scholarly journals A Practical Finite Element Modeling Strategy to Capture Cracking and Crushing Behavior of Reinforced Concrete Structures

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 506 ◽  
Author(s):  
Alexandre Mathern ◽  
Jincheng Yang
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Constitutive Relations ◽  
Fe Analysis ◽  
Rc Beams ◽  
Cracking Behavior ◽  
Concrete Cracking ◽  
Rc Structures ◽  
Nonlinear Fe Analysis ◽  
Modeling Strategy

Nonlinear finite element (FE) analysis of reinforced concrete (RC) structures is characterized by numerous modeling options and input parameters. To accurately model the nonlinear RC behavior involving concrete cracking in tension and crushing in compression, practitioners make different choices regarding the critical modeling issues, e.g., defining the concrete constitutive relations, assigning the bond between the concrete and the steel reinforcement, and solving problems related to convergence difficulties and mesh sensitivities. Thus, it is imperative to review the common modeling choices critically and develop a robust modeling strategy with consistency, reliability, and comparability. This paper proposes a modeling strategy and practical recommendations for the nonlinear FE analysis of RC structures based on parametric studies of critical modeling choices. The proposed modeling strategy aims at providing reliable predictions of flexural responses of RC members with a focus on concrete cracking behavior and crushing failure, which serve as the foundation for more complex modeling cases, e.g., RC beams bonded with fiber reinforced polymer (FRP) laminates. Additionally, herein, the implementation procedure for the proposed modeling strategy is comprehensively described with a focus on the critical modeling issues for RC structures. The proposed strategy is demonstrated through FE analyses of RC beams tested in four-point bending—one RC beam as reference and one beam externally bonded with a carbon-FRP (CFRP) laminate in its soffit. The simulated results agree well with experimental measurements regarding load-deformation relationship, cracking, flexural failure due to concrete crushing, and CFRP debonding initiated by intermediate cracks. The modeling strategy and recommendations presented herein are applicable to the nonlinear FE analysis of RC structures in general.

Probabilistic Design for Deteriorating Reinforced Concrete Structures with Time-Variant Finite Element Analysis

2019 ◽  
Author(s):  
Tsuyoshi Kouta ◽  
Christian Bucher
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Structural Reliability ◽  
Fe Analysis ◽  
Structural Safety ◽  
Illustrative Case ◽  
Probabilistic Design ◽  
Element Analysis ◽  
Rc Structures ◽  
Chloride Induced Corrosion

<p>In this study, a probabilistic design method using time-variant three-dimensional finite element (FE) analysis is presented to predict the structural reliability of deteriorating reinforced concrete (RC) structures due to chloride-induced corrosion. First, models of probabilistic corrosion due to chloride-induced corrosion are briefly reviewed. Then, FE modeling methods for corroded RC structures are presented, followed by validation with reference to experimental tests. In the methods, concrete and reinforcing steels are separately modeled, and the degradation in mechanical behavior of both components is considered. Finally, as an illustrative case study for the proposed FE analysis, the time-variant structural safety of a box-girder bridge is calculated over its lifetime of 50 yrs. The results of this study indicate that the proposed methods can be used to estimate the long-term structural safety of deteriorating RC structures.</p>

A comprehensive nonlinear finite element modelling and parametric analysis of reinforced concrete beams

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Pandimani Pandimani ◽  
Markandeya Raju Ponnada ◽  
Yesuratnam Geddada
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Reinforced Concrete ◽  
Ultimate Load ◽  
Fe Analysis ◽  
Fe Model ◽  
Rc Beams ◽  
Content Type ◽  
Bond Slip ◽  
Slip Mechanism

