scholarly journals CRACK ANALYSIS OF CFRP REINFORCED CONCRETE BEAMS UNDER SECONDARY LOADING

2021 ◽  
Vol 30 (4) ◽  
Author(s):  
Jinliang Liu ◽  
Jiawei Wang ◽  
Yanmin Jia

The paper established the calculation formulas on the average crack spacing and the maximum crack width of CFRP(Carbon Fiber Reinforced Polymer)reinforced concrete beam under the secondary loading. Conversion of CFRP plate area into the reinforcement ratio of the reinforced beam, the calculation formula on the average crack spacing of CFRP reinforced concrete beam under the secondary loading was established. On basis of the calculation formula on the maximum crack width of concrete beam, the calculation formula on the maximum crack width of CFRP reinforced concrete beam under the secondary loading was established. The average crack spacing and the maximum crack width calculated by the formulas in the paper were compared with the test data, it was verified that the formula is correct.

Author(s):  
Faisal Ananda ◽  
Agoes Soehardjono ◽  
Achfas Zacoeb ◽  
Gunawan Saroji

The classic theory mentions that the assessment of deflection and crack width should be taken to minimize those two behaviors. This research itself has the objective to examine whether the additional fiber steel and increased reinforcement ratio has any significant impact on the deflection and existing crack width. This test used the reinforced concrete beams with a size of 15 cm x 25 cm x 180 cm which placed on a simple pedestal. The test was done gradually in every 108 kg until the reinforced yield reached. The fiber increased from 0%, 1.57%, 3.14% and 4.71% while the performance rebar ratio increased from 2 # 10, 2 # 12, and 2 # 14. The result shows that additional 4.71% of maximum fiber decrease compressive strength and rupture modulus while the tensile strength increased. The additional fiber reached a maximum in 4.71% and the additional diameter of 10 mm, 12 mm, and 14 mm increased the deflections and crack width.


2013 ◽  
Vol 368-370 ◽  
pp. 1668-1673
Author(s):  
Zhi Hua Li ◽  
Xiao Zu Su

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.


2011 ◽  
Vol 368-373 ◽  
pp. 2094-2097
Author(s):  
Rui Ren ◽  
Jian Yang Xue ◽  
Zong Ping Chen ◽  
Ze Long Mi

8 channel steel reinforced concrete beams and 1 reinforced concrete beam are tested to study the capacity of channel steel reinforced concrete beam(CSRCB)under pure torque. The failure mode and process of the specimens are observed, And the working mechanism of channel steel skeleton and the concrete are analyzed. It is shown that the concrete strength, stirrup disposition and channel steel have significant effects on the torsional capacity of the beam. The calculation formula for torsional craze torque and ultimate torsional capacity of the CSRCB member are also proposed .


2017 ◽  
Vol 11 (1) ◽  
pp. 187-194
Author(s):  
Ruliang Zheng ◽  
Degao Tang ◽  
Yulong Xue ◽  
Zhen Liao

High-strength steel has increasingly become widely used among various engineering practices, but the relevant provisions of the codes lag behind its development. Six sets of experiments on simple supported beams reinforced with HTB600 and HTB700 rebars subject to bending loading were conducted in this study to 1) investigate the conditions of crack development, 2) contrast the calculating modes of short-term crack width between Chinese and European concrete codes, and 3) analyze European applicability and precision pertaining to high-strength reinforcement of beams. According to the experiments and research, when the calculation formulae obtained from Chinese codes were used to calculate the average crack spacing of high-strength reinforced concrete beams, the error relative to that obtained in the experiment reached approximately 20%. Based on this, a revised formula for the calculation of average crack spacing is proposed in this article, and the results of these calculations align with the results obtained from the experiment. In addition, this study also demonstrates that the maximum cracking spacing calculated by adhering to Eurocode standards yielded no significant deviation as compared to the experimental results. However, owing to a difference in the crack width exceeding 20% being observed between the results obtained under Eurocode standards and the experimental results, the calculation methods need to be further improved for better applicability of high-strength reinforced rebars.


2013 ◽  
Vol 663 ◽  
pp. 219-224
Author(s):  
Qi Yin Shi ◽  
Chun Zhao ◽  
Chun Wang ◽  
Qing Li

In this paper, the crack width and deflection of a local corroded reinforced concrete beam is investigated. The influence of the rebar corrosion on a concrete beam is analyzed first. Based on the constitutive relationship of the corroded reinforced concrete, the corroded reinforced concrete is regarded as a bond-slip composite beam which is comprised of corroded rebar and concrete. By using the large-scale finite element software ANSYS, a separate reinforced concrete beam model is developed after selecting the reasonable element. By using the proposed model, the positions of the cracks are determined. Moreover, the cracks width and the deflection of the beam at the corroded segment are calculated through using formula and extracting the results data from ANSYS. At last, the results by the standard design of concrete structures (GB50010-2010) and EN1992-1-1:2004[1] are compared through the list, which show the crack width and deflection of the local corroded reinforced concrete beams calculated by ANSYS is feasible.


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.


2011 ◽  
Vol 287-290 ◽  
pp. 1896-1901
Author(s):  
Zhi Kun Guo ◽  
Wan Xiang Chen ◽  
Qi Fan Wang ◽  
Yu Huang ◽  
Chao Pu Li ◽  
...  

The bearing capacities of one-way reinforced concrete beams with elastic supports are investigated in this paper. According to the nonlinear characteristics of the beams, the basic equations based on plastic theory of concrete are derived by considering the in-plane force effects that aroused by the constraints of supports when the beams deforming. It is indicated that the calculation results are in good agreement with experimental datum, and the influences of different supports on the bearing capacities of the beams are quantitatively given for the first time.


2020 ◽  
Vol 23 (9) ◽  
pp. 1934-1947
Author(s):  
Dapeng Chen ◽  
Li Chen ◽  
Qin Fang ◽  
Yuzhou Zheng ◽  
Teng Pan

The bending behavior of reinforced concrete beams under uniform pressure is critical for the research of the blast-resistance performance of structural components under explosive loads. In this study, a bending test of five reinforced concrete beams with the dimensions of 200 mm (width) × 200 mm (depth) × 2500 mm (length) under uniform load produced by a specific cylinder-shaped rubber bag filled with air or water was conducted to investigate their flexural performances. An air bag load was applied to three of the reinforced concrete beams, a water bag load was applied to one reinforced concrete beam, and the remainder beam was subjected to the 4-point bending load. The experimental results highlighted that the air bag and water bag loading methods can be used to effectively apply uniform loads to reinforced concrete beams. Moreover, the stiffness of the air bag was improved by 123% in accordance with the initial pressure increases from 0.15 to 0.45 MPa. In addition, a finite element model of the test loading system was established using ABAQUS/Standard software. Moreover, the critical factors of the air bag loading method were analyzed using the numerical model. The calculated results were found to be in good agreement with the test data. The established finite element model can therefore be used to accurately simulate the action performances of the uniform loading technique using rubber bags filled with air or water.


Author(s):  
S. O. Chepilko ◽  

Problems of taking into account nonlinear creep in steel- reinforced concrete beams are considered basing on the integral equation of viscous-elastic-plasticity of concrete. There has been obtained the resolving system of nonlinear integral equations, a linearization of this system has been carried out, its asymptotic solutions have been written out for the theory of elastic heredity case. The analysis of taking into account nonlinear creep has been performed compared with the linear creep equations and an instantaneous (short-term) loading allowing for concrete’s nonlinear diagram.


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