scholarly journals Comparative Approach to Flexural Behavior of Reinforced Beams with GFRP, CFRP, and Steel Bars

2020 ◽  
Vol 6 (1) ◽  
pp. 50-59 ◽  
Author(s):  
Naser Kabashi ◽  
Besart Avdyli ◽  
Enes Krasniqi ◽  
Arbër Këpuska
Keyword(s):  
Concrete Beams ◽  
Limit State ◽  
Experimental Results ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Comparative Approach ◽  
Geometrical Parameters ◽  
Reinforced Beams ◽  
Steel Bars ◽  
Different Diameters

The replacement of conventional steel bars with GFRP or CFRP is one of the main topics discussed in this paper, including the main parameters and properties of the materials. The design procedures should account for the properties and will focus on the tensile strength and modulus of elasticity. It will also consider corrosion under environmentally aggressive conditions. This paper presents an experiment on the flexural behavior of concrete beams reinforced with GFRP and CFRP bars and compares these results with theoretical analysis based on different standards such as ACI, Eurocode, and CSA. Twelve reinforced concrete beams will be tested using four-point loading. The geometrical parameters of the tested beams are 130×220×2200 mm, reinforced with different diameters for GFRP and CFRP.  The reinforcement ratio and strength of concrete influence the behavior of GFRP, CFRP, and RC beams and contribute to reduce the deflection and crack width. Based on this research, the closest approximation of the experimental results is observed with ACI standards. At this stage, these bars can be used in structures without strict requirements for exceeding the Serviceability Limit State. The non-integration of tension stiffening and regression performance of cracking moment in prediction expressions imposed the differences from experimental results.

scholarly journals Design of reinforced concrete beams with steel fibers in the ultimate limit state

2018 ◽  
Vol 11 (5) ◽  
pp. 997-1024
Author(s):  
T. E. T. BUTTIGNOL ◽  
J. F. FERNANDES ◽  
T. N. BITTENCOURT ◽  
J. L. A. O. SOUSA
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Limit State ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Experimental Results ◽  
Reinforced Concrete Beams ◽  
Ultimate Limit State ◽  
Bending Tests

Abstract This paper carries out a design analysis of reinforced concrete beams with steel fibers following the fib Model Code 2010 (MC 2010) procedures. The values obtained from the design calculations are compared with the experimental results of reinforced concrete beams with 20kg/m3 and 60 kg/m3 of steel fibers submitted to four-point bending tests. In the first part, the procedures for the classification and characterization of the material are explained. The experimental results of three-point bending tests performed on notched steel fiber reinforced concrete (FRC) beams following EN 14651 procedures are described. Moreover, the characterization of the FRC beams according to MC 2010, are carried out. In the second part, the flexural design of reinforced concrete beams with steel fibers, according to MC 2010, is carried out. A sectional analysis is performed in order to obtain the moment-curvature and the force-vertical displacement curves. The theoretical values are compared with the experimental results. Besides, a linear statistic analysis by means of the Rule of Mixture is carried out in order to analyze the variation of the flexural capacity of the reinforced beams with different amounts of steel fibers. The results demonstrated that the design rules described in the MC 2010 are on the safe side. The flexural resistance of concretes with different amounts of fiber incorporation can be determined by the Rule of Mixture, which has shown a high correlation factor (R2) with the experimental values.

Experimental Research on Bending Performance of Concrete Beams Reinforced with CFRP-PCPs Composite Rebars

2013 ◽  
Vol 438-439 ◽  
pp. 804-806
Author(s):  
Jiong Feng Liang ◽  
Jian Bao Wang ◽  
Jian Ping Li
Keyword(s):  
Experimental Research ◽  
Prestressed Concrete ◽  
Crack Width ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Experimental Results ◽  
Flexural Behavior ◽  
Bending Performance ◽  
Reinforced Beams

The flexural behavior of concrete beams reinforced with CFRP-PCPs composite rebars was studied. Experimental results showed that the deflection of beams reinforced with highly prestressed prisms is at service loads coMParable to deflection of steel reinforced beam. Flexural cracks of CFRP-PCPs composite rebars reinforced beams are hairline before prism cracking, and widened after the prism cracking. When the concrete beam was reinforced with the prestressed concrete prisms, the crack width decreased as the prestress in the prism increased.

