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1
Mohamed Sayed, Ahmed, Mohamed Mohamed Rashwan, and Mohamed Emad Helmy. "Experimental Behavior of Cracked Reinforced Concrete Columns Strengthened with Reinforced Concrete Jacketing." Materials 13, no. 12 (June 24, 2020): 2832. http://dx.doi.org/10.3390/ma13122832.
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Reinforced concrete (RC) columns often need to be strengthened or rehabilitated to allow them to carry the loads applied to them. In previous studies, RC columns have been strengthened by jacketing, without considering the occurrence of cracking. In this study, the behavior of RC columns strengthened externally by jacketing after cracking is analyzed. The accuracy of the existing models was verified by analyzing the performance of fifteen RC columns with different cross-sections to determine the effect of new variables, such as the column size, amount of steel reinforcement, and whether the column was cracked or not, on the effectiveness of strengthening. The analysis demonstrated that this strengthening technique could effectively improve both the ductility and strength of RC column cross-sections. The results indicate that the model suggested by the ACI-318 code can predict the ultimate load capacity of RC columns without strengthening, or strengthened by RC jacketing before or after cracking, with higher accuracy and material efficiency. The RC columns without strengthening met the safety limit of the ACI-318 model. However, for strengthened columns, a reduction coefficient must be used to enable the columns to meet the safety limit, with values of 94% and 76% for columns strengthened before and after cracking, respectively. Furthermore, strengthening after cracking affects the ultimate load capacity of the column, with 15.7%, 14.1%, and 13.5% lower loads for square, rectangular, and circular columns than those strengthened before cracking, respectively.
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Pei, Weichang, Daiyu Wang, Xuan Wang, and Zhenyu Wang. "Axial monotonic and cyclic compressive behavior of square GFRP tube–confined steel-reinforced concrete composite columns." Advances in Structural Engineering 24, no. 1 (July 20, 2020): 25–41. http://dx.doi.org/10.1177/1369433220934557.
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Fiber-reinforced polymer tube–confined steel fiber–reinforced concrete column is a novel composite column proposed recently, which consists of a traditional steel-reinforced concrete column and an external glass fiber–reinforced plastic tube for lateral confinement. In order to investigate the axial compression behavior of steel fiber–reinforced concrete columns, a total of 16 square specimens were fabricated and tested under axial monotonic and cyclic compressive loading. Three different configurations of inner shaped steels, including cross-shaped, box-shaped with wielding, and box-shaped without wielding were considered. Two thicknesses of glass fiber–reinforced concrete tubes were also considered as the main experimental parameters. On the basis of test results, a thorough analysis of the failure process based on strain analysis was discussed. The test results showed that steel fiber–reinforced concrete columns exhibited higher ductility and load capacity compared with fiber-reinforced plastic–confined plain concrete columns. Two quantitative indexes were proposed to measure the confinement of steel fiber–reinforced concretes. The axial cyclic mechanical behaviors were discussed through comparative analysis with monotonic behaviors. The remnant strains and modulus of the cyclic behaviors were also discussed.
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Panjwani, Prakash, and Dr S. K. DUBEY. "Study of Reinforced Concrete Beam-Column Joint." International Journal of Engineering Research 4, no. 6 (June 1, 2015): 321–24. http://dx.doi.org/10.17950/ijer/v4s6/610.
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Nhabih, Hussein Talab, Ahmed M. Hussein, and Marwa Marza Salman. "Study a Structural Behavior of Eccentrically Loaded GFRP Reinforced Columns Made of Geopolymer Concrete." Civil Engineering Journal 6, no. 3 (March 1, 2020): 563–75. http://dx.doi.org/10.28991/cej-2020-03091492.
