Effect of Materials Characteristics on Average Crack Spacing of Reinforced Concrete Specimen

2011 ◽  
Vol 704-705 ◽  
pp. 817-822
Author(s):  
Juan Xia Zhang ◽  
Xian Zhang Guo ◽  
Zheng Zhao Liang ◽  
Ya Fang Zhang
Keyword(s):  
Reinforced Concrete ◽  
Process Analysis ◽  
Concrete Strength ◽  
Failure Process ◽  
Numerical Test ◽  
Peak Load ◽  
Crack Spacing ◽  
Fracture Spacing ◽  
Average Crack ◽  
Initial Peak

The goal of the present work is to investigate the influence of concrete on failure mode and stress distribution of the reinforced concrete specimens under axial tension by using a numerical test code named Realistic Failure Process Analysis. It can be found that, the periodically distributed fracture spacing phenomenon and tension stiffening phenomenon exist in the failure process of the reinforced concrete structure. Besides, the effect of concrete characteristics on the mechanical behavior and crack spacing of reinforced concrete was also studied in three samples with different concrete strength. The concrete strength value is considered to be an important factor not only to significantly influence the average crack spacing but also to influence the initial peak load of the specimen. In addition, the average fracture spacing is increased and the initial peak load is also increase with the increasing of the concrete strength value, but the mechanical capacities of the concrete has little influence on the ultimate load capacities of the specimen. Keywords: Numerical test; reinforcement concrete, crack distribution, 3D

Stress Distribution Rule of Reinforced Concrete Specimen under Uniaxial Tension

2011 ◽  
Vol 117-119 ◽  
pp. 53-57
Author(s):  
Juan Xia Zhang ◽  
Xian Zhang Guo ◽  
Sheng Guang Zhuo ◽  
Chun An Tang
Keyword(s):  
Reinforced Concrete ◽  
Stress Distribution ◽  
Failure Process ◽  
Numerical Test ◽  
Concrete Specimen ◽  
Concrete Cover ◽  
Uniaxial Tensile ◽  
Fracture Spacing ◽  
Distribution Rule ◽  
Cover Thickness

A numerical test code named RFPA (Realistic Failure Process Analysis) was used to investigate the stress filed transformation process of the reinforced concrete specimen under uniaxial tensile loading. The periodically distributed fracture spacing phenomenon exists in the reinforced concrete structure and the concrete cover thickness was an important factor influence the average crack spacing and crack number. The numerical simulation results show that the stress fields on the concrete between the two adjacent cracks go through a variation process from tensile stress to compressive stress with the increasing of the concrete cover thickness value. It is clear that the stress distribution and fracture spacing were related to the concrete cover thickness under the condition that the materials characteristics were certain (such as concrete and reinforcement materials).In addition, if there was a new crack produced, the location was sure in the middle of the two adjacent cracks since the maximum stress occurred in the middle of the two adjacent cracks. So, it indicates that the concrete cover thickness can influence the average fracture spacing and the crack number in the reinforced concrete prism specimen.

Numerical Simulation of 3-D Failure Process of Reinforced Concrete Specimen under Uniaxial Tension

2007 ◽  
Vol 353-358 ◽  
pp. 949-952 ◽  
Author(s):  
Juan Xia Zhang ◽  
Chun An Tang ◽  
Xiu Yan Zhou ◽  
Xing Jie Hui ◽  
Zheng Zhao Liang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Reinforced Concrete ◽  
Uniaxial Tension ◽  
Process Analysis ◽  
Failure Process ◽  
Plain Concrete ◽  
Concrete Specimen ◽  
Numerical Code ◽  
Concrete Prism

The periodically distributed fracture spacing phenomenon exists in the failure process of the reinforced concrete prism under uniaxial tension. In this paper, A numerical code RFPA3D (3D Realistic Failure Process Analysis) is used to simulate the three-dimensional failure process of plain concrete prism specimen and reinforced concrete prism specimen under uniaxial tension. The reinforced concrete is represented by a set of elements with same size and different mechanical properties. They are uniform cubic elements and their mechanical properties, including elastic modulus and peak strength, are distributed through the specimens according to a certain statistical distribution. The elastic modulus and other mechanical properties are weakened gradually when the stresses in the elements meet the specific failure criterion. The displacement-controlled loading scheme is used to simulate the complete failure process of reinforced concrete. The analyses focus on the failure mechanisms of the concrete and reinforcement. The complete process of the fracture for the plain concrete prism and the fracture initiation, infilling and saturation of the reinforced concrete prism is reproduced. It agrees well with the theoretical analysis. Through 3D numerical tests for the specimen, it can be investigated the interaction between the reinforcement and concrete mechanical properties in meso-level and the numerical code is proved to be an effective way to help thoroughly understand the rule of the reinforcement and concrete and also help the design of the structural concrete components and systems.

REINFORCED CONCRETE CRACK MODEL BASED ON STIFFNESS ANALYSIS OF TENSION MEMBERS

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Angus Murray ◽  
Raymond Ian Gilbert ◽  
Arnaud Castel
Keyword(s):  
Reinforced Concrete ◽  
Numerical Study ◽  
Crack Spacing ◽  
Analytical Models ◽  
Crack Model ◽  
Primary Crack ◽  
Proposed Model ◽  
Average Crack ◽  
Service Behavior ◽  
Tension Members

The average spacing of primary cracks in a reinforced concrete (RC) member greatly influences its in-service behavior, especially with regard to stiffness and average crack width. Accurate predictions of the average crack spacing are therefore crucial for satisfying serviceability requirements in RC structures. This is particularly the case when relying on analytical models that treat cracks discretely rather than in a smeared fashion. Popular code-based models for primary crack spacing are often wildly inaccurate and may lead to poor predictions of in-service behavior. In this paper, the problem or primary crack formation is approached from a stiffness perspective. The proposed model is based on the results of several experimental tension stiffening studies in the literature, as well as a previous numerical study dealing with the effect on stiffness of non-plane deformation in the neighborhood of primary cracks. The proposed model is compared to some popular code-based models and is shown to better predict average crack spacing for a wide variety of beams, slabs, and tension members.

