scholarly journals Scaled Approach to Designing the Minimum Hybrid Reinforcement of Concrete Beams

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5166
Author(s):  
Andrea Gorino ◽  
Alessandro Fantilli

To study the brittle/ductile behavior of concrete beams reinforced with low amounts of rebar and fibers, a new multi-scale model is presented. It is used to predict the flexural response of an ideal Hybrid Reinforced Concrete (HRC) beam in bending, and it is validated with the results of a specific experimental campaign, and some tests available in the technical literature. Both the numerical and the experimental measurements define a linear relationship between the amount of reinforcement and the Ductility Index (DI). The latter is a non-dimensional function depending on the difference between the ultimate load and the effective cracking load of a concrete beam. As a result, a new design-by-testing procedure can be established to determine the minimum reinforcement of HRC elements. It corresponds to DI = 0, and can be considered as a linear combination of the minimum area of rebar (of the same reinforced concrete beam) and the minimum fiber volume fraction (of the same fiber-reinforced concrete beam), respectively.

2011 ◽  
Vol 243-249 ◽  
pp. 1058-1061
Author(s):  
Jun Wang ◽  
Huan Jun Ye ◽  
Zhi Wei Sun ◽  
Wei Chen

In order to research the influence of basalt fiber on the crack and deflection of the reinforced concrete beams, four basalt fiber reinforced concrete beams with the key parameters of length which were 12mm and 30mm and volume ratio which were 0.1% and 0.2% were designed and made. The test data was obtained through the bending experiment and the comparison with the common reinforced concrete beam. The result shows that it is obvious to control the crack and deflection of the test beams with the increasing of basalt fiber characteristic parameters. The calculation method of the maximum crack width of the basalt fiber reinforced concrete beams were presented based on the method of common concrete beam, which can provide the theoretical basis for the engineering practice.


2014 ◽  
Vol 584-586 ◽  
pp. 899-903
Author(s):  
Wei Chen ◽  
Xiang Peng Li ◽  
Ting Ting Chen ◽  
Xiao Yang Wang ◽  
Chao Chao Ma

In order to research the influence of the shear capacity of reinforced concrete beam with the incorporation of basalt fiber, four basalt fiber reinforced concrete beams with parameters of length and volume ratio were designed and made. The fiber lengths were 12mm and 30mm, and the volume ratios were 1‰ and 2‰. The test data of basalt fiber reinforced concrete was obtained through the shear experiments and comparison with the common reinforced concrete beam. The results of the experiment show that the cracking load of the basalt fiber reinforced concrete beam increase obviously with the growing of fiber characteristic parameters, and effectively reduce the diagonal crack width.


2019 ◽  
Vol 9 (1) ◽  
pp. 4-9
Author(s):  
Sergey S. MORDOVSKY ◽  
Nikolay A. ILYIN ◽  
Denis A. PANFILOV ◽  
Valeriya N. TALANOVA ◽  
Yana A. BUZOVSKAYA

The article presents a new technical solution, which relates to the field of construction, in particular, to the testing of bending reinforced concrete elements - building beams for strength, deformation and fire resistance on a scale model. The new method of solution implies an increase in the information content, visual clarity and depth of experimental studies of reinforced concrete beams as a result of using the cost-effective way of designing geometric and forceful similarity to the scale model of reinforced concrete beams for strength, deformation and fire resistance. The proposed method allows us to estimate the limiting states of a reinforced concrete beam by strength, deformation and fire resistance; develop an analytical model for calculating the actual fire resistance; save on labor costs in the manufacture of large scale model of full scale design for its testing.


2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Xia Zhao ◽  
Xiong-Jun He ◽  
Yong-Chao Yang

Experiment on the constitutive model of fiber reinforced concrete with volume fraction of alkali-resistant glass fiber of, respectively, 0.0%, 0.5%, 1.0%, and 1.5% was conducted, and the constitutive relation of tension stress-strain full curve of GFRC shaft was obtained; the constitutive relation of GFRP is obtained by experiment, and the secant modulus was obtained by the fitting of univariate cubic equation. The finite element numerical simulation of GFRP fiber reinforced concrete beam was carried out, and the load deflection nephogram of fiber reinforced concrete beam, strain nephogram, crack nephogram, and GFRP stress nephogram were obtained. When the fiber content is 1.0%, the bearing capacity of GFRP reinforced concrete beams is the best, and it could play a “bridging” effect when the incorporation of fiber is within the load range of about 60%, which inhibited the developing speed of cracks, but with the gradual increase of the load, the “bridging” effect disappeared.


2011 ◽  
Vol 243-249 ◽  
pp. 756-760
Author(s):  
Qin Xu ◽  
Wei Huang ◽  
Hao Zhen Wu ◽  
Xiao Ping Jiang ◽  
Zhen Zhong Zhang

Based on bending fiber reinforced concrete beam, through the nonlinear analysis, the paper discuss the constitutive models of concrete and reinforcement, the properties of their element and the models of concrete beams reinforced with FRP bars. Using nonlinear analysis and comparing numerical results with experimental results, the fiber reinforced concrete beam bending terminal numerical model constructed in this paper can simulate the entire process of internal force and deformation of fiber reinforced concrete beams, and describe cracks in the formation and extension and the failure process and failure form, which also can provide enough precision to the practical engineering and scientific research. Meanwhile, the finite element computation model verified by test can provide more reactive information to effective structure computation model.