Purpose This study aims to present comprehensive nonlinear material modelling techniques and simulations of reinforced concrete (RC) beams subjected to short-term monotonic static load using the robust and reliable general-purpose finite element (FE) software ANSYS. A parametric study is carried out to analyse the flexural and ductility behaviour of RC beams under various influencing parameters. Design/methodology/approach To develop and validate the numerical FE models, a total of four experimentally tested simply supported RC beams are taken from the available literature and two beams are selected from each author. The concrete, steel reinforcements, bond-slip mechanism, loading and supporting plates are modelled using SOLID65, LINK180, COMBIN39 and SOLID185 elements, respectively. The validated models are then used to conduct parametric FE analysis to investigate the effect of concrete compressive strength, percentage of tensile reinforcement, compression reinforcement ratio, transverse shear reinforcement, bond-slip mechanism, concrete compressive stress-strain constitutive models, beam symmetry and varying overall depth of beam on the ultimate load-carrying capacity and ductility behaviour of RC beams. Findings The developed three-dimensional FE models can able to capture the load and midspan deflections at critical points, the accurate yield point of steel reinforcements, the formation of initial and progressive concrete crack patterns and the complete load-deflection curves of RC beams up to ultimate failure. From the numerical results, it can be concluded that the FE model considering the bond-slip effect with Thorenfeldt’s concrete compressive stress-strain model exhibits a better correlation with the experimental data. Originality/value The ultimate load and deflection results of validated FE models show a maximum deviation of less than 10% and 15%, respectively, as compared to the experimental results. The developed model is also capable of capturing concrete failure modes accurately. Overall, the FE analysis results were found quite acceptable and compared well with the experimental data at all loading stages. It is suggested that the proposed FE model is a practical and reliable tool for analyzing the flexural behaviour of RC members and can be used for performing parametric studies.

Repair of Severely Damaged Reinforced Concrete Beams with High-Strength Cementitious Grout

2020 ◽  
Vol 2674 (6) ◽  
pp. 372-384
Author(s):  
Antoine N. Gergess ◽  
Mahfoud Shaikh Al Shabab ◽  
Razane Massouh
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Cementitious Materials ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Rc Structures

High-strength cementitious materials such as high-performance concrete are extensively used for retrofit of reinforced concrete (RC) structures. The effectiveness of these materials is increased when mixed with steel fibers. A commonly used technique for strengthening and repair of RC beams consists of applying high-performance fiber-reinforced concrete jackets around the beam perimeter. This paper investigates the jacketing method for repairing severely damaged RC beams. Four 2 m (6 ft 63/4 in.) long rectangular RC beams, 200 × 300 mm (8 ×12 in.) were initially cast and loaded until failure based on three-point bending tests. The four beams were then repaired by thickening the sides of the damaged RC beams using a commercially available high-strength shrinkage grout with and without steel fibers. Strain and deformation were recorded in the damaged and repaired beams to compare structural performance. It is shown that the flexural strength of the repaired beams is increased and the crack pattern under loading is improved, proving that the proposed repair method can restore the resistance capacity of RC beams despite the degree of damage. A method for repair is proposed and an analytical investigation is also performed to understand the structural behavior of the repaired beams based on different thickening configurations.

Finite Element Analysis of Shear Strength of Reinforced Concrete Beams after Fire

2013 ◽  
Vol 671-674 ◽  
pp. 474-478 ◽  
Author(s):  
Kai Xiang ◽  
Guo Hui Wang ◽  
Bi Zhao
Keyword(s):  
Finite Element ◽  
Shear Strength ◽  
Reinforced Concrete ◽  
Exposure Time ◽  
Concrete Strength ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Fire Exposure ◽  
Shear Span ◽  
Strength And Stiffness

Shear strength and stiffness of fire-damaged reinforced concrete (RC) beams were researched. The nonlinear finite element method (FEM) was developed to simulate shear strength of fire-damaged RC beams. Considering mechanical properties deterioration of concrete and steel reinforcing bar, the parameters of fire-damaged RC beams, including fire exposure time, shear span to depth ratios, concrete strength, diameters of stirrups and spacing of stirrups, were analyzed. Based on numerical analysis, the change of shear strength and stiffness of fire-damaged RC beams were identified. The results showed that shear strength and stiffness of fire-damaged RC beams changed under different parameters. With increase of fire exposure time or increase of shear span to depth ratio or decrease of concrete strength, shear strength and stiffness of fire-damaged RC beams descended obviously. With decrease of diameters of stirrups or increase of spacing of stirrups, shear strength of fire-damaged RC beams descended gradually, but stiffness of fire-damaged RC beams had little change.

