scholarly journals Numerical modeling of circular, square and rectangular concrete columns wrapped with FRP under concentric and eccentric load

2019 ◽  
Vol 12 (3) ◽  
pp. 518-550
Author(s):  
D. S. OLIVEIRA ◽  
R. CARRAZEDO
Keyword(s):  
Numerical Modeling ◽  
Cross Sections ◽  
Axial Strain ◽  
Concrete Columns ◽  
Confined Concrete ◽  
Transverse Strain ◽  
The Finite Element Method ◽  
Eccentric Load ◽  
Compressive Stresses ◽  
Rectangular Columns

Abstract In this paper, the finite element method was used for the numerical modeling of columns with square, rectangular and circular cross sections wrapped with FRP. The numerical modeling was successfully calibrated with the experimental data considering axial load, axial strain and transverse strain. The distribution of compressive stresses in the cross section of the column indicates that for centered load, circular cross sections have uniform distribution and for square and rectangular sections the effective confined concrete was defined by parabolas and concentrates next to the rounded corners. For eccentric load, the effective confined region moves to the most confined edge, thus, this does not reduce the gain for square and rectangular columns, but is unfavorable for circular columns.

Influence of FRP-to-Concrete Gap Effect on Axial Strains of FRP-Confined Concrete Columns

2015 ◽  
Vol 1119 ◽  
pp. 760-765
Author(s):  
Thomas Vincent ◽  
Togay Ozbakkloglu
Keyword(s):  
Cross Sections ◽  
Axial Stress ◽  
Axial Strain ◽  
Strain Curve ◽  
Shrinkage Strain ◽  
Confined Concrete ◽  
Gap Effect ◽  
Stress Strain ◽  
Concrete Shrinkage ◽  
Concrete Interface

This paper reports on an experimental investigation on the influence of FRP-to-concrete interface gap, caused by concrete shrinkage, on axial compressive behavior of concrete-filled FRP tube (CFFT) columns. A total of 12 aramid FRP (AFRP)-confined concrete specimens with circular cross-sections were manufactured. 3 of these specimens were instrumented to monitor long term shrinkage strain development and the remaining 9 were tested under monotonic axial compression. The influence of concrete shrinkage was examined by applying a gap of up to 0.06 mm thickness at the FRP-to-concrete interface, simulating 800 microstrain of shrinkage in the radial direction. Axial strain recordings were compared on specimens instrumented with two different measurement methods: full-and mid-height linear variable displacement transformers (LVDTs). Results of the experimental study indicate that the influence of interface gap on stress-strain behavior is significant, with an increase in interface gap resulting in a decrease and increase in the compressive strength and ultimate axial strain, respectively. It was also observed that an increase in interface gap leads to a slight loss in axial stress at the transition region of the stress-strain curve. Finally, it is found that an increase in the interface gap results in a significant decrease in the ratio of the ultimate axial strains obtained from mid-section and full-height LVDTs.

Analysis of Unreinforced Ceramic Wall Panels in the Mounting State

2016 ◽  
Vol 861 ◽  
pp. 48-55
Author(s):  
Štěpán Karlík ◽  
Miloš Lavický ◽  
Jan Pěnčík
Keyword(s):  
Cross Sections ◽  
Building Materials ◽  
Experimental Tests ◽  
The Finite Element Method ◽  
The Czech Republic ◽  
Healthy Environment ◽  
Compressive Stresses ◽  
Wall Panels ◽  
Materials Used ◽  
Masonry Units

Properties of building materials used for the construction of surrounding structures significantly contribute to creating a healthy and comfortable microclimate inside the rooms. Ceramics belong among materials which exhibit very suitable properties for the formation of the healthy environment. It is also one of the reasons that the fired clay structures remain popular among builders and that recovery of ceramic prefabrication can be seen in the Czech Republic. The important step towards rediscovering the benefits of the prefabricated ceramic elements is forthcoming production of unreinforced ceramic wall panels made of fired clay masonry units with tongue and groove, connected in the bed joints by two-component adhesives. Conventional analytical model for vertical loads is used in the operating state. However, in the transport and mounting state it is a structure stressed by bending in its own plane. This paper is focused on the issue of load-bearing capacity of structures with masonry units cross-sections that are not filled in head joints and therefore are unable to transfer either tensile or compressive stresses. On the segment of the wall panel is performed numerical model analysis using the finite element method in the computing program ANSYS and comparison of this analysis results with the results of the experimental tests.

scholarly journals Axial Compressive Stress-Strain Model Developed for FRP-Confined Concrete Columns with Elliptical Cross Sections

2018 ◽  
Vol 2 (4) ◽  
pp. 67 ◽  
Author(s):  
Haytham Isleem ◽  
Zhenyu Wang
Keyword(s):  
Aspect Ratio ◽  
Cross Sections ◽  
Concrete Columns ◽  
Threshold Value ◽  
Confined Concrete ◽  
Elliptical Cross ◽  
Proposed Model ◽  
Axial Compressive Stress ◽  
Frp Confinement ◽  
Strain Model

