Carbon fiber reinforced polymer strengthened reinforced concrete square columns under pre-existing eccentric loads

2021 ◽  
pp. 136943322110297
Author(s):  
Nima Kian ◽  
Masood Farzam ◽  
Mohammad Rezaie Oshtolagh
Keyword(s):  
Experimental Studies ◽  
Load Condition ◽  
Fiber Reinforced Polymer ◽  
Element Analysis ◽  
Good Efficiency ◽  
Interaction Diagram ◽  
Confinement Pressure ◽  
Reinforced Polymer ◽  
Good Agreement ◽  
Strengthening Method

Numerous experimental studies have been conducted on the behavior of strengthened columns, mostly with glued layers of FRP before load application, and rarely under the pre-existing load. Results confirm a good efficiency of strengthening in the compression-controlled region of the columns, as mentioned in design codes and guides such as ACI 440.2R-17. However, their behavior in the tension-controlled region is still a challenging subject. Moreover, when the eccentricity is large enough, the efficiency of the strengthening method needs more attention. This study aimed at strengthening six RC columns in the tension-controlled region under the pre-existing load condition. Furthermore, tested specimens were verified using a nonlinear finite element analysis performed in ATENA software. Moreover, some identical strengthened specimens, which were not subjected to pre-existing load during strengthening, were modeled to capture the effect of pre-existing loads. The results of the analyses were in good agreement with experimental data. Comparison of numerical results obtained for columns strengthened without pre-existing load, and under pre-existing load showed that pre-existing loading significantly reduced the efficiency of FRP jacketing. Also, assuming a linear variation of confinement pressure in the tension-controlled region of the interaction diagram results in good agreement with attained results.

scholarly journals Experimental Study on Strengthening of RC Short Columns with BFRP Sheets

2018 ◽  
Vol 7 (3.12) ◽  
pp. 48
Author(s):  
Arathi Krishna ◽  
Milu Mary Jacob ◽  
K Saravana Raja Mohan
Keyword(s):  
Experimental Studies ◽  
Basalt Fiber ◽  
Load Condition ◽  
Primary Objective ◽  
Fiber Reinforced Polymer ◽  
Analytical Models ◽  
Fiber Reinforced ◽  
Short Columns ◽  
Reinforced Polymer ◽  
Materials Used

Earlier the methods adopted for the repair and rehabilitation were the external bonding of the damaged component with steel fibers and steel jackets. But the major problem that caused due to this steel components is corrosion. Fiber Reinforced Polymer (FRP) composite materials used for strengthening of components in the form of confinement is of considerable importance in civil engineering. This paper presents the results of axially loaded RC short columns which are strengthened by providing confinement with new material BFRP. The primary objective of this work is to examine the load carrying capacity of concrete columns confined with basalt fiber reinforced polymer jacket (BFRP) which is considered as an abstruse material for strengthening. BFRP materials are non-corrosive, non-magnetic, and chemical resistant and they are progressively being used for repair, rehabilitation, and strengthening of structures that are not stable enough to carry loads. The parameters considered in the study are full and partial wrapping and the number of layers of confinement. The results obtained from the experimental studies and the analytical models precisely shows that the BFRP confinements will upgrade the compressive strength of columns under the given load condition.

Study on the stiffness degradation in concrete continuous beam with externally prestressed CFRP tendons under fatigue loading

2021 ◽  
pp. 136943322199249
Author(s):  
Xing Li ◽  
Jiwen Zhang ◽  
Jun Cheng
Keyword(s):  
Fatigue Life ◽  
Fatigue Loading ◽  
Load Level ◽  
Fiber Reinforced Polymer ◽  
Stiffness Degradation ◽  
Test Results ◽  
Reinforced Polymer ◽  
Continuous Beams ◽  
Practical Engineering ◽  
Good Agreement

This paper presents fatigue behaviors and the stiffness degradation law of concrete continuous beams with external prestressed carbon fiber-reinforced polymer (CFRP) tendons. Three specimens were tested under fatigue loading, and the influence of different load levels on the stiffness degradation and fatigue life were studied, and it was found that the stiffness degradation of three test specimens exhibited a three-stage change rule, namely rapid decrease, stable degradation, and sharp decline, but there are obvious differences in the rate and amplitude of stiffness degradation. The load level has a significant influence on the fatigue life of the test specimens. An analytical model with load level considered was proposed to calculate the residual stiffness and predict the stiffness degradation, which is in good agreement with the test results. The model of stiffness degradation presents a possible solution for practical engineering applications of concrete continuous beams with externally prestressed CFRP tendons subjected to different fatigue loadings.