FINITE ELEMENT MODELLING OF 2-SPAN CONTINUOUS RC BEAMS SHEAR STRENGTHENED AND SHEAR REPAIRED WITH CFRP STRIPS

2016 ◽  
Vol 78 (5) ◽  
Author(s):  
Abdul Aziz Abdul Samad ◽  
Noorwirdawati Ali ◽  
Noridah Mohamad ◽  
J. Jayaprakash ◽  
Tuan Duc Ngo ◽  
...  
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Shear Behaviour ◽  
Rc Beams ◽  
Shear Strengthening ◽  
Existing Structures ◽  
Finite Element Software ◽  
Externally Bonded ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer

Strengthening of reinforced concrete (RC) continuous beams in shear have received very little attention among researchers even though most existing structures are in the form of continuous condition such as part of a floor-beam system. Therefore, in order to address the gap, a study on shear strengthening and shear repair of reinforced concrete continuous beam using Carbon Fibre Reinforced Polymer (CFRP) strips was conducted [15].  The validation of the experimental results was conducted with a simulation study using a finite element software ATENA v4 [16].  The research variables were number of layers of CFRP strips (one or two layers), wrapping schemes (four sides or three sides) and orientation of CFRP strips (0/90 or 45/135 degree’s). From the analysis of the finite element results, ATENA shows it has successfully simulated the shear behaviour of strengthened and repaired of 2-span continuous RC beams externally bonded by CFRP strips. 

CFD Application for Performance Based Safety Verification of Reinforced Concrete Beam in Computer Simulation Building Fire

2012 ◽  
Vol 601 ◽  
pp. 190-195
Author(s):  
Chia Chun Yu ◽  
Shih Cheng Wang ◽  
Cherng Shing Lin ◽  
Te Chi Chen
Keyword(s):  
Reinforced Concrete ◽  
Fire Protection ◽  
Fluid Dynamic ◽  
Bending Moment ◽  
Fire Intensity ◽  
Fire Damage ◽  
Rc Beams ◽  
Fire Dynamics ◽  
Rc Structures ◽  
Building Fire

More than 90% of the buildings in Taiwan use reinforced concrete (RC) structures. Before or after fire damage, whether the RC structure accord Performance Based Design (PBD) fire code or safe evaluation are important in building fire protection verification. However, obtaining fire thermal parameters detailed quantitative data from building fire tests or actual building fires are difficult. Therefore, computational fluid dynamic (CFD) integration to simulate fire scenarios has been widely utilized in fire protection engineering. This study utilizes Fire Dynamics Simulator (FDS) fire model and PHOENICS field model software to simulate fire development and beams inner temperature variation. The structural strength estimated using beam cross-sections temperature to investigate dynamic ultimate bending moment (Mu) of RC beams. This integration method can investigate the influence of different beam positions, fire intensity, fire duration and fire damage sustained (two or three faces heated) for RC beams fire protection safe verification.

scholarly journals Flexural Strengthening and Rehabilitation of Reinforced Concrete Beam Using BFRP Composites: Finite Element Approach

2019 ◽  
Vol 2019 ◽  
pp. 1-17 ◽  
Author(s):  
Asaad M. H. Kadhim ◽  
Hesham A. Numan ◽  
Mustafa Özakça
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Numerical Analysis ◽  
Mechanical Performance ◽  
Basalt Fiber ◽  
Reinforced Concrete Beam ◽  
Extensive Study ◽  
Rc Beams ◽  
Flexural Strengthening ◽  
Element Approach

Basalt fiber-reinforced polymer (BFRP) is adopted widely in recent years in many countries to rehabilitate or strengthen structural elements such as reinforced concrete (RC) beams because it is cheap and it has stellar mechanical performance. By activating the finite element (FE) simulation, the present research submits an extensive study on the strengthening and rehabilitation of damaged full-scale RC beams due to corrosions in the main reinforcement caused by BFRP sheets. Different parameters were taken into consideration such as corrosion grade, BFRP wrapping schemes, and the number of layers. The flexural performance of the models that build up as the control model and the damaged and the repaired methodologies by BFRP that are adopted and tested by others under the effects of four-point static loadings were also underwent examination. The full interaction at BFRP-concrete interface and the full bonding between sheets presupposed were investigated for all models. The numerical analysis findings were compared with the experimental measurements and found to be in good agreement. The current numerical analysis proved that the ultimate load rised by 14.8% in spite of 20% corrosion in the flexural steel rebar under eight layers of BFRP composite and bottom wrapping mode. In addition, under all strategies of wrapping schemes, the findings also indicated that the deflection ductility index noticeably reduced for RC beams with BFRP composites compared to the control beam. Finally, all the results of midspan deflection, crack patterns, and strain response of the composite system were analysed and discussed briefly.

