scholarly journals Low-Cost Fiber Rope Reinforced Polymer (FRRP) Confinement of Square Columns with Different Corner Radii

Buildings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 355
Author(s):  
Qudeer Hussain ◽  
Anat Ruangrassamee ◽  
Somnuk Tangtermsirikul ◽  
Panuwat Joyklad ◽  
Anil C. Wijeyewickrema
Keyword(s):  
Ultimate Strength ◽  
Predictive Models ◽  
Axial Stress ◽  
Low Cost ◽  
Concrete Columns ◽  
Confined Concrete ◽  
Test Results ◽  
Stress Strain ◽  
Reinforced Polymer

This research investigates the behavior of square concrete columns externally wrapped by low-cost and easily available fiber rope reinforced polymer (FRRP) composites. This study mainly aims to explore the axial stress-strain relationships of FRRP-confined square columns. Another objective is to assess suitable predictive models for the ultimate strength and strain of FRRP-confined square columns. A total of 60 square concrete columns were cast, strengthened, and tested under compression. The parameters were the corner radii of square columns (0, 13, and 26 mm) and different materials of FRRP composites (polyester, hemp, and cotton FRRP composites). The strength and deformability of FRRP-confined specimens were observed to be higher than the unconfined specimens. It was observed that strength gains of FRRP-confined concrete columns and corner radii were directly proportional. The accuracy of ultimate strength and strain models developed for synthetic FRRP-confined square columns was assessed using the test results of this study, showing the need for the development of improved predictive models for FRRP-confined square columns. Newly developed unified models were found to be accurate in predicting the ultimate strength and strain of FRRP-confined columns.

Design-oriented axial stress–strain model for partially fiber-reinforced-polymer-confined normal-strength concrete

2020 ◽  
Vol 23 (16) ◽  
pp. 3481-3495
Author(s):  
Junlong Yang ◽  
Jizhong Wang ◽  
Ziru Wang
Keyword(s):  
Axial Stress ◽  
Concrete Columns ◽  
Fiber Reinforced Polymer ◽  
Confined Concrete ◽  
Normal Strength Concrete ◽  
Stress Strain ◽  
New Model ◽  
Strength Concrete ◽  
Reinforced Polymer ◽  
Normal Strength

Due to the influence of “arching action” in fiber-reinforced polymer (FRP) partially confined concrete columns as a result of the unconfined regions, the confinement of the concrete columns wrapped with discrete FRP strips is less efficient when compared with full wrapping schemes. This study comprehensively investigates the difference of the the confinement mechanism between fully and partially FRP confined circular normal-strength concrete and thus presents a new design-oriented model to predict the stress–strain relationships of partially FRP confined normal-strength concrete. The formulas used to determine the strength and corresponding strain of several key points on the stress–strain curves are also proposed by the regression analysis according to a reliable test database from the relevant literature. Besides, another selected database including 100 FRP partially wrapped circular concrete columns is also collected for model verification. The results show that better performance can be achieved by the new model compared with the selected models in predicting the ultimate conditions of partially FRP confined concrete. Finally, some specimens are chosen to assess the performance of the new model in predicting the complete axial stress–strain curves. The comparisons reveal that satisfactory accuracy and good agreement can be achieved between the theoretical predictions and experimental observations.

scholarly journals Experimental Study on CFRP-Confined Circularized Concrete-Filled Square Steel Tube Short Columns

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Yuchuan Wen ◽  
Zhongjun Hu ◽  
Anningjing Li ◽  
Quanheng Li ◽  
Xuepeng Li ◽  
...  
Keyword(s):  
Concrete Strength ◽  
Concrete Columns ◽  
Steel Tube ◽  
Confined Concrete ◽  
Test Results ◽  
Stress Strain ◽  
Short Columns ◽  
Reinforced Polymer ◽  
Square Steel Tube ◽  
Strain Model

This study investigates the suitability of the circularization technique for strengthening square concrete-filled square steel tube (CFSST) short columns. A total of 16 specimens were tested under axial compression. The main parameters under investigation were concrete strength, the thickness of arc cement mortar layer components (CAM), and the layers of carbon fiber-reinforced polymer (CFRP) sheets. Test results indicated that the failure mode of CFRP-confined circularized CFSST (C-C-CFSST) columns was similar to that of CFRP-confined concrete columns. The CFRP-confined circularized strengthening method can increase confinement efficacy and reduce the stress concentration at the corners of CFSST columns. Three existing CFRP-confined concrete stress-strain models were evaluated using the test results. The predictions of the Lam and Teng stress-strain model agree well with the test data.

Behavior of Large-Scale Circular and Square RC Columns Confined with Carbon Fiber-Reinforced Polymer under Uniaxial Compression

2010 ◽  
Vol 163-167 ◽  
pp. 3686-3693
Author(s):  
Zhen Yu Wang ◽  
Dai Yu Wang ◽  
Da Gang Lu
Keyword(s):  
Carbon Fiber ◽  
Large Scale ◽  
Axial Stress ◽  
Concrete Columns ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Stress Strain ◽  
Rc Columns ◽  
Reinforced Polymer

Most experimental studies concerning the stress-strain behavior of concrete columns confined with carbon fiber-reinforced polymer (CFRP) focused on plain concrete columns with small section. In this study, 34 concrete columns with large-scale circular and square cross section confined with CFRP were tested under axial compression to investigate the influence of sectional dimensions, internal steel reinforcement and thickness of CFRP jackets on the stress-strain behaviors. Test results indicated that the confinement of CFRP resulted in significant increase in axial stress and strain for circular RC columns, while remarkable enhancement in axial strain but slightly in axial stress for square RC columns. The stress-strain responses of CFRP-confined square RC columns were significantly influenced by sectional dimensions and internal transverse reinforcement. The typical confinement ratio, which is obtained from studies on CFRP-confined unreinforced concrete columns with small cross sections, was not applicable for the case of large-scale square RC columns.