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This study investigated a modern composite material, which is a short geopolymer concrete column (GPCC) reinforced by GFRP bars. The structural performances of GPCC subjected to eccentric load were studied and compared to the normal strength concrete column (NSCC) reinforced by steel bars. In this study, the primary experimental parameters were the reinforcement bars types, load eccentricity, and concrete types. Seven short columns were tested: three normal strength concrete columns reinforced by steel bars, three geopolymer concrete columns reinforced by GFRP bars and one normal strength concrete column without reinforcement. The model dimensions chosen in the present study was a square section of 130×130 mm and a total height of 850 mm. It was shown that the steel bars contribute about 16.47% of column capacity under concentric load. Comparing with the normal strength concrete column, a geopolymer concrete column reinforced by GFRP bars showed a little increase in ultimate load (5.17%) under concentric load. Under the load eccentricity of 130 mm, a geopolymer concrete column reinforced by GFRP bars showed a significant increase in the ultimate load (69.37%). Under large eccentricity, a geopolymer concrete column reinforced by GFRP bars has an outstanding effect on the columns' ultimate load capacity. Also, the sine form can be utilized for GPCC to find the lateral deflection along with the column high at different load values up to the failure.
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Xu, Pi Yuan, Lin Lin Ren, and Ya Feng Xu. "The Antiknock Property Research of L Steel Reinforced Concrete Special-Shaped Column in the Different Thicknesses of Steel Bone in Blast Loads." Applied Mechanics and Materials 351-352 (August 2013): 654–57. http://dx.doi.org/10.4028/www.scientific.net/amm.351-352.654.
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In this paper, L steel reinforced concrete special-shaped columns are established by the finite element analysis software ABAOUS and we simulate and analyze models in blast loads. The main purpose is to study the antiknock property of L steel reinforced concrete special-shaped column in the different thicknesses of steel bone. We change the thickness of steel bone to get the time-displacement curve of L steel reinforced concrete special-shaped columns in blast loads. On the basis of the study we draw the conclusion: the antiknock property of L steel reinforced concrete special-shaped column is better than L reinforced concrete column and with the increasing of the thickness of steel bone the antiknock property of L steel reinforced concrete special-shaped column has enhanced.
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Bao, Yanhong, Bowen Chen, and Lei Xu. "Analysis of Concrete-Filled Steel Tube Reinforced Concrete Column-Steel Reinforced Concrete Beam Plane Frame Structure Subjected to Fire." Advances in Civil Engineering 2021 (April 7, 2021): 1–12. http://dx.doi.org/10.1155/2021/6620030.
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The ABAQUS finite-element analysis platform was used to understand the mechanical behavior of concrete-filled steel tube reinforced concrete (CFSTRC) columns and steel reinforced concrete (SRC) beam plane frames under fire conditions. Thermal parameters and mechanical constitutive model of steel and concrete materials were reasonably selected, the correct boundary conditions were chosen, and a numerical model for the thermal mechanical coupling of CFSTRC columns and SRC beam plane frame structure was established. The finite-element model was verified from related experimental test results. The failure modes, deformation, and internal force distribution of the CFSTRC column and SRC beam plane frames were analyzed under ISO-834 standard fire conditions and with an external load. The influence of beam and column fire-load ratio on the fire resistance of the frame structure was established, and the fire-resistance differences between the plane frame structures and columns were compared. The CFSTRC column-steel reinforced concrete beam plane frame may undergo beam failure or the column and beam may fail simultaneously. The frame structure fire-resistance decreased with an increase of column and beam fire-load ratio. The column and beam fire-load ratio influence the fire resistance of the frames significantly. In this numerical example, the fire resistance of the frames is less than the single columns. It is suggested that the fire resistance of the frame structure should be considered when a fire-resistant structural engineering design is carried out.
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Purba, Burt K., and Aftab A. Mufti. "Investigation of the behavior of circular concrete columns reinforced with carbon fiber reinforced polymer (CFRP) jackets." Canadian Journal of Civil Engineering 26, no. 5 (October 1, 1999): 590–96. http://dx.doi.org/10.1139/l99-022.