Member and structural fragility of reinforced concrete structure under fire

2020 ◽  
Vol 11 (4) ◽  
pp. 409-435 ◽  
Author(s):  
Ranjit Kumar Chaudhary ◽  
Tathagata Roy ◽  
Vasant Matsagar
Keyword(s):  
Reinforced Concrete ◽  
Fire Resistance ◽  
Vulnerability Assessment ◽  
Fire Hazard ◽  
Fe Analysis ◽  
Content Type ◽  
Rc Structures ◽  
Structural Fire ◽  
Structural Fragility ◽  
Safety And Reliability

Purpose Despite recognizing the significance of risk-based frameworks in fire safety engineering, the usual approach in structural fire design is largely member/component level, wherein effect of uncertainties influencing the fire resistance of structures are not explicitly considered. In this context, a probabilistic framework is presented to investigate the vulnerability of a reinforced concrete (RC) members and structure under fire loading scenario. Design/methodology/approach The RC structures exposed to fire are modeled in a finite element (FE) platform incorporating material and geometric nonlinearity, in which the transient thermo-mechanical analysis is carried out by suitably incorporating the temperature variation of thermal and mechanical properties of both concrete and steel rebar. The stochasticity in the system is considered in structural resistance, thermal and fire model parameters, and the subsequent fragility curves are developed considering threshold limit state of deflection. Findings The fire resistance of RC structure is reported to be significantly lower in comparison to the RC members, thereby illustrating the current prescriptive design approaches based on studies of structural member behavior to be crucial from a safety and reliability point of view. Practical implications The framework developed for the vulnerability assessment of RC structures under fire hazard through FE analysis can be effectively used to estimate the structural fire resistance for other similar structure to enhance safety and reliability of structures under such extreme threats. Originality/value The paper proposes a novel methodology for vulnerability assessment of three-dimensional RC structures under fire hazard through FE analysis and provides comparison of the structural fragility with fragility developed for structural members. Moreover, the research emphasizes to assume 3D behavior of the structure rather than the approximate 2D behavior.

scholarly journals A Comparative Study of the Performance of Slender Reinforced Concrete Columns with Different Cross-Sectional Shapes

Fibers ◽  
2020 ◽  
Vol 8 (6) ◽  
pp. 35
Author(s):  
Safaa Qays Abdualrahman ◽  
Alaa Hussein Al-Zuhairi
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Slenderness Ratio ◽  
Structural Performance ◽  
Element Analysis ◽  
Cross Sectional ◽  
Rc Structures ◽  
Section Size ◽  
Concentric Loading ◽  
Rectangular Columns

Most reinforced concrete (RC) structures are constructed with square/rectangular columns. The cross-section size of these types of columns is much larger than the thickness of their partitions. Therefore, parts of these columns are protruded out of the partitions. The emergence of columns edges out of the walls has some disadvantages. This limitation is difficult to be overcome with square or rectangular columns. To solve this problem, new types of RC columns called specially shaped reinforced concrete (SSRC) columns have been used as hidden columns. Besides, the use of SSRC columns provides many structural and architectural advantages as compared with rectangular columns. Therefore, this study was conducted to explain the structural performance of slender SSRC columns experimentally and numerically via nonlinear finite element analysis. The study is based on nine RC specimens tested up to failure, as well as eighteen finite element (FE) models analyzed by Abaqus soft wear program. The use of SSRC columns led to increase strength by about 12% and reduce deformations, especially with slenderness ratio more than 40 as compared with equivalent square-shaped columns. Two design formulas were proposed to determine the compressive strength of SSRC columns under concentric loading. The results obtained indicate a good structural performance of SSRC columns when compared with equivalent square-shaped columns.

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