New technique for strengthening square-reinforced concrete columns by the circularisation with reactive powder concrete and wrapping with fibre-reinforced polymer

Abstract

This paper presents a new strengthening technique for square-reinforced concrete (RC) columns by circularisation with reactive powder concrete (RPC) and wrapping with fibre-reinforced polymer (FRP). RC column specimens were tested, divided into four groups of four specimens based on the strengthening technique: four reference square specimens (150mm side length) without any strengthening, four were wrapped with two layers of carbon fibre-reinforced polymer (CFRP) and the remaining eight were strengthened by changing the square cross-section to a 240mm diameter circle with RPC jacket. Four of the RPC jacketed specimens were left unwrapped, while the last four were wrapped with two layers of CFRP. From each group, one specimen was tested under concentric axial load, two were tested under eccentric axial load and one was tested under four-point bending. It was found that using the RPC for circularisation and strengthening of existing square RC columns is an effective technique to significantly increase their axial carrying capacity, ultimate flexural load and energy absorption. Wrapping the circularised RC columns with CFRP prevented the failure of the RPC jacket at the corners of the existing square RC columns under the axial load, and improved the ultimate load as well as the energy absorption of the circularised RC columns.

Computer simulation of reinforced concrete columns confined with CFRP

“…This work was carried out using the experimental results of research by Wang et al [6], Atheer et al [7], and Souza [8] as a reference in terms of comparison to validate the computational model used. The computational modeling was performed using the Ansys Workbench 17.1 software, which performs simulations using the finite element method.…”

“…For the columns of Wang et al [6], meshes of 7,625 mm were used in x and y directions for concrete, while for CFRP, a mesh of 20 mm was employed. In the columns of Atheer et al [7], meshes of 7.5 mm were adopted in x and y directions for concrete, and a mesh of 12.5 mm was defined for CFRP. Finally, in the columns of Souza [8], were used meshes of 6.25 mm in the x-direction and 28.52 mm in the y-direction for concrete and a mesh of 12.5 mm was defined for CFRP.…”

Axial compression capacity analysis of prefabricated steel reactive powder concrete columns in prefabricated modular buildings

“…Yan et al (2010) investigated the bond behavior at the interface between the RPC and the steel tube and developed a nonlinear finite element model for the contact interface. Algburi et al (2019) studied the mechanical properties of square reinforced concrete columns strengthened by wrapping with RPC and fiber-reinforced polymer (FRP). Their results showed that both RPC and FRP strengthening significantly improved the ultimate bearing capacity and energy absorption of the specimens and that wrapping with carbon FRP sheets prevented the shear failure at the corners of the columns.…”

Enhancing flexural capacity of RC columns through near surface mounted SMA and CFRP bars

“…Therefore, there is still a need to develop efficient strengthening methods for RC columns such that they meet the flexural requirements of modern codes and standards. 5–8…”

“…Therefore, there is still a need to develop efficient strengthening methods for RC columns such that they meet the flexural requirements of modern codes and standards. [5][6][7][8] Over the past two decades, near surface mounted (NSM) strengthening technique has gained considerable interest as an alternative method to externally bonded strengthening of RC structures. In the NSM technique, FRP bars or strips are inserted into precut grooves on the concrete cover of RC structural element to be strengthened, then the grooves are filled with an epoxy paste or cement-based mortar.…”