TÓM TẮT NGHIÊN CỨU THỰC NGHIỆM Hussein
FLEXURAL BEHAVIOR OF REINFORCED CONCRETE BEAM STRENGTHENED WITH TEXTILE REINFORCED CONCRETE Strengthening of reinforced concrete structures using textile reinforced concrete (TRC) has emerged as a viable technique to retrofit/repair deteriorated structures. In this study, the flexural performance of concrete beams strengthened with TRC has been investigated by means of a finite element analysis on ABAQUS software. The work reported in this paper deals with the analytical models, proposed to predict the behavior of reinforced concrete beam strengthened with externally bonded TRC layers. The surface – based cohesive behavior is also captured to represent the interfacial bonding between TRC and concrete substrate. The results of the numerical simulations are used to validate the experimental results. .
Flexural strengthening of RC beams using textile reinforced mortar – Experimental and numerical study
Abstract In this paper, the effectiveness of textile reinforced mortars (TRMs), as a means of increasing the flexural capacity of reinforced concrete (RC) beams, is experimentally and numerically investigated. A new type of textile (basalt-based textile) was used as strengthening material. The studied parameters included type of mortar, number of TRM layers and type of strengthening material: TRM versus carbon fiber-reinforced polymer (CFRP) composites. A total of six beams were tested under four-point bending till failure. Two beams were used as control specimens. Three beams were externally upgraded by TRM sheets for enhancing their flexural capacity; and one beam was strengthened with CFRP laminates for comparison with its TRM counterpart. Besides the experimental program, a numerical investigation utilizing nonlinear finite element (FE) analysis was carried out using LS-DYNA software. In addition to the six beams tested in this study, another three beams were collected from the literature for the purpose of finite element validation. A comparison was made between the experimental and numerical results and good agreement was obtained. Based on the validation of FE results, the numerical analysis was extended to include additional cases to study the flexural enhancement of RC beams using more TRM layers with different end anchorages.
Strengthening of two-way reinforced concrete slabs with Textile Reinforced Mortars (TRM)
An innovative strengthening technique is applied for the first time in this study to provide flexural strengthening in two-way reinforced concrete (RC) slabs supported on edge beams. The technique comprises external bonding of textiles on the tension face of RC slabs through the use of polymer-modified cement-based mortars. The textiles used in the experimental campaign comprised fabric meshes made of long stitch-bonded fibre rovings in two orthogonal directions. The specimens measured 2 x 2 m in plan and were supported on hinges at the corners. Three RC slabs strengthened by textile reinforced mortar (TRM) overlays and one control specimen were tested to failure. One specimen received one layer of carbon fibre textile, another one received two, whereas the third specimen was strengthened with three layers of glass fibre textile having the same axial rigidity (in both directions) with the single-layered carbon fibre textile. All specimens failed due to flexural punching. The load-carrying capacity of the strengthened slabs was increased by 26%, 53%, and 20% over that of the control specimen for slabs with one (carbon), two (carbon) and three (glass) textile layers, respectively. The strengthened slabs showed an increase in stiffness and energy absorption. The experimental results are compared with theoretical predictions based on existing models specifically developed for two-way slabs and the performance of the latter is evaluated. Based on the findings of this work the authors conclude that TRM overlays comprise a very promising solution for the strengthening of two-way RC slabs.