scholarly journals Application of Drucker-Prager Plasticity Model for Stress-Strain Modeling of FRP Confined Concrete Columns

2011 ◽  
Vol 14 ◽  
pp. 687-694 ◽  
Author(s):  
Jiafei Jiang ◽  
Yufei Wu ◽  
Xuemei Zhao
Keyword(s):  
Concrete Columns ◽  
Confined Concrete ◽  
Plasticity Model ◽  
Stress Strain ◽  
Strain Modeling

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.

scholarly journals Damage plasticity model for passively confined concrete

2019 ◽  
Vol 275 ◽  
pp. 02016
Author(s):  
Ben-ben Li ◽  
Hai-bei Xiong ◽  
Jia-fei Jiang ◽  
Yang Zhan
Keyword(s):  
Yield Stress ◽  
Concrete Columns ◽  
Confined Concrete ◽  
Flow Rule ◽  
Good Prediction ◽  
Plasticity Model ◽  
Dilation Angle ◽  
Good Prediction Accuracy ◽  
Concrete Damage ◽  
Concrete Damage Plasticity

This paper presents a modified concrete damage plasticity model (CDPM) for passively confined concrete within the concrete damage plasticity theory frame in ABAQUS. The modified CDPM can be used to simulate concrete under non-uniform passive confinement, for example, Fiber-reinforced polymer (FRP)-confined square concrete columns. The modification of CDPM includes a flow rule and a strain hardening/softening criterion in which dilation angle and yield stress are important parameters. Based on the true-triaxial experiment results of passively confined concrete, the dilation angle and yield stress were determined considering different confinement stiffness and non-uniform confinement stiffness ratio. Finally, the modified CDPM were incorporated in the ABAQUS model. The prediction of the finite element model of FRP-confined square concrete columns shows good prediction accuracy.

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.

Experimental Study on Axially-Loaded Concrete Columns with Various Sizes Confined by CFRP

2013 ◽  
Vol 405-408 ◽  
pp. 706-709 ◽  
Author(s):  
Yue Ling Long ◽  
Jiang Zhu
Keyword(s):  
Experimental Study ◽  
Size Effects ◽  
Peak Stress ◽  
Plain Concrete ◽  
Concrete Columns ◽  
Experimental Results ◽  
Confined Concrete ◽  
Stress Strain ◽  
Axially Loaded ◽  
Strain Model

Eight concrete columns with various sizes confined by CFRP and four plain concrete columns as the control specimens were axially loaded to failure in order to investigate size effects in concrete columns confined by CFRP. Experimental results show that CFRP can increase considerably both the capacity and ductility of the concrete specimens. Furthermore, the peak stress of the unconfined concrete decreases with the size of the specimens increasing. Similarly, the peak stress of confined concrete decreases with the size of the specimens increasing when the lateral confining stresses are the same. Hence, the size effects should be considered in the stress-strain model of concrete confined by CFRP.

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.

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.

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