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![Figure 2.1: FRP bars with rough surface (Sand-coated FRP bars) from [48]](profile/Mar-Pub/publication/361038930/figure/fig1/AS:1162565761662979@1654188685494/FRP-bars-with-rough-surface-Sand-coated-FRP-bars-from-48_Q320.jpg)
![Figure 4.3: Uniaxial tensile behavior of concrete. Reproduction from [34]](profile/Mar-Pub/publication/361038930/figure/fig2/AS:1162565761679361@1654188685512/Uniaxial-tensile-behavior-of-concrete-Reproduction-from-34_Q320.jpg)
![Figure 4.6: Hyperbolic plastic flow rule. Reproduction from [34]](profile/Mar-Pub/publication/361038930/figure/fig3/AS:1162565761667072@1654188685529/Hyperbolic-plastic-flow-rule-Reproduction-from-34_Q320.jpg)
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... Two constitutive material models for analyzing concrete are available in ABAQUS/Standard: concrete smeared-cracking (CSC) and concrete damaged plasticity (CDP) models [15]. The CDP algorithms derived by Alfarah et al. [16] were used to develop the inelastic stress-strain concrete response in compression and tension. ...
... Higher values of μ increase the damage zone [18], while lower values may cause convergence issues in the ABAQUS solver [13]. For eccentricity (∊), f b0 /f c0 , and K C , the ABAQUS default values of ∊ = 0.1, f b0 /f c0 = 1.16, and K C = 2/3 were used in all CDP models surveyed [9,10,13,15,16,[18][19][20]. Table 2 summarizes values selected by different researchers for modelling concrete pipe. ...
Reinforced Concrete Pipe (RCP) is widely used in storm and wastewater management owing to its resiliency and reliability. This study proposes nonlinear 3D finite-element models (FEMs) to explore the effects of reinforcement configuration on RCP structural performance. RCP having 825-mm, 1200-mm, and 1800-mm in diameter with the three reinforcement configurations commonly used by industry, namely single-cage, double-cage, and triple-cage, were modelled for evaluating 65D, 100D, and 140D pipe design classes. FEM predicted load-deflection was validated using experimental results on full-scale RCP specimens. Average FEM prediction error of service and ultimate loads was 6.8% and 6.3%, respectively. FEM stress contours suggested agreement with experimental observations. The development of stress in the concrete and steel reinforcement during the there-edge bearing test (TEBT) was evaluated and discussed. A thorough parametric analysis was performed on developed single and double-cage FEMs and demonstrated that the influence of the reinforcement area, cover, positioning, and yield strength on RCP behavior could be rationally captured by the numerical models.
... The failure mode for the beams reinforced with FRP bars was for the materials and elements. Also, it has the ability to contact between solids [93]. ...
The performance and behavior of concrete composite continuous beams that consisting of normal concrete and Slurry Infiltrated Fiber Concrete (SIFCON) is investigated in this research. Also, the present study aims to examine the effectiveness of using hybrid reinforcement (steel and FRP or different types of FRP bars) instead of using steel bars alone to reinforce concrete composite continuous beams under static and repeated loads.
The experimental program included the study of thirteen T-section continuous beams for flexure to discuss the effect of using SIFCON at compression or tension of plastic zones, volume fraction of steel fiber in SIFCON, using of CFRP, GFRP bars as main reinforcement, hybrid main reinforcement and repeated loads (20 cycles of 70% from the ultimate capacity and then loaded up to failure) on the behavior of T- section composite continuous beams. The study focused on the determination of the ultimate flexural capacity, load- deflection relation, moment redistribution, toughness, first crack load, crack width development, failure mode, stain distribution through the depth for critical sections and crack pattern at failure stage. Digital Image Correlation (DIC) technique which is a non-contact measurement system was used successfully to evaluate the strains.
It was noticed experimentally that the using of SIFCON at plastic zone (specially at compression parts of the plastic zones) has a significant effect on the structural response of continuous composite concrete beams. However, There is an average of (15,20 and16) % increase in flexural capacity of composite beams with steel fiber volumetric ratio of (7, 9 and 11)% respectively compared to the normal concrete beam. While the development in the moment redistribution for composite beams were approximately 62% , 104% and 41%, when SIFCON used with volumetric ratio 7%, 9% and 11% respectively comparing with the reference beam(normal concrete beam).
The experimental results also show that the using of FRP bars as main reinforcement led to a decrease in the energy absorption at failure load for continuous beams; consequently, the toughness reduced by approximately 16.5%, 19% and 15% for beams that reinforced with glass, hybrid of glass-carbon and hybrid of steel-carbon respectively comparing with the reference beam. However, the minimum reduction in beam flexural strength when it exposed to repeated loads in comparison with that under static loads was noticed in composite continuous beams (with SIFCON at compression part of P.H. zones) which reinforced by steel and hybrid reinforcement (CFRP-steel) by about 0.6% and 0.4% respectively. While, this reduction in flexural strength was increased to 4% for reference beam.