scholarly journals Experimental Investigation on Interfacial Defect Criticality of FRP-Confined Concrete Columns

Sensors ◽  
2019 ◽  
Vol 19 (3) ◽  
pp. 468 ◽  
Author(s):  
Renyuan Qin ◽  
Denvid Lau ◽  
Lik-ho Tam ◽  
Tiejun Liu ◽  
Dujian Zou ◽  
...  
Keyword(s):  
Concrete Columns ◽  
Confined Concrete ◽  
Original Design ◽  
Stress Strain ◽  
Strain Behavior ◽  
Interfacial Defect ◽  
Reinforced Polymer ◽  
Defect Area ◽  
Frp Confinement ◽  
Non Destructive

Defects between fiber reinforced polymer (FRP) and repaired concrete components may easily come out due to misoperation during manufacturing, environmental deterioration, or impact from external load during service life. The defects may cause a degraded structure performance and even the unexpected structural failure. Different non-destructive techniques (NDTs) and sensors have been developed to assess the defects in FRP bonded system. The information of linking up the detected defects by NDTs and repair schemes is needed by assessing the criticality of detected defects. In this study, FRP confined concrete columns with interfacial defects were experimentally tested to determine the interfacial defect criticality on structural performance. It is found that interfacial defect can reduce the FRP confinement effectiveness, and ultimate strength and its corresponding strain of column deteriorate significantly if the interfacial defect area is larger than 50% of total confinement area. Meanwhile, proposed analytical model considering the defect ratio is validated for the prediction of stress–strain behavior of FRP confined columns. The evaluation of defect criticality could be made by comparing predicted stress–strain behavior with the original design to determine corresponding maintenance strategies.

Compression Tests on Large-Scale Concrete-Filled GFRP Tubes

2011 ◽  
Vol 71-78 ◽  
pp. 1113-1117
Author(s):  
Pan Xie
Keyword(s):  
Large Scale ◽  
Concrete Columns ◽  
Fiber Reinforced Polymer ◽  
Confined Concrete ◽  
Test Results ◽  
Compression Tests ◽  
Reinforced Polymer ◽  
Strain Behaviour ◽  
Calculation Results ◽  
Polymer Tubes

To enable reliable prediction of the stress-strain behaviour of GFRP-confined concrete, the mechanical properties of GFRP tube needs to be properly understood and modelled. This paper presents test results of an experimental investigation carried out on 400-mm-diameter and 800-mm-height concrete-filled fiber reinforced polymer tubes. A total of four GFRP-confined concrete columns were subjected to concentric compression to identify the properties of GFRP tube. The performance of GFRP tubes in the tests were compared with the calculation results based on the classical lamination theory. In addition, more in-depth interpretations of the test results and further tests need to be refined in future tests to better capture the properties of the GFRP tube.

Behavior and modeling of post-heated circular concrete specimens repaired with fiber-reinforced polymer composites

2021 ◽  
pp. 136943322110585
Author(s):  
Seyed Mehrdad Elhamnike ◽  
Rasoul Abbaszadeh ◽  
Vahid Razavinasab ◽  
Hadi Ziaadiny
Keyword(s):  
Strain Curve ◽  
Concrete Columns ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Concrete Members ◽  
Frp Composites ◽  
Reinforced Polymer ◽  
Fiber Reinforced Polymer Composites

Exposure of buildings to fire is one of the unexpected events during the life of the structure. The heat from the fire can reduce the strength of structural members, and these damaged members need to be strengthened. Repair and strengthening of concrete members by fiber-reinforced polymer (FRP) composites has been one of the most popular methods in recent years and can be used in fire-damaged concrete members. In this paper, in order to provide further data and information about the behavior of post-heated circular concrete columns confined with FRP composites, 30 cylindrical concrete specimens were prepared and subjected under four exposure temperatures of 300, 500, 700, and 900. Then, specimens were repaired by carbon fiber reinforced polymer composites and tested under axial compression. Results indicate that heating causes the color change, cracks, and weight loss of concrete. Also, with the increase of heating temperature, the shape of stress–strain curve of FRP-retrofitted specimens will change. Therefore, the main parts of the stress–strain curve such as ultimate stress and strain and the elastic modulus will change. Thus, a new stress–strain model is proposed for post-heated circular concrete columns confined by FRP composites. Results indicate that the proposed model is in a good agreement with the experimental data.

Mechanical Properties of Large Scale Confined Concrete

2011 ◽  
Vol 94-96 ◽  
pp. 1983-1988
Author(s):  
Jia Song ◽  
Zhen Bao Li ◽  
Yong Ping Xie ◽  
Xiu Li Du ◽  
Yue Gao
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Axial Compression ◽  
Large Scale ◽  
Plain Concrete ◽  
Concrete Columns ◽  
Confined Concrete ◽  
Transverse Reinforcement ◽  
Test Results ◽  
Reinforcement Configuration

An experimental study was made of the mechanical properties of large scale confined concrete subjected to the axial compression test. Eleven tied concrete columns and six plain concrete prisms were tested. In the test, each specimen had the same transverse reinforcement configuration, and similar volumetric ratio of lateral steel, while different size. The test results in this paper indicate that the size of the specimen has no obvious relationship with the ultimate strength, however, it does affect the post-peak ductility to some extent. As a supplement to the experimental study, a finite element method was adopted to imitate the mechanical behavior of the confined concrete under axial compression. The results of the imitation in this paper indicate the confinement mechanism of large scale specimens.

Sign in / Sign up

Export Citation Format

Share Document