][10]. Another researcher studies other parameters that shall be considered in the design of deep beams [11][12][13].…”

Simultaneous flexural and punching strengthening of RC slabs according to a new hybrid technique using U-shape CFRP laminates

“…Studies have shown that the NSM technique offers higher strengthening effectiveness than the EBR technique due to higher confinement to the CFRP composite materials provided by the surrounding concrete [2,[7][8][9]. The ETS technique has been used with considerable success for the shear strengthening of RC beams, where FRP or steel bars are installed into vertical or inclined holes drilled through the core of the beam's cross section [10].…”

RC beams strengthened in shear using the Embedded Through-Section technique: Experimental results and analytical formulation

“…This technique is based on the execution of holes drilled through the element cross section, in which steel or fiber reinforced polymer (FRP) bars are inserted and bonded to the surrounding concrete with an epoxy adhesive. Different FRP-2 based strengthening techniques, like Externally Bonded Reinforcement (EBR) and Near Surfaces Mounted (NSM), are being investigated and applied for the shear strengthening of RC beams; however the ETS technique was proved to be particularly efficient, providing a significant increase of shear resistance, usually higher than the one attained by using NSM and EBR techniques [1][2][3][4][5]. The ETS technique is also a cost competitive and feasible solution when EBR and NSM techniques cannot be applied [6].…”

“…Three series of beams with different percentage of existing steel stirrups were tested with the purpose of evaluating the influence of the internal shear reinforcing ratio, as well as the influence of the percentage and inclination of the ETS bars on the strengthening effectiveness. A detailed description of the experimental program and the discussion of the results are presented in Breveglieri et al [4,5].…”