scholarly journals Experimental study on the behavior of eccentrically compressed reinforced concrete columns strengthened with CFRP composite sheets

2021 ◽  
Vol 15 (4) ◽  
pp. 172-181
Author(s):  
Trung Hieu Nguyen ◽  
Xuan Dat Pham ◽  
Khuong Duy Tran
Keyword(s):  
Experimental Study ◽  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Column Height ◽  
Strengthening Effect ◽  
Load Carrying Capacity ◽  
Rc Columns ◽  
Cfrp Sheets ◽  
Rc Column ◽  
Load Carrying

Strengthening of reinforced concrete (RC) columns is needed when the actual load-carrying capacity of the columns does not reach the required level due to either structural deterioration or increasing acting loads. This experimental study aims to evaluate the strengthening effect on the eccentrically-compressed RC columns using Carbon fiber reinforced polymer (CFRP) sheets, that confine around the column cross-section. Three RC column specimens with the same geometrical dimensions, reinforcement detailing, and concrete compressive strength were cast and tested in the current experimental investigation. One RC column without being strengthened is referred as the control specimen whereas two other RC columns were partially strengthened by CFRP sheets. All three RC columns were axially loaded with the same initial eccentricity e0 of 80 mm. Based on the test results such as the ultimate load-carrying capacity, the load-rotation relationship, and load-curvature at the middle of column height, the effectiveness of the strengthening technique is discussed.

Analysis of Seismic Performance of RC Frames with Centrally Reinforced Columns

2013 ◽  
Vol 671-674 ◽  
pp. 1319-1323
Author(s):  
Zi Xue Lei ◽  
Yu Hang Han ◽  
San Sheng Dong ◽  
Jun Qing Guo
Keyword(s):  
Seismic Performance ◽  
Cross Sections ◽  
Carrying Capacity ◽  
Pushover Analysis ◽  
Seismic Load ◽  
Load Carrying Capacity ◽  
Rc Columns ◽  
Rc Column ◽  
Rc Frames ◽  
Load Carrying

A centrally reinforced column is a new type of RC columns, formed by providing a reinforcement skeleton at the central part of the cross section of an ordinary RC column. Tests have shown that as compared with an ordinary RC column, this type of columns has a higher load carrying capacity and ductility. From the pushover analysis of a frame composed of ordinary RC columns and one consisting of centrally reinforced columns, their seismic performance under seismic load of 9-degree intensity was studied according to Chinese code, including target displacements, story-level displacements, interstory drifts, appearance and development of plastic hinges. The results indicate that although the dimensions of cross sections of columns in the frame with centrally reinforced columns are smaller than those of the ordinary frame, the former still has a higher overall load carrying capacity and seismic performance than the latter.

scholarly journals Structural Behavior of RC Column Confined by FRP Sheet under Uniaxial and Biaxial Load

Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 75
Author(s):  
Huynh-Xuan Tin ◽  
Ngo-Thanh Thuy ◽  
Soo-Yeon Seo
Keyword(s):  
Carrying Capacity ◽  
Biaxial Loading ◽  
Compressive Load ◽  
Load Carrying Capacity ◽  
Reinforced Concrete Column ◽  
Eccentric Load ◽  
Rc Columns ◽  
Rc Column ◽  
Load Carrying ◽  
Frp Sheet

Various researches have been performed to find an effective confining method using FRP sheet in order to improve the structural capacity of reinforced concrete column. However, most of these researches were undertaken for the columns subjected to concentric compressive load or fully confined RC columns. To date, it remains hard to find studies on partially FRP-confined RC columns under eccentric load. In this manner, an experimental investigation was carried out to assess the performance of rectangular RC column with different patterns of CFRP-wrap subject to eccentric loads in this paper. The experiment consists of fourteen mid-scale rectangular RC columns of 200 mm × 200 mm × 800 mm, including five controlled columns and nine CFRP-strengthened ones. All CFRP-strengthened columns were reinforced with one layer of vertical CFRP sheet with the main fiber along the axial axis at four sides, then divided into three groups according to confinement purpose, namely unconfined, partially CFRP-confined, and fully CFRP-confined group. Two loading conditions, namely uniaxially and biaxially eccentric loads, are considered as one of the test parameters. From the test of uniaxial eccentric load, partial and full CFRP-wraps provided 19% and 33% increased load-carrying capacity at an eccentricity-to-column thickness ratio (e/h) of 0.125, respectively, compared to controlled columns, and 8% and 11% at e/h = 0.25, respectively. For the partially CFRP-confined columns subjected to biaxial eccentric load with e/h = 0.125 and 0.25, the load-carrying capacities were improved by 19% and 31%, respectively. This means that the partial confinement with CFRP effectively improves the load-carrying capacity at larger biaxial eccentric load. It was found that the load-carrying capacity could be properly predicted by using code equations of ACI 440.2R-17 and Fib Bulletin 14 Guideline for the full CFRP-confined or partially CFRP-confined columns under uniaxial load. For partially CFRP-confined columns under biaxial loading, however, the safety factors using the Fib calculation process were 20% to 31% lower than that of uniaxially loaded columns.

scholarly journals Prediction of Residual Axial Load Carrying Capacity of Reinforced Concrete (RC) Columns Subjected to Extreme Dynamic Loads

