Experimental and numerical assessment of the effectiveness of FRP-based strengthening configurations for dapped-end RC beams

Abstract

The load carrying capacity (hereafter capacity, for convenience) of dapped-end beams may be insufficient for reasons such as design errors, code changes, increases in loads, or structural damage. One option to increase the capacity of the dapped-end regions is to use fiber-reinforced polymers (FRP) using the externally bonded reinforcement (EBR) technique. FRPs are viable solutions for strengthening or retrofitting reinforced concrete (RC) elements, and several guidelines for strengthening RC structures with FRPs have been published recently [10-12]. However, these guidelines do not refer specifically to FRP strengthening of dapped-end beams, partly because the variations in geometry, material and loading conditions at their dapped ends hinder the establishment of clear criteria for robustly classified strengthening configurations.In a series of tests, Huang and Nanni [13] verified that FRPs can increase the capacity of dapped-end beams with "mild steel and no mild reinforcement" [13], and proposed a method for strengthening dapped-end beams with FRPs that was found to be "satisfactory and conservative" [13]. They too showed that dapped-end reinforcement

Proposal and experimental validation of simplified strut-and-tie models on dapped-end beams

“…Despite standard concrete details and extensive past experimental research [1][2][3][4][5][6][7][8][9][10], major durability issues, and even collapses, have been observed in DEB structures [11,12]. This explains the numerous studies performed lately on DEB [13][14][15][16][17][18][19][20][21][22][23][24], which focus mainly on strengthening measures, durability and the impact of deficient detailing. A detailed overview of the dimensions and characteristics of experimental tests on reinforced concrete DEB reported in the literature can be found elsewhere [12,22].…”

Shear Failure of RC Dapped-End Beams

“…It has been reported that all the strengthening methods are enhancing the shear strength capacity of RC-DEBs; however, the unbounded inclined steel bolts method has yielded better results. In addition, experimental results reported by Huang and Nanni [6] and Nagy-György et al [10] showed that the shear strength capacity of the RC-DEBs can be significantly increased by using CFRP strengthening. Other approaches by focusing on different types of concrete to enhance the shear strength capacity of RC-DEBs have been investigated by Mohamed and Elliot [11].…”

Experimental investigation and strength model of RC deep beams externally bonded by CFRP

“…Strengthened beams bonded with bolts showed better shear resistance as compared to its counterpart. Nagy-György et al (2012) performed experimental study on beams strengthened with CFRP sheet applied in different orientations. It was noted that CFRP applied perpendicular to the crack pattern showed a large contribution in strength.…”