2010 ◽  
Vol 168-170 ◽  
pp. 2037-2043
Author(s):  
Yin Gu ◽  
Wei Dong Zhuo ◽  
Yu Ting Qiu

This paper proposes a concept of layered fiber reinforced concrete (LFRC) beam. In the concept of a LFRC beam, low-modulus fiber and high-modulus fiber are randomly dispersed and uniformly distributed into the concrete matries of the compression and tension zones, respectively. The static behaviors of LFRC beam are investigated from both experimental and numerical aspects. Four-point bending tests are performed on two simply supported T-shaped LFRC beam specimens and an ordinary T-shaped RC beam specimen with large scales. Comparison between the testing results of LFRC and RC beam specimens shows that the initial cracking load, flexural toughness and post-yielding stiffness of a LFRC beam can be significantly improved, but the ultimate loads are nearly without change. Numerical simulations are also carried out to investigate the static behaviors of the LFRC beam specimens. It is found that the simulation results are agreed well with that of tests. Further numerical parameter analysis for the LFRC beam specimens is conducted. The effects of high-modulus fiber volume fraction on the static behaviors of LFRC beams are studied. The research results show that the additions of high-modulus fibers have little effect on the initial stiffness, yielding loads and ultimate loads of LFRC beams; both the load and displacement at the initial cracking point increase linearly with the increasing volume fraction of the high-modulus fiber, but both the yielding displacement and ultimate displacement decrease linearly with the increasing volume fraction of the high-modulus fiber.


2018 ◽  
Vol 21 (13) ◽  
pp. 1977-1989 ◽  
Author(s):  
Tengfei Xu ◽  
Jiantao Huang ◽  
Arnaud Castel ◽  
Renda Zhao ◽  
Cheng Yang

In this article, experiments focusing at the influence of steel–concrete bond damage on the dynamic stiffness of cracked reinforced concrete beams are reported. In these experiments, the bond between concrete and reinforcing bar was damaged using appreciate flexural loads. The static stiffness of cracked reinforced concrete beam was assessed using the measured load–deflection response under cycles of loading and unloading, and the dynamic stiffness was analyzed using the measured natural frequencies with and without sustained loading. Average moment of inertia model (Castel et al. model) for cracked reinforced beams by taking into account the respective effect of bending cracks (primary cracks) and the steel–concrete bond damage (interfacial microcracks) was adopted to calculate the static load–deflection response and the natural frequencies of the tested beams. The experimental results and the comparison between measured and calculated natural frequencies show that localized steel–concrete bond damage does not influence remarkably the dynamic stiffness and the natural frequencies both with and without sustained loading applied. Castel et al. model can be used to calculate the dynamic stiffness of cracked reinforced concrete beam by neglecting the effect of interfacial microcracks.


2012 ◽  
Vol 214 ◽  
pp. 306-310
Author(s):  
Han Chen Huang

This study proposes a artificial neural network with genetic algorithm (GA-ANN) for predicting the torsional strength of reinforced concrete beam. Genetic algorithm is used to the optimal network structure and parameters. A database of the torsional failure of reinforced concrete beams with a rectangular section subjected to pure torsion was obtained from existing literature for analysis. This study compare the predictions of the GA-ANN model with the ACI 318 code used for analyzing the torsional strength of reinforced concrete beam. The results show that the proposed model provides reasonable predictions of the ultimate torsional strength of reinforced concrete beams and offers superior torsion accuracy compared to that of the ACI 318-89 equation.


2006 ◽  
Vol 33 (6) ◽  
pp. 726-734 ◽  
Author(s):  
Fariborz Majdzadeh ◽  
Sayed Mohamad Soleimani ◽  
Nemkumar Banthia

The purpose of this study was to investigate the influence of fiber reinforcement on the shear capacity of reinforced concrete (RC) beams. Both steel and synthetic fibers at variable volume fractions were investigated. Two series of tests were performed: structural tests, where RC beams were tested to failure under an applied four-point load; and materials tests, where companion fiber-reinforced concrete (FRC) prisms were tested under direct shear to obtain material properties such as shear strength and shear toughness. FRC test results indicated an almost linear increase in the shear strength of concrete with an increase in the fiber volume fraction. Fiber reinforcement enhanced the shear load capacity and shear deformation capacity of RC beams, but 1% fiber volume fraction was seen as optimal; no benefits were noted when the fiber volume fraction was increased beyond 1%. Finally, an equation is proposed to predict the shear capacity of RC beams.Key words: shear strength, fiber-reinforced concrete, RC beam, stirrups, energy absorption capacity, steel fiber, synthetic fiber.


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