scholarly journals Compressive Behavior of Bamboo Sheet Twining Tube-Confined Concrete Columns

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4124
Author(s):  
Xunyu Cheng ◽  
Yang Wei ◽  
Yuhan Nie ◽  
Gaofei Wang ◽  
Guofen Li
Keyword(s):  
Concrete Strength ◽  
Concrete Columns ◽  
Confined Concrete ◽  
Test Results ◽  
Compressive Behavior ◽  
Concrete Core ◽  
Strain Relationship ◽  
Mode Stress ◽  
New Type ◽  
Good Agreement

This study experimentally investigated various axial compressive parameters of a new type of confined concrete, which is termed bamboo sheet twining tube-confined concrete (BSTCC). This new composite structure was composed of an outer bamboo composite tube (BCT) jacket and a concrete core. Under axial compression, the parameters of thirty-six specimens include concrete strength (i.e., C30 and C50) and BCT thickness (i.e., 6, 12, 18, 24, and 30 layers). The mechanical properties of the BSTCC specimens from the perspective of the failure mode, stress-strain relationship, effect of BCT thickness and dilation behavior were analyzed. The results showed that, in compression, with an increase in BCT thickness in the range of 18-layers of bamboo sheets, the strength increased remarkably. When the strength of the concrete core was high, the confinement effect of the BCT was reduced. In addition, the BCT thickness relieved the dilation of the BSTCC specimens. Finally, the experimental results were compared with predictions obtained from 7 existing FRP-confined concrete models. All the predictions had good agreement with the test results, which further confirmed that the models developed for FRP-confined concrete can provide an acceptable approximation of the ultimate strength of the BSTCC specimens.

Experimental Study on Compressive Behavior of CFRP Confined Concrete Columns

2012 ◽  
Vol 446-449 ◽  
pp. 3725-3729
Author(s):  
Wei Hua Ma ◽  
Hong Zhen Kang
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Concrete Strength ◽  
Concrete Columns ◽  
Confined Concrete ◽  
Concrete Column ◽  
Compressive Behavior ◽  
Reinforcing Effect ◽  
Research Results ◽  
Compressive Tests

Compressive tests of 30 concrete column specimens with three concrete strength grades are carried out in this paper to study ultimate compressive strength of specimens. The specimens are divided into three groups, that is, unconfined, confined by CFRP with no initial compression and confined by CFRP with various initial compressions. The different initial compressions’ influence on ultimate stresses and strains are investigated. The decrease of CFRP reinforcing effect due to pre-compression are analyzed. The research results provide experimental datum for reinforced design of existing concrete columns.

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.

scholarly journals Effects of Concrete Core Technological Defects on the Strength of Tube Confined Concrete Elements

2018 ◽  
Vol 7 (3.2) ◽  
pp. 376
Author(s):  
Oleksandr Semko ◽  
Olga Gukasian ◽  
Serhii Skliarenko
Keyword(s):  
Concrete Strength ◽  
Experimental Studies ◽  
Fracture Pattern ◽  
Confined Concrete ◽  
Concrete Core ◽  
Different Types ◽  
Technological Defects ◽  
Concrete Elements ◽  
Core Production ◽  
Physical And Mechanical Characteristics

The paper sums up a series of experimental studies describing the influence of most types of concreting common defects, such as core weakening: weak compression inclusions, voids, height heterogeneity of concrete. The basis of the experimental study is the research on the concrete core production conditions influence on tube confined concrete elements and the change in physical and mechanical characteristics of the elements. The concrete strength is estimated based on the results of the study of specially shaped samples with given dimensions. According to the results of concreting samples with different types of modeled defects (abnormalities) inspection, the most dangerous damages of the concrete core were identified and different variants of the height strength retrogression of the elements under study were analyzed. As a result, the degree and type of damage to the tube confined concrete elements core of the samples, which affect the fracture pattern, was established. 

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.

An Experiment on Bond-Anchoring Property of Prestressing Spiral Groove Tendon

2011 ◽  
Vol 105-107 ◽  
pp. 1685-1688
Author(s):  
Meng Chen ◽  
Pin Wu Guan
Keyword(s):  
Yield Strength ◽  
Failure Modes ◽  
Concrete Strength ◽  
Concrete Cover ◽  
Tensile Yield Strength ◽  
Test Results ◽  
Statistical Regression ◽  
Spiral Groove ◽  
Anchoring Strength ◽  
Good Agreement

Prestressing spiral groove tendon is a new sort prestressing tendon, its characteristic value of tensile yield strength fyk=1000MPa. Firstly, the yield strength, ultimate tensile strength, elastic modulus and elongation are all tested. According to 68 pullout tests, the bond-anchoring curves and failure modes have been studied, and the effects of concrete strength, diameter, anchoring length, thickness of concrete cover and stirrup ratio have been all analyzed. Finally, the equation for ultimate bond-anchoring strength has been suggested by statistical regression, and the test results are in good agreement with values of the suggested equation.