Most existing studies conducted on fiber-reinforced polymer (FRP)-confined concrete have considered circular and square concrete columns, while limited studies have considered columns with rectangular sections. Studies have confirmed that the circular cross-sections exhibited higher confinement effectiveness, whereas in the case of non-circular cross-sections the efficiency of FRP confinement decreases with an increase of the sectional aspect ratio and there is no significant increase, particularly for columns with the aspect ratio of 2.0. As recently suggested by researchers, to significantly increase the effectiveness of FRP-confinement for these columns involves changing a rectangular section into an elliptical or oval section. According to the literature, most of the existing confinement models for FRP-confined concrete under axial compression have been proposed for columns with circular and rectangular cross-sections. However, modeling of the axial strength and strain of concrete confined with FRP in elliptical cross-sections under compression is limited. Therefore, this paper provides new expressions based on limited experimental data available in the literature. For a sufficient amount of FRP-confinement, the threshold value was proposed to be 0.02. Finally, the accuracy of the proposed model was verified by comparing its predictions with the same test database, together with those from the existing models.

scholarly journals Axial Compression Model for FRP Confined Concrete in Elliptical Cross Sections

2018 ◽  
Author(s):  
Zhenyu Wang ◽  
Haytham F. Isleem
Keyword(s):  
Aspect Ratio ◽  
Axial Compression ◽  
Cross Sections ◽  
Concrete Columns ◽  
Threshold Value ◽  
Confined Concrete ◽  
Elliptical Cross ◽  
Proposed Model ◽  
Frp Confinement ◽  
Test Database

Most of the existing studies conducted on FRP-confined concrete considered circular and square concrete columns, while limited studies were on columns with rectangular sections. The studies have confirmed that the circular cross-sections exhibited higher confinement effectiveness, whereas in the case of non-circular cross-sections the efficiency of FRP confinement decreases with an increase of the sectional aspect ratio and there is no significant increase, particularly for columns with the aspect ratio of 2.0. As recently suggested by the researchers, to significantly increase the effectiveness of FRP-confinement for these columns is by modifying a rectangular section to an elliptical or oval section. According to the literature, most of the existing confinement models for FRP-confined concrete under axial compression have been proposed for columns with circular and rectangular cross-sections. However, modeling the axial strength and strain of concrete confined with FRP in elliptical cross-sections under compression is most limited. Therefore, this paper provides new expressions based on limited experimental data available in the literature. For a sufficient amount of FRP-confinement, the threshold value was proposed to be 0.02. Finally, the accuracy of the proposed model was verified by comparing its predictions with the same test database, together with those from the existing models.

Statistical Comparison of the Results of Applying Several Methods in Checking Concrete Columns’ Fire Resistance

2016 ◽  
Vol 711 ◽  
pp. 572-579
Author(s):  
Maria Alzira Barros Ramalho ◽  
Miguel Chichorro Gonçalves
Keyword(s):  
Cross Sections ◽  
Fire Resistance ◽  
Room Temperature ◽  
Concrete Columns ◽  
Alternative Methodology ◽  
The Stability ◽  
The One ◽  
Comparison Of The Results ◽  
In Fire ◽  
Rectangular Columns

The main objective of this study is to help the structural designers so they can, quickly and efficiently, study the concrete columns’ fire resistance. The most expeditious methods of fire resistance verification in terms of ease of application by structural designers, the methods given in EN 1992-1-2 [1] in the form of tables (Method A, Method B and Method C), were used in the fire resistance verification of 12243 rectangular columns inserted in the stability projects of 63 buildings, carefully selected in order to be representative of the ones licensed in Portugal [2]. Noting that these methods lead to excessively conservative results, the authors developed an alternative methodology, also with expedite application, but leading to substantially less conservative results (although designed on the safety side). This methodology consists on the consultation of adimensional interaction diagrams in fire situation, Nfi/Mfi, developed using the 500oC Isotherm Method. In the development of these diagrams unexpected results were obtained in some columns’ cross-sections, for which the resistance at room temperature was lower than the one corresponding to a fire situation at level R60. Some of the factors that can contribute to the occurrence of these results are pointed out.

Compressive behavior of concrete-filled steel tubular columns with internal high-strength steel spiral confinement

2020 ◽  
pp. 136943322098165
Author(s):  
J.G. Teng ◽  
J.J. Wang ◽  
Guan Lin ◽  
J. Zhang ◽  
P. Feng
Keyword(s):  
Axial Compression ◽  
High Strength Steel ◽  
Axial Load ◽  
Axial Strain ◽  
High Strength ◽  
Concrete Columns ◽  
Steel Tube ◽  
Confined Concrete ◽  
Experimental Program ◽  
Cfst Columns