Nonlinear Analysis of R.C Beams Strengthened with CFRP

2012 ◽  
Vol 166-169 ◽  
pp. 1517-1520
Author(s):  
Wen Sheng Li ◽  
Kai Wang
Keyword(s):  
Finite Element ◽  
Carbon Fiber ◽  
Nonlinear Analysis ◽  
Element Model ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Element Analysis ◽  
Flexural Performance ◽  
Reinforced Polymer ◽  
Flexural Resistance

In order to study on the flexural performances of beams strengthened with external bonded carbon fiber reinforced polymer（CFRP）sheets, nonlinear analysis is carried out by using software ANSYS. The results show that a reasonable finite element model, using a reasonable solution strategy can be a good simulation of CFRP flexural performance of reinforced concrete beams, and finite element analysis results with the experimental results have good consistency .The beams reinforced by carbon fiber polymer，the capacity of flexural resistance increased with the numbers of carbon fiber paste sheets, reinforced components of flexural capacity significantly improved, but the extent of its increase is not proportional with the numbers of carbon fiber paste sheets.

scholarly journals Conceptual Design of Composite Sandwich Structure Submarine Radome

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 1966 ◽  
Author(s):  
Waqas ◽  
Shi ◽  
Imran ◽  
Khan ◽  
Tong ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Composite Materials ◽  
Conceptual Design ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Element Analysis ◽  
The Core ◽  
Reinforced Polymer ◽  
Sandwich Core

Radomes are usually constructed from sandwich structures made of materials which usually have a low dielectric constant so that they do not interfere with electromagnetic waves. Performance of the antenna is increased by the appropriate assortment of materials enabling it to survive under marine applications, and it depends on composite strength-to-weight ratio, stiffness, and resistance to corrosion. The design of a sandwich core submarine radome greatly depends on the material system, number of layers, orientation angles, and thickness of the core material. In this paper, a conceptual design study for a sandwich core submarine radome is carried out with the help of finite element analysis (FEA) using two unidirectional composite materials—glass fiber reinforced polymer (GFRP) and carbon fiber reinforced polymer (CFRP)—as a skin material and six different core materials. Conceptual designs are obtained based on constraints on the composite materials’ failure, buckling, and strength. The thickness of the core is reduced under constraints on material and buckling strength. Finite element analysis software ANSYS WORKBENCH is used to carry out all the simulations.

scholarly journals Parametric Study on the Effect of Steel Confinement in Short Bridge Piers Retrofitted with Externally-Wrapped FRP

2019 ◽  
Vol 271 ◽  
pp. 01012
Author(s):  
Diogo Zignago ◽  
Michele Barbato
Keyword(s):  
Compressive Strength ◽  
Parametric Study ◽  
Fiber Reinforced Polymer ◽  
Confined Concrete ◽  
Bridge Piers ◽  
Element Analysis ◽  
Reinforced Polymer ◽  
Externally Bonded ◽  
Frp Wrapping ◽  
Concrete Model

Confinement of reinforced concrete (RC) piers generally has a beneficial effect on both the compressive strength and the ductility of the confined member. Thus, externally-bonded fiber-reinforced polymer (FRP) wrapping is often used as a retrofit technique for bridge piers when additional compressive strength is needed. This study employs finite element analysis and a recently developed FRP-and-steel confined concrete model to investigate the influence of internal steel confinement on the response of circular RC columns confined with FRP and subject to concentric axial load. This new model leads to more accurate estimates of the response of these columns, what is particularly relevant for piers in short span bridges that are subjected mainly to vertical loads, for which it could lead to a more efficient and economical piers’ retrofit, as well as a more accurate and less conservative bridge rating. A parametric study is conducted to examine the importance of some key parameters in the design of such columns.

Deflection Prediction of FRP-Strengthened Reinforced Concrete Beams

2011 ◽  
Vol 243-249 ◽  
pp. 621-624
Author(s):  
Gui Bing Li ◽  
Yu Gang Guo
Keyword(s):  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Rc Beams ◽  
Test Results ◽  
Structural Members ◽  
Modified Model ◽  
Reinforced Polymer ◽  
Service Load ◽  
Good Agreement

Bonding fiber reinforced polymer (FRP) laminates to the tension face of RC members has been proven to be an effective method to improve the flexural strength. However, structural members are not only needed to have adequate strength, but also to have adequate performance of deformation at service load levels. To evaluate the deflection of externally FRP-strengthened RC beams, a total of 18 RC beams, including 16 beams strengthened with CFRP laminate under different preload levels and 2 control beams, were tested. Based on the assumption that the section of the beam behaves a tri-linear moment-curvature response characterized by pre-crack stage, post-crack stage and failure stage and the test results, this paper presents a modified model to evaluate the deflection of CFRP-strengthened RC beams. The present modified model was verified by the similar test results, and shows a good agreement with the test results.

Experimental Studies on High Strength Concrete Beams Reinforced with Steel and GFRP Rebars

2012 ◽  
Vol 238 ◽  
pp. 669-673 ◽  
Author(s):  
Ying Hao Liu ◽  
Yong Yuan
Keyword(s):  
High Strength Concrete ◽  
Experimental Studies ◽  
High Strength ◽  
Fiber Reinforced Polymer ◽  
Structural Behavior ◽  
Strength Concrete ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Steel Rebars ◽  
Gfrp Rebars

The paper analyzes the structural behavior of high strength concrete (HSC) beams reinforced with hybrid glass fiber reinforced polymer (GFRP) and steel reinforcements. The analysis refers to HSC beams reinforced with GFRP rebars and steel rebars placed in different layers. Results of the experimental and theoretical investigation are represented and discussed. Significant features of the structural behavior regarding flexural strength, deflection, are pointed out.

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