A system computer program (ABAQUS 6.13) is used to simulate a finite element model suitable for the analysis of continuous composite concrete beams. So as to check the validity and accuracy of the simulated model, various continuous beams were chosen from experimental specimens. It is found that there is a good convergence state between experimental and ABAQUS results. The higher percentage difference in ultimate flexural capacity was less than 7%. While the biggest difference in maximum deflection values between the theoretical and practical results was not to exceed (21%). Moreover, the effect of some important factors on the composite continuous beams behavior were investigated through the numerical simulated model. Where, type of loading, variables the amounts of repeated load values and using BFRP as main reinforcement were the considered parameters. The results show that BFRP bars can be used to reinforced the composite continuous beams as hybrid reinforcement with steel bars as the best chose of FRP bars types. Also, the results show the clear positive effect of the use of the SIFCON in the composite beams by reducing the value of the deterioration in the resistance of the these beams when increasing the repeated loading rate compared to the reference beam.
... This technique was used a lot before by Obaidat et al. 22 and Hamedani and Esfahani. 23 The fracture energy G f depends on the concrete quality and aggregate size, and it can be obtained from CEB-FIP. 24 Figure 12 illustrates the simplified considered tensile curve of the concrete. ...
In the current research, an experimental program, consisting of one straight beam and seven stepped beams (SBs), is to be carried out. Furthermore, a numerical validation is to be applied using finite element analysis. The effect of the additional vertical and horizontal stirrups, the diagonal bars, the configuration of the tension bars, and the inclination angle of the stepped joint on the behavior of the SB is to be examined. Moreover, the influence of the width and the drop of the stepped joint on the behavior of the SB is to be induced. Compared with the straight beam, the ratios of the ultimate load decrease of the SB ranged from −64.23% to 0.00%. On the one hand, as the joint drop increases, the ultimate load of the SB decreases. On the other hand, when the joint width increases, the ultimate load of the SB increases. Many proposed techniques in reinforcing and dimensions of the stepped part have increased the flexural capacity. Proposed equations of the flexural capacity of the SB are to be induced after examination, taking into consideration the required parameters of the stepped beams, such as the compressive strength of the concrete, the tension and the compression steel, the dimension of the beam section, the horizontal stirrups, the diagonal bars, or the width and the drop of the stepped joint.
Precast concrete structures have been widely used in the construction industry. This is due to the reduction of time and labor cost in construction of concrete building structures. Strength and ductility of connection of the precast element must be adequately designed to prevent failure of connection prior to failure of members. Experiments performed by previous researchers were done to proof the strength stiffness and ductility of beam-column connection but high cost and time consuming. In this work, the nonlinear finite element model was developed to analyze the behaviors of reinforced concrete beam-column connection of precast concrete structures. The model was verified by the experimental results performed by the previous work. It was found a good correlation between test and analytical results.
Abstract. This analytical study aims to investigate the flexural behavior of simply supported RC
beams having longitudinal hole with circle cross section under monotonic two point loads. The
commercial FE program ABAQUS was used for simulating and implementing the specimens
behavior that tested experimentally in previous researches. The overall specimens investigated
were thirteen RC rectangular beam specimen, the first one was solid while the others with
longitudinal circular hole. The specimens with holes divided into three groups, each one has a
specified hole diameter 25 mm, 40 mm, and 50 mm. The distance from center of hole to the top
section face was variable where the hole would be completely in the stress block, below it, or
partially within it. The validity of the simulated model were verified by comparing the available
load deflection data with the implemented one, where good agreement were noticed. The
simulated models could introduce the ultimate load, first cracking load and its propagation in
addition to the maximum attended deflection. It is concluded that the existence of a longitudinal
hole with a percentage of diameter to beam depth ratio below 20% with different positions from
top surface of the cross-section to the center of the hole values caused decreasing in ultimate
load not exceeding 5% compared with the solid beam.
Keywords: Small longitudinal opening, deflection, first
Precast concrete structures have been widely used in the construction industry. This is due to the reduction of time and labor cost in construction of concrete building structures. Strength and ductility of connection of the precast element must be adequately designed to prevent failure of connection prior to failure of members. Experiments performed by previous researchers were done to proof the strength stiffness and ductility of beam-column connection but high cost and time consuming. In this work, the nonlinear finite element model was developed to analyze the behaviors of reinforced concrete beam-column connection of precast concrete structures. The model was verified by the experimental results performed by the previous work. It was found a good correlation between test and analytical results.
Artificial neural networks (ANN) were used in this study to predict ultimate load of simply supported concrete beams reinforced with FRP bars under four point loading. A proposed neural model was used to predict the ultimate load of these beams. A total number of (199) beams (samples) were collected as data set and it was decided to use eight input variables, representing the dimensions of beams and properties of concrete and FRP bars, while the output variable was only the ultimate load of these beams. It was found that the use of 11 and 10 nodes in the two hidden layers was very efficient for predicting the ultimate load. The obtained results were compared with available experimental results and with the ACI 440.1R specifications. The proposed neural model gave very good predictions and more accurate results than the ACI 440.1R approach. The overall average error, in the value of the predicted ultimate load, was 3.6% and 21.7% for the proposed neural model and the ACI 440.1R approach, respectively.
