scholarly journals Experimental study of a rehabilitation solution that uses GFRP bars to replace the steel bars of reinforced concrete beams

2016 ◽  
Vol 128 ◽  
pp. 166-183 ◽  
Author(s):  
Patrícia Escórcio ◽  
Paulo M. França
2016 ◽  
Vol 845 ◽  
pp. 132-139
Author(s):  
Mochamad Teguh ◽  
Novia Mahlisani

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.


Author(s):  
Tales Viebrantz Fernandes ◽  
Aline Ribeiro Paliga ◽  
Charlei Marcelo Paliga

abstract: There is a recurring need to construct in places where environmental aggressiveness is very high, such as tidal-splash sites, chemical industries, etc. In these places, steel bars, commonly used for concrete reinforcement, can suffer deterioration, losing cross-sectional area and consequently the resistant capacity. In this regard, Glass Fiber Reinforced Polymers (GFRP) bars can replace steel because of its high strength to harsh environments, low weight and high tensile strength. Thus, this work aimed to compare reinforced concrete beams with steel bars and GFRP bending bars using the procedures indicated in ABNT:NBR 6118 and ACI 440.1R-15, respectively. Experimental three-point flexural tests were performed on six concrete beams, three reinforced with steel bars and three reinforced with GFRP bars. The beams were designed for centered point loads of 23.5 kN, 37.5 kN and 57 kN, and for each load one beam was reinforced in steel and one in GFRP. As main conclusions, it can be said that the beams reinforced with GFRP bars presented greater transverse displacements due to the low modulus of elasticity of this material. In addition, the beams presented rupture loads close to each design load, showing agreement in the recommendations of the two normative documents. Comparing the maximum loads of steel and GFRP beams, ratios of +9.3%, -3.2% and -3% were obtained for beams designed for 23.5 kN, 37.5 kN and 57 kN, respectively. Also, that variations in design loads cause greater variation in the longitudinal reinforcement rate of GFRP bar-beams compared to steel-bar beams.


2021 ◽  
pp. 136943322110015
Author(s):  
Akram S. Mahmoud ◽  
Ziadoon M. Ali

When glass fibre-reinforced polymer (GFRP) bar splices are used in reinforced concrete sections, they affect the structural performance in two different ways: through the stress concentration in the section, and through the configuration of the GFRP–concrete bond. This study experimentally investigated a new method for increasing the bond strength of a GFRP lap (two GFRP bars connected together) using a carbon fibre-reinforced polymer (CFRP) sheet coated in epoxy resin. A new splicing method was investigated to quantify the effect of the bar surface bond on the development length, with reinforced concrete beams cast with laps in the concrete reinforcing bars at a known bending span length. Specimens were tested in four-point flexure tests to assess the strength capacity and failure mode. The results were summarised and compared within a standard lap made according to the ACI 318 specifications. The new method for splicing was more efficient for GFRP splice laps than the standard lap method. It could also be used for head-to-head reinforcement bar splices with the appropriate CFRP lapping sheets.


Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3255 ◽  
Author(s):  
Fang Yuan ◽  
Mengcheng Chen

Fibre-reinforced polymer (FRP)-reinforced concrete members exhibit low ductility due to the linear-elastic behaviour of FRP materials. Concrete members reinforced by hybrid FRP–steel bars can improve strength and ductility simultaneously. In this study, the plastic hinge problem of hybrid FRP–steel reinforced concrete beams was numerically assessed through finite element analysis (FEA). Firstly, a finite element model was proposed to validate the numerical method by comparing the simulation results with the test results. Then, three plastic hinge regions—the rebar yielding zone, concrete crushing zone, and curvature localisation zone—of the hybrid reinforced concrete beams were analysed in detail. Finally, the effects of the main parameters, including the beam aspect ratio, concrete grade, steel yield strength, steel reinforcement ratio, steel hardening modulus, and FRP elastic modulus on the lengths of the three plastic zones, were systematically evaluated through parametric studies. It is determined that the hybrid reinforcement ratio exerts a significant effect on the plastic hinge lengths. The larger the hybrid reinforcement ratio, the larger is the extent of the rebar yielding zone and curvature localisation zone. It is also determined that the beam aspect ratio, concrete compressive strength, and steel hardening ratio exert significant positive effects on the length of the rebar yielding zone.


2012 ◽  
Vol 535-537 ◽  
pp. 1803-1806
Author(s):  
Shun Bo Zhao ◽  
Peng Bing Hou ◽  
Fu Lai Qu

An experimental study was carried out to examine the non-uniform corrosion of plain steel bars in reinforced concrete beams partially placed in 5% sodium chloride solution under conditions of accelerated corrosion. 4 reinforced concrete beams with different concrete strength were made. The crack distributions of the beams due to pre-loads and expansion of corrosion product, and the sectional corrosion characteristics of plain steel bars are described in detail. The sectional area loss relating to mass loss and change along pure bending length of the beams are discussed. These can be used as the basis of test for further studies to build the numerical models of serviceability of corroded reinforced concrete beams.


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