Strength model of FRP confined concrete columns based on analytical analysis and experimental test

2019 ◽  
Vol 11 (1) ◽  
pp. 82-106 ◽  
Author(s):  
Mahfoud Touhari ◽  
Ratiba Kettab Mitiche
Keyword(s):  
Concrete Strength ◽  
Compressive Force ◽  
Concrete Columns ◽  
Fiber Reinforced Concrete ◽  
Confined Concrete ◽  
Fiber Reinforced ◽  
Reinforced Concrete Column ◽  
Theoretical Assumption ◽  
Hoop Strain ◽  
Content Type

Purpose Covering a fiber-reinforced concrete column (fiber reinforced plastic (FRP)) improves the performance of the column primarily. The purpose of this paper is to investigate the behavior of small FRP concrete columns that are subject to axial pressure loading, in order to study the effect of many parameters on the effectiveness of FRP couplings on circular and square concrete columns. Design/methodology/approach These parameters include the shape of the browser (circular and square), whole core and cavity, square radius of square columns, concrete strength (low strength, normal and high), type of FRP (carbon and glass) and number of FRP (1–3) layers. The effective fibrillation failure strain was investigated and the effect of effective lateral occlusion pressure. Findings The results of the test showed that the FRP-coated columns improved significantly the final conditions of both the circular and square samples compared to the unrestricted columns; however, improvement of square samples was not as prominent as improvement in circular samples. The results indicated that many parameters significantly affected the behavior of FRP-confined columns. A new model for predicting compressive force and the corresponding strain of FRP is presented. A good relationship is obtained between the proposed equations and the current experimental results. Originality/value The average hoop strain in FRP wraps at rupture in FRP-confined concrete specimens can be much lower than that given by tensile coupon tests, meaning the theoretical assumption that the FRP-confined concrete cylinder ruptures when the FRP material tensile strength attained at its maximum is not suitable. Based on this observation, the effective peak strength and corresponding strain formula for FRP concrete confined columns must be based on the effective hoop rupture strain composite materials.

scholarly journals Uniaxial Compressive Behavior of Concrete Columns Confined with Superelastic Shape Memory Alloy Wires

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1227 ◽  
Author(s):  
Chenkai Hong ◽  
Hui Qian ◽  
Gangbing Song
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Seismic Design ◽  
Large Deformations ◽  
Axial Loading ◽  
Concrete Columns ◽  
Confined Concrete ◽  
Loading Capacity ◽  
Compressive Behavior ◽  
Concrete Cylinders

Superelastic shape memory alloy (SMA) exhibits the ability to undergo large deformations before reverting back to its undeformed shape following the removal of the load. This unique property underlies its great potential in the seismic design and retrofitting of structure members. In this paper, superelastic SMA wires were utilized to confine concrete cylinders to enhance their axial compressive behavior. The axial carrying and deformation capacities of SMA-confined concrete cylinders are assessed by uniaxial compression testing on a total of eight SMA-confined concrete columns and one unconfined column. The influence of the amount of SMA and the prestrain level of SMA wires, as well as the reinforcing mode, on the axial carrying and deformation capacity of confined concrete columns were considered. The analysis focuses on the axial carrying capacity and deformation performance of concrete columns reinforced with superelastic SMA under different loading conditions. Based on the experimental data and analysis results, it is found that superelastic SMA wires can increase the axial loading capacity and enhance deformation performance of concrete columns. Under the same loading condition, the ultimate bearing capacity of SMA-confined concrete columns increases as the increasing of the amount of SMA wire. The results of this study verify the effectiveness of superelastic SMA in enhancing the loading capacity and deformation behavior of concrete cylinders.

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.

Experimental Study on Mechanical Characteristics of CSG Materials

2011 ◽  
Vol 243-249 ◽  
pp. 2059-2064
Author(s):  
De Gao Zou ◽  
Dong Qing Li ◽  
Bin Xu ◽  
Xian Jing Kong
Keyword(s):  
Mechanical Characteristics ◽  
Shear Failure ◽  
Triaxial Tests ◽  
Cemented Sand ◽  
Optimum Water Content ◽  
Strain Relationship ◽  
Mode Stress ◽  
New Type ◽  
Sand And Gravel ◽  
Optimum Water

Cemented sand and gravel (CSG) is a new type of dam materials. It not only can reduce the waste of resources and environmental pollution, but has the merits of both gravel and concrete. In this study, Cemented sand and gravel specimens with three cement ratios were compacted at optimum water content and cured for 14 days. Based on the consolidated drained shear triaxial tests, the mechanical properties of different proportion of CSG are studied on shear failure mode, stress-strain relationship, shear strength. Research results showed that, with the increasing of the content of cement, the peak and residual strength of CSG were improved, but the failure strains were decreased. In addition, CSG material behaves distinctly softening.

scholarly journals Investigation of the Mechanical Behavior of Partially Precast Partially Encased Assembled Composite Beams

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Liufeng Zhang ◽  
Yinghua Yang
Keyword(s):  
Mechanical Properties ◽  
Composite Beam ◽  
Low Cost ◽  
Concrete Strength ◽  
Composite Beams ◽  
Test Results ◽  
Structural Form ◽  
Heavy Load ◽  
Grade Steel ◽  
Good Agreement

In view of the characteristics of a high floor and the heavy load of logistics buildings, a partially prefabricated partially encased assembled composite beam (PPEC) is proposed in order to achieve the low cost construction of such buildings. In this research, the mechanical properties of PPEC beams were studied experimentally. The effects of the concrete strength grade, steel content, shear span ratio, and fabrication methods on the mechanical properties of the PPEC beams were analyzed. The results showed that the proposed structural form of the PPEC beams was generally feasible. Based on the test results, a practical shear formula for PPEC beams was proposed, and the calculated results were in good agreement with the test results.

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