Combined Flexural and Shear Strengthening of RC T-Beams with FRP and TRM: Experimental Study and Parametric Finite Element Analyses

Abstract

Due to inadequacies of reinforcement design in older structures and changes in building codes, but also the change of building use in existing structures, reinforced concrete (RC) beams often require upgrading during building renovation. The combined shear and flexural strengthening with composite materials, fibre-reinforced polymer sheets (FRP) and textile reinforced mortars (TRM), is assessed in this study. An experimental campaign on twelve half-scale retrofitted RC beams is presented, looking at various parameters of interest, including the effect of the steel reinforcement ratio on the retrofit effectiveness, the amount of composite material used for strengthening and the effect of the shear span, as well as the difference in effectiveness of FRP and TRM in strengthening RC beams. Significant effects on the shear capacity of composite retrofitted beams are observed for all studied parameters. The experimental study is used as a basis for developing a detailed finite element (FE) model for RC beams strengthened with FRP. The results of the FE model are compared to the experimental results and used to design a parametric study to further study the effect of the investigated parameters on the retrofit effectiveness.

Perspectives and Specific Features of the Use of Composite Materials for Strengthening of Damaged Reinforced Concrete Structures

“…Thus, gluing the tape to the lower face of the RC beam contributes to absorbing blast energy, while the use of diagonal tapes on the side face of beams and U-shaped systems allows to increase shear strength (Jahami et al, 2021). Detailed experimental study, dedicated to assessment of combined shear and bending reinforcement systems using fiber-reinforced polymer (FRP) and textile reinforced mortar (TRM) composite materials confirmed the increase in shear load-bearing capacity and other parameters of behavior under loading (Pohoryles et al, 2021). This was also confirmed by study of Abdalla et al, who indicated a significant increase in the load-bearing capacity for bending and shear when using composite tapes for wrapping RC beams in combination with rod anchors (Abdalla et al, 2022).…”

Cracking and failure mode behavior of hybrid FRP strengthened RC column members under flexural loading

“…The existing civil infrastructure, like buildings, bridges and marine structures, often require repair and strengthening for various reasons. The various reasons for the repair and strengthening are (i) aging of infrastructure, (ii) corrosion and deterioration due to extreme environmental conditions, 1,2 (iii) damage due to accidental loading such as impact and blast, 3,4 (iv) upgradations due to change in use and additional loading requirements, 5–7 (vi) seismic strengthening and retrofitting 8–10 and (vii) address the defects in design and execution. The fiber‐reinforced polymer (FRP) composites have been widely adopted for the strengthening of reinforced concrete (RC) elements over the last few decades 11–14 .…”

Implementation of Modified Compression Field Theory to Simulate the Behavior of Fiber-Reinforced Polymer Shear-Strengthened Reinforced Concrete Beams under Monotonic Loading

“…An extensive number of existing reinforced concrete structures are persistently exposed to damage induced by the deterioration of concrete, natural environmental effects, and corrosion of steel. This might be attributed to the continuous increase in the load requirements compared to what they were originally designed for, the change in the structure's function, and the necessity to meet the current design standards [1]. Repair and strengthening would be an efficient or economical option instead of removing all these structures and replacing them with new ones [2,3].…”

“…1 Span length; 2 web width; 3 flange width; 4 web height; 5 flange height; 6 shear span-to-depth ratio.…”