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

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.

Author(s):  
Tsuyoshi Kouta ◽  
Christian Bucher

<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>


2013 ◽  
Vol 838-841 ◽  
pp. 648-652
Author(s):  
Jian Long Cao ◽  
Hai Tao Long ◽  
Wen Luo

Using the finite element analysis software ABAQUS, the section temperature field of reinforced concrete columns under fire was analyzed. On this basis, the influence of the section size, the number of heated surface and the time of fire on the surface temperature were analyzed. Calculations indicate that the impact of the section size on temperature field cannot be considered when one surface was heated, three or surrounded by fire-sectional dimensions the influence was time-related. When the cross-sectional size reaches a certain value, the number of exposed surface on the temperature field can be neglected. Sectional temperature increased by time and the temperature rise rate is high at start then slow down close by fire surface, however, the rate is more stable all the time at internal surface.


Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1578
Author(s):  
Sławomir Dudziak

The paper concerns the non-linear finite element analysis (NLFEA) of Reinforced Concrete (RC) structures for engineering applications. The required level of complexity of constitutive models for such analysis was discussed and non-linear elastic models combined with the smeared cracking approach proved to be efficient. A new constitutive hypoelastic-brittle model of concrete based on these assumptions was proposed. Moreover, a method including the tension stiffening effect (TS) was developed. This phenomenon is connected with the bond properties between concrete and steel and, in some situations, has significant influence on the deflections of RC structures. It is often neglected by or included in the constitutive model of concrete. In the paper, an alternative approach was presented, in which this phenomenon is taken into account by generalising the material model of reinforcing steel. This approach is consistent with modern design standards and has solid physical foundations. The proposed models were implemented in the Abaqus code via UMAT user’s procedure coded in FORTRAN. Model verification and validation were presented in four case studies, concerning: a Willam’s test (examination on material point level), a beam with bending failure, and two beams with shear failure (with and without stirrups). The obtained results were compared with experimental outcomes and numerical results obtained by other researchers. The presented approach enables the accurate prediction not only of load capacity but of structural deformability, due to the precise description of TS. Thus, it promises to be a useful engineering tool.


2011 ◽  
Vol 2011 ◽  
pp. 1-14 ◽  
Author(s):  
Tanarat Potisuk ◽  
Christopher C. Higgins ◽  
Thomas H. Miller ◽  
Solomon C. Yim

Finite element (FE) modeling techniques were developed to isolate the different contributions of corrosion damage to structural response of experimental reinforced concrete beams with shear-dominated behavior. Corrosion-damage parameters included concrete cover spalling due to the expansion of corrosion products; uniform stirrup cross-sectional loss from corrosion; localized stirrup cross-sectional loss due to pitting; debonding of corrosion-damaged stirrups from the concrete. FE analyses were performed including both individual and combined damages. The FE results matched experimental results well and quantitatively estimated capacity reduction of the experimental specimens.


2021 ◽  
Vol 11 (13) ◽  
pp. 6094
Author(s):  
Hubdar Hussain ◽  
Xiangyu Gao ◽  
Anqi Shi

In this study, detailed finite element analysis was conducted to examine the seismic performance of square and circular hollow steel braces under axial cyclic loading. Finite element models of braces were constructed using ABAQUS finite element analysis (FEA) software and validated with experimental results from previous papers to expand the specimen’s matrix. The influences of cross-section shape, slenderness ratio, and width/diameter-to-thickness ratio on hysteretic behavior and compressive-tensile strength degradation were studied. Simulation results of parametric studies show that both square and circular hollow braces have a better cyclic performance with smaller slenderness and width/diameter-to-thickness ratios, and their compressive-tensile resistances ratio significantly decreases from cycle to cycle after the occurrence of the global buckling of braces.


Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 506 ◽  
Author(s):  
Alexandre Mathern ◽  
Jincheng Yang

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.


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