scholarly journals Ductility Estimation of Concrete Beams Longitudinally Reinforced with Hybrid FRP-Steel Bars

2022 ◽  
Author(s):  
Rendy Thamrin ◽  
Zaidir Zaidir ◽  
Devitasari Iwanda
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Element Model ◽  
Neutral Axis ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Bending Test ◽  
Longitudinal Reinforcement ◽  
Steel Bars ◽  
Hybrid Reinforcement

An experimental study was carried out to evaluate the ductility of reinforced concrete beams longitudinally reinforced with hybrid FRP-Steel bars. The specimens were fourteen reinforced concrete beams with and without hybrid reinforcement. The test variables were bars position, the ratio of longitudinal reinforcement, and the type of FRP bars. The beams were loaded up to failure using a four-point bending test. The performance of the tested beams was observed using the load-deflection curve obtained from the test. Numerical analysis using the fiber element model was used to examine the growth of neutral axis depth due to the effect of test variables. The neutral axis curves were then used to further estimate the neutral axis angle and neutral axis displacement index. The test results show that the position of the reinforcement greatly influences the flexural behavior of the beam with hybrid reinforcement. It was observed from the test that the flexural capacity of beams with hybrid reinforcement is 4% to 50% higher than that of the beams with conventional steel bars depending on bars position and the ratio of longitudinal reinforcement. The ductility decreases as the hybrid reinforcement ratio (Af/As) increases. This study also showed that a numerical model developed can predict the flexural behavior of beams with hybrid reinforcement with reasonable accuracy.

Experimental Study on Flexural Behavior of Reinforced Concrete Beams with Variety Lap Splices of Reinforcing Steel Bars

2016 ◽  
Vol 845 ◽  
pp. 132-139
Author(s):  
Mochamad Teguh ◽  
Novia Mahlisani
Keyword(s):  
Experimental Study ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Reinforced Concrete Structures ◽  
Reinforcing Steel ◽  
Reinforcing Bars ◽  
Lap Splices ◽  
Steel Bars

The limited lengths of reinforcing bars have been commonly found in the practical construction of most reinforced concrete structures. The required length of a bar may be longer than the available stock of steel length. For maintaining desired continuity of the reinforcement in almost all reinforced concrete structures, some reinforcing bars should be carefully spliced. In the case of long flexural beam, bar installers end up with two or even more pieces of steel that must be spliced together to accomplish the desired steel length. An experimental study was conducted to investigate flexural behavior of reinforced concrete beams utilizing a variety lap splices of reinforcing steel bars under two-point loading. Five variations of lap splices of reinforcing steel bars positioned at midspan of tensile reinforcement of the beam were investigated. Welded joints and overlapped splices were used to construct the variation of lap splices of reinforcing steel bars. The general trend in crack pattern, the load deflection characteristics and the mode of failure of flexural beams under two-point loading were also observed. The flexural strength comprising load-displacement response, flexural crack propagation, displacement ductility is briefly discussed in this paper.

Experimental Investigation on Flexural Behavior of 500MPa Reinforced Concrete Beams with and without Skin Reinforcement

2013 ◽  
Vol 368-370 ◽  
pp. 1668-1673
Author(s):  
Zhi Hua Li ◽  
Xiao Zu Su
Keyword(s):  
Crack Width ◽  
Concrete Beams ◽  
Limit State ◽  
Crack Spacing ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Test Results ◽  
Average Crack ◽  
Maximum Crack ◽  
Short Time

Fourteen concrete beams reinforced with 500MPa longitudinal steel bars, of which 6 with skin reinforcement and 8 without skin reinforcement, were tested under two-point symmetrical concentrated static loading to investigate their flexural behavior. The results indicate that the flexural behavior and deflection mode of test beams with skin reinforcement are basically consistent with those of test beams without skin reinforcement. The use of skin reinforcement can significantly reduce average crack spacing and short-time maximum crack width. And the use of skin reinforcement can also slightly increase the short-time stiffness. Under the serviceability limit state, mid-span deflections are in good agreement with the calculated values according to formula in GB50010-2010. However most of calculated average crack spacing and short-time maximum crack width are larger than measured values. According to the test results, the normal formula of crack width should be revised.