Concrete-filled steel tubular (CFST) columns have been extensively studied and widely used in practice. Existing research has shown that non-circular CFST columns is much less ductile than their circular counterparts, particularly when thin/high strength steel (HSS) tubes and high-strength concrete are used. To address this problem, a new form of CFST columns has recently been proposed by the first author. The new column consists of a steel tube filled with concrete that is confined with HSS spiral reinforcement typically with a yield stress exceeding 1000 MPa. These columns, referred to as confined concrete-filled steel tubular (CCFST) columns, also maintain the ease for connection to CFST or steel beams. This paper presents the results of a series of concentric axial compression tests on such columns of square cross-section to demonstrate their advantages. The experimental program included 13 CCFST columns, four CFST columns without internal spiral confinement, two hollow steel tube (HST) columns, and 11 circular HSS spiral-confined concrete columns. Three different compressive strengths and three HSS spiral pitches were examined in the experimental program. The CFST columns, HST columns, and HSS spiral-confined concrete columns were all tested under axial compression to gain a good understanding of the confinement mechanism in a CCFST column. The test results show that the new columns possess much greater ductility than those without internal spiral confinement, although the use of HSS spirals increases the steel volume by only a small percentage. It is also shown that the axial load-axial strain curve of a CCFST column can be conservatively predicted by summing the axial load-axial strain curves of the hollow steel tube without local buckling, the HSS spiral-confined concrete core, and the sandwiched concrete between the two.

scholarly journals Axial Compression Model for FRP Confined Concrete in Elliptical Cross Sections

2018 ◽  
Author(s):  
Haytham F. A. Isleem
Keyword(s):  
Aspect Ratio ◽  
Axial Compression ◽  
Cross Sections ◽  
Concrete Columns ◽  
Threshold Value ◽  
Confined Concrete ◽  
Elliptical Cross ◽  
Proposed Model ◽  
Frp Confinement ◽  
Test Database

Most of the existing studies conducted on FRP-confined concrete considered circular and square concrete columns, while limited studies were on columns with rectangular sections. The studies have confirmed that the circular cross-sections exhibited higher confinement effectiveness, whereas in the case of non-circular cross-sections the efficiency of FRP confinement decreases with an increase of the sectional aspect ratio and there is no significant increase, particularly for columns with the aspect ratio of 2.0. As recently suggested by the researchers, to significantly increase the effectiveness of FRP-confinement for these columns is by modifying a rectangular section to an elliptical or oval section. According to the literature, most of the existing confinement models for FRP-confined concrete under axial compression have been proposed for columns with circular and rectangular cross-sections. However, modeling the axial strength and strain of concrete confined with FRP in elliptical cross-sections under compression is most limited. Therefore, this paper provides new expressions based on limited experimental data available in the literature. For a sufficient amount of FRP-confinement, the threshold value was proposed to be 0.02. Finally, the accuracy of the proposed model was verified by comparing its predictions with the same test database, together with those from the existing models.

scholarly journals Axial Compression Model for FRP Confined Concrete in Elliptical Cross Sections

2018 ◽  
Author(s):  
Zhenyu Wang ◽  
Haytham F. Isleem
Keyword(s):  
Aspect Ratio ◽  
Axial Compression ◽  
Cross Sections ◽  
Concrete Columns ◽  
Threshold Value ◽  
Confined Concrete ◽  
Elliptical Cross ◽  
Proposed Model ◽  
Frp Confinement ◽  
Test Database

Most of the existing studies conducted on FRP-confined concrete considered circular and square concrete columns, while limited studies were on columns with rectangular sections. The studies have confirmed that the circular cross-sections exhibited higher confinement effectiveness, whereas in the case of non-circular cross-sections the efficiency of FRP confinement decreases with an increase of the sectional aspect ratio and there is no significant increase, particularly for columns with the aspect ratio of 2.0. As recently suggested by the researchers, to significantly increase the effectiveness of FRP-confinement for these columns is by modifying a rectangular section to an elliptical or oval section. According to the literature, most of the existing confinement models for FRP-confined concrete under axial compression have been proposed for columns with circular and rectangular cross-sections. However, modeling the axial strength and strain of concrete confined with FRP in elliptical cross-sections under compression is most limited. Therefore, this paper provides new expressions based on limited experimental data available in the literature. For a sufficient amount of FRP-confinement, the threshold value was proposed to be 0.02. Finally, the accuracy of the proposed model was verified by comparing its predictions with the same test database, together with those from the existing models.

scholarly journals Special Issue “Applications of Finite Element Modeling for Mechanical and Mechatronic Systems”

2021 ◽  
Vol 11 (11) ◽  
pp. 5170
Author(s):  
Marek Krawczuk ◽  
Magdalena Palacz
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Modeling ◽  
Engineering Practice ◽  
The Finite Element Method ◽  
Special Issue ◽  
Mechatronic Systems ◽  
Modeling And Analysis ◽  
Modern Engineering ◽  
Concise Description

Modern engineering practice requires advanced numerical modeling because, among other things, it reduces the costs associated with prototyping or predicting the occurrence of potentially dangerous situations during operation in certain defined conditions. Different methods have so far been used to implement the real structure into the numerical version. The most popular have been variations of the finite element method (FEM). The aim of this Special Issue has been to familiarize the reader with the latest applications of the FEM for the modeling and analysis of diverse mechanical problems. Authors are encouraged to provide a concise description of the specific application or a potential application of the Special Issue.

Sign in / Sign up

Export Citation Format

Share Document