2017 ◽  
Vol 10 (2) ◽  
pp. 431-448 ◽  
Author(s):  
Masoud Abedini ◽  
Azrul A. Mutalib ◽  
Sudharshan N. Raman ◽  
Shahrizan Baharom ◽  
J. Sima Nouri
Keyword(s):  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Axial Load ◽  
Dynamic Loads ◽  
Load Carrying Capacity ◽  
Rc Columns ◽  
Load Carrying

scholarly journals Experimental assessment of different strengthening techniques for opening in reinforced concrete beams

2021 ◽  
Vol 16 (59) ◽  
pp. 549-565
Author(s):  
Fatma Agag ◽  
Seleem S. E. Ahmad ◽  
Hossam El-Din M. Sallam
Keyword(s):  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymers ◽  
Load Carrying Capacity ◽  
Carbon Fiber Reinforced Polymers ◽  
Reinforced Polymers ◽  
Cfrp Sheets ◽  
Load Carrying

The present experimental study includes testing thirteen reinforced concrete beams with openings at different locations to investigate the efficiency of strengthening such openings. Different strengthening techniques around the opening after and before casting include diagonal bars, upper and lower steel, and carbon fiber reinforced polymers (CFRP), were examined. All beams were made from 30 MPa compressive strength and tested under four-point loading.  The cross section of the beams is 400 mm depth x 160 mm width and beam length 2400 mm. The dimensions of the opening are 200 mm x 200 mm. The stiffness, deflection, failure load, and failure mode of the strengthened beams were discussed. Experimental results showed that the beams strengthened with upper and lower steel around opening at mid-span increase the load-carrying capacity by 16.59%. However, beams strengthened by CFRP sheets around the opening in the shear zone increase the load carrying capacity by 47.7% compared to opened beam.

scholarly journals Structural Behavior of RC Columns Improved by Different Strengthening Techniques

2020 ◽  
Vol 28 (3) ◽  
pp. 20-28
Author(s):  
Shah Rukh Tariq ◽  
Liaqat Ali Qureshi ◽  
Babar Ali ◽  
Muhammad Usman Rashid
Keyword(s):  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Concrete Columns ◽  
Load Carrying Capacity ◽  
Cross Sectional ◽  
Rc Columns ◽  
Reinforced Concrete Columns ◽  
Existing Structures ◽  
Axial Capacity ◽  
Load Carrying

AbstractDeficient or deteriorating reinforced-concrete columns in many existing structures have to be strengthened using economical, efficient, and fast methods. In the present study, different strengthening techniques to improve the load-carrying capacity of reinforced concrete (RC) columns have been compared. Five groups of fifteen square reinforced concrete columns (150 mm × 150 mm × 600 mm) and one group of three circular columns ( φ 170 mm) that have cross-sectional areas equivalent to those of the square columns were cast from normal-strength concrete. The test program was designed to examine the behavior of columns strengthened by carbon fiber-reinforced polymer (CFRP), steel jacketing, ferro cement, steel fibers, and silica fumes under cyclic axial compression. The efficiency of each strengthening method in increasing the column’s axial capacity, energy absorption, and ductility was studied using the experimental data. The test results showed that strengthening the columns could significantly enhance their load-carrying capacity and failure strains.

scholarly journals Experimental Investigation on Seismic Behaviours of Reinforced Concrete Columns under Simulated Acid Rain Environment

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Hao Zheng ◽  
Shansuo Zheng ◽  
Yixin Zhang ◽  
Yonglong Cai ◽  
Ming Ming ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Energy Dissipation ◽  
Acid Rain ◽  
Carrying Capacity ◽  
Simulated Acid Rain ◽  
Deformation Capacity ◽  
Load Carrying Capacity ◽  
Rc Column ◽  
Visual Damage ◽  
Load Carrying

The purpose of this paper was to systematically investigate the influence of acid rain environments on the seismic behaviour of a reinforced concrete (RC) column. Six RC column specimens with shear span ratios of 2.84 were tested under low cyclic reversed loads after being subjected to accelerated corrosion tests in an artificial climate. The corrosion level and stirrup ratio were used as the control variables. The corrosion ratios of the longitudinal rebars ranged from 0 to 13.17%, and the corrosion ratios of the stirrups varied from 0 to 6.75%. The seismic behaviours of the column specimens were analysed with respect to visual damage, failure mode, hysteresis behaviour, load-carrying capacity, deformation capacity, stiffness degradation, and energy dissipation behaviour. The test results showed that the appearance characteristics of the six column specimens exhibited varying degrees of visual damage as a result of the simulated acid rain exposure. All six specimens were dominated by similar flexural-shear failures under low cyclic reversed loads, regardless of the distinctions in the corrosion levels or stirrup ratios. For the specimens with the same ratios of stirrup, as the corrosion level increased, the load-carrying capacity, deformation capacity, stiffness, and energy dissipation capacity were continuously decreased. For the specimens with the same levels of corrosion, the higher the stirrup ratio was, the stronger the restraint effect of the stirrups on the concrete, and the seismic behaviours of the specimens were obviously improved.

scholarly journals Experimental Study on the Residual Axial Load-Carrying Capacity of Shear-Damaged RC Columns

2018 ◽  
Vol 16 (2) ◽  
pp. 97-109 ◽  
Author(s):  
Yong Yang ◽  
Kazuto Matsukawa ◽  
Ho Choi ◽  
Yoshiaki Nakano
Keyword(s):  
Experimental Study ◽  
Carrying Capacity ◽  
Axial Load ◽  
Load Carrying Capacity ◽  
Rc Columns ◽  
Load Carrying
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