scholarly journals STRESS-STRAIN STATE OF REINFORCED CONCRETE BEAMS STRENGTHENED WITH A NEW EXTERNAL STEEL STRUCTURE

2017 ◽  
Vol 1 (48) ◽  
pp. 90-99
Author(s):  
V. P. Zhyrakhivskyi ◽  
М. G. Chekanovych ◽  
О. М. Chekanovych
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
Concrete Beams ◽  
Rectangular Cross Section ◽  
Bending Moment ◽  
Steel Structure ◽  
Research Data ◽  
Reinforced Concrete Beams ◽  
Reinforced Beams ◽  
Steel Bars

The study presents a new structure for strengthening of one-span reinforced concrete beams in rectangular cross-section using external steel bars. The specific feature of the proposed strengthening is the unloading of the compressed upper zone of a beam with simultaneous compression of its lower stretched zone. The article considers some variants of making the strengthening structure with rigid and flexible reinforcement elements for faster tension of external bars, and the variant including only flexible elements. It provides a design scheme and method for such reinforced beams. The study provides experimental research data on the series of beams with different parameters of the strengthening structure in the form of «bending moment – deflection» and «bending moment - deformation of concrete» dependencies.

scholarly journals The computational analysis of the crack width of beams reinforced with CFRP and steel bars

2018 ◽  
Vol 183 ◽  
pp. 02003
Author(s):  
Kinga Brózda ◽  
Jacek Selejdak
Keyword(s):  
Crack Width ◽  
Computational Analysis ◽  
Concrete Beams ◽  
Limit State ◽  
Reinforced Concrete Beams ◽  
Design Guideline ◽  
Steel Bars ◽  
Steel Grades ◽  
Frp Reinforcement ◽  
Italian Design

The aim of the paper is to explain the particular problems related to the use of FRP reinforcement in bending beams. The paper compares the aspect of Serviceability Limit State (SLS) of simply supported concrete beams reinforced with Carbon Fiber Reinforced Polymer (CFRP) bars and three various types of steel bars (the steel grades are 35G2Y, 20G2VY-b and B500SP). The computational analysis of change in crack width under the influence of various level of service live load was investigated. The calculations of beam reinforced with FRP bars was based on Italian design guideline (CNR-DT 203/2006) and the conventional reinforced concrete beams (RC) were analysed in accordance with the European standard Eurocode 2 (EN 1992-1-1:2004).

Mechanical performance of CFRP enclosed reinforced concrete beams by different shear reinforcement

2020 ◽  
pp. 136943322097478
Author(s):  
Qi Cao ◽  
Jiadong Bao ◽  
Changjun Zhou ◽  
Xianrui Lv
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Mechanical Performance ◽  
Concrete Beams ◽  
Experimental Results ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Shear Reinforcement ◽  
Four Point Bending ◽  
Expansive Agent

This paper aims to study the flexural behavior of CFRP enclosed reinforced concrete beams with different shear reinforcement. Four-point bending tests were carried out on six concrete beams with different contents of steel fibers (0.5%, 1.0%, and 1.5%) as well as six beams with different stirrup spacing (100 mm, 150 mm, and 300 mm) without fiber. The effect of steel fiber (SF) content as well as stirrup spacing on flexural properties of concrete beams were investigated. Meanwhile, the effect of expansive agent on the properties of specimens was also studied. The data collected in this test include cracking load, ultimate load, mid-span deflection, strain of CFRP (Carbon fiber reinforced polymer), strain of longitudinal steel reinforcement as well as the failure modes. Test results show that both cracking loads and ultimate loads of the SF reinforced beam specimens are generally higher than those of the corresponding stirrup reinforced beam specimens. Experimental results also indicate that the addition of SF can improve the ductility and cracking resistance of specimens. This therefore demonstrates that it is feasible to replace stirrup reinforcement with SF as shear reinforcement. In addition, it exhibits a good agreement between experimental results and analytical predictions in cracking loads and ultimate loads.

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