Numerical Investigation for Fracture Saturation in Multilayer Sedimentary Rock in Unsymmetrical Case

2013 ◽  
Vol 690-693 ◽  
pp. 3050-3053
Author(s):  
Feng Shan Han ◽  
Li Song
Keyword(s):  
Numerical Simulation ◽  
Layer Thickness ◽  
Sedimentary Rock ◽  
Process Analysis ◽  
Failure Process ◽  
Bottom Layer ◽  
Thickness Ratio ◽  
Fracture Spacing ◽  
Layer Thickness Ratio ◽  
Rock Failure Process

Opening mode fractures in multilayer sedimentary rock often are periodically distributed with fracture spacing scaled to the thickness of the fractured layer. In this paper, based on Rock Failure Process Analysis Code RFPA2D, a three layer model with a central layer and with the different thickness top and bottom layer, progressive formation in multilayer sedimentary rock at fracture saturation in unsymmetrical case is simulated. We investigate the change of the critical fracture spacing to layer thickness ratio as a function of the thickness of the top layer where the bottom layers is much thicker (5 times) than the fractured layer called the unsymmetrical case, in this unsymmetrical case, fracture saturation is simulated. By numerical simulation of RFPA2D, the critical spacing to layer thickness ratio decreases and tend to the same constant value as the thickness of the top layer increases. Numerical simulation shown that for the unsymmetrical case, if the adjacent layers are thicker than 1.5 times the thickness of the fractured layer, the multilayer sedimentary rock can be treated approximately as a system with infinitely thick top and bottom layers at fracture saturation.That should be useful in the design of engineering systems and in the prediction of fracture spacing in hydrocarbon reservoirs and groundwater aquifers.

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

2021 ◽  
Vol 30 (4) ◽  
Author(s):  
Jinliang Liu ◽  
Jiawei Wang ◽  
Yanmin Jia
Keyword(s):  
Reinforced Concrete ◽  
Crack Width ◽  
Concrete Beam ◽  
Reinforced Concrete Beam ◽  
Crack Spacing ◽  
Reinforced Concrete Beams ◽  
Calculation Formula ◽  
Plate Area ◽  
Average Crack ◽  
Maximum Crack

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.

Numerical Simulation of Crack Development in Reinforced Concrete Structures under Eccentric Loading

2005 ◽  
Vol 297-300 ◽  
pp. 2654-2659 ◽  
Author(s):  
Juan Xia Zhang ◽  
Junjie Liu ◽  
Chun An Tang ◽  
Xu Chang ◽  
Shu Hong Wang ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Process Analysis ◽  
Failure Process ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Reinforced Concrete Bridge ◽  
Initiation And Propagation ◽  
Three Phase ◽  
Lower Load ◽  
Mesoscopic Level

Reinforced concrete structures are generally designed to allow cracking under service loading. Accurate modeling of crack formation and propagation at lower load levels is therefore important. In this paper, a Material Failure Process Analysis code (MFPA2D) is used to model the crack initiation and propagation in reinforced concrete bridge pier subjected to eccentric loading. In our numerical model, the reinforced concrete is assumed to be a three-phase composite composed of concrete, reinforcement and interfaces between them. Numerically obtained results of cracking loads and global load-displacement response agree well with experimentally measured values. It has been found that the fracture of the concrete observed at the macroscopic level is predominated by tensile damage at the mesoscopic level.

scholarly journals Experimental Study on Calculation Methods for Short-term Cracks in High-strength Reinforced Concrete Beams

2017 ◽  
Vol 11 (1) ◽  
pp. 187-194
Author(s):  
Ruliang Zheng ◽  
Degao Tang ◽  
Yulong Xue ◽  
Zhen Liao
Keyword(s):  
Reinforced Concrete ◽  
Crack Width ◽  
Concrete Beams ◽  
High Strength ◽  
Crack Spacing ◽  
Experimental Results ◽  
Reinforced Concrete Beams ◽  
Calculation Methods ◽  
Short Term ◽  
Average Crack

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.

Failure Behavior Numerical Test of Empress All-Ceramic Crowns

2013 ◽  
Vol 699 ◽  
pp. 476-479
Author(s):  
Cheng Fan
Keyword(s):  
Process Analysis ◽  
Failure Process ◽  
Numerical Test ◽  
Damage Mechanism ◽  
Failure Behavior ◽  
Dimensional Model ◽  
All Ceramic ◽  
Ceramic Crowns ◽  
Analysis System ◽  
Ceramic Crown

All-ceramic crown restorations are more widely used, however the brittleness of ceramics and stress mismatch of porcelain interlaminar often leads to damage of all-ceramic crown, and damage mechanism is not very clear. In this paper, a two dimensional model of Empress all-ceramic crowns is constructed using the RFPA (realistic failure process analysis) system to simulate the fracture process and analysis the fracture mechanism. The most advantage of this system is that the crack initiation, propagation and failure process of all-ceramic crown can be clearly observed and the research results provide guidance for clinical application.

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