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Recent advancements in the fields of fiber reinforced polymers (FRPs) have resulted in the development of new materials with great potential for applications in civil engineering structures, and due to extensive research over recent years, FRPs are now being considered for the design of new structures. This study describes how carbon fiber reinforced polymer jackets can be used to reinforce circular concrete columns. Fibers aligned in the circumferential direction provide axial and shear strength to the concrete, while fibers aligned in the longitudinal direction provide flexural reinforcement. Prefabricated FRP jackets or tubes would also provide the formwork for the columns, resulting in a decrease in labor and materials required for construction. Also, the enhanced behavior of FRP jacketed concrete columns could allow the use of smaller sections than would be required for conventionally reinforced concrete columns. Furthermore, FRP jacket reinforced concrete columns would be more durable than conventionally reinforced concrete columns and therefore would require less maintenance and have longer service life.Key words: bridge, carbon, column, concrete, confinement, fiber reinforced polymer, jacket, retrofitting, seismic, strengthening.
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Niu, Jiangang, Wenming Xu, Jingjun Li, and Jian Liang. "Influence of Cross-Sectional Shape on the Mechanical Properties of Concrete Canvas and CFRP-Reinforced Columns." Advances in Materials Science and Engineering 2021 (May 11, 2021): 1–14. http://dx.doi.org/10.1155/2021/5541587.
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Fiber-reinforced polymer (FRP) wrapping has become an attractive strengthening technique for concrete columns. However, the ingress of corrosion into the concrete through the gap of CFRP fiber greatly reduces the durability of concrete and the bearing capacity of specimens. Concrete canvas, a kind of corrosion-resistant and refractory material, is a promising method to enhance durability and carrying capacity. In this study, the concrete canvas (CC) and carbon fiber-reinforced polymer (CFRP) were used to jointly reinforce columns with square cross section, octagonal cross section, circular cross section, and elliptical cross section. The influence of section shape on the strengthening effect of the axial compression column was investigated by the axial compression test. The results showed that the section shape had a significant influence on the reinforcement effect of the axial compression column. The carrying load capacity and ductility coefficient of different columns follow this order: square column < oval-shaped columns < octagonal columns < circle columns. The increased amplitude of bearing capacity for the different columns with the increase of CC layers follows this order: square columns < oval-shaped columns < circle column < octagonal columns. Compared with the unconstraint columns, the bearing capacity of adopting two-layer CC columns increased by 129%, 155%, 150%, and 139% for the square, octagonal, circular, and elliptical columns, respectively. The octagonal column has the largest increase range. Compared with the unconstraint columns, the bearing capacity of adopting two-layer CC columns increased by 348%, 318%, 310%, and 296% for the square, octagonal, elliptical, and circular columns, respectively. The square column has the largest increase range. The stress concentration phenomenon of all section shapes was weakened after the CC was used. The application of the CC on CFRP-reinforced columns improves column ductility significantly, with some degree of increase in bearing capacity.
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Park, Jong Wook, Sang A. Cha, Ji Eun Kang, Mohamad Mansour, and Jung Yoon Lee. "Axial Strain of Reinforced Concrete Columns." Advanced Materials Research 163-167 (December 2010): 1858–61. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.1858.
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The reinforced concrete members are designed to fail in flexural member to behave ductilely. Also the failure doesn’t impose on columns but beams. But according to the plastic collapse mechanism, the plastic hinge potentially developed at the bottom of the RC column near the base of the structure after flexural yielding. These columns are generally dominated by shear which led to sudden failure in post yielding region because of its relatively short span-to-depth ratio, so special care is needed. The deformability of column with short span-to-depth ratio is small compared with larger span-to-depth ratio column under reversed cyclic loading. Therefore the design of these kinds of RC columns necessitates the prediction of both the shear strength after flexural yielding and corresponding ductility of such members. Ten RC columns with varying axial force ratio and shear reinforcement ratio were tested under monotonic and reversed cyclic loading. The most affectable factor to column behavior was the axial force. The result indicates that concrete contribution to shear resistance in the plastic hinge region and axial strain were decreased as axial force.
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VIRGENS, J. P., R. B. GOMES, L. M. TRAUTWEIN, G. N. GUIMARÃES, and A. P. R. VAZ. "Experimental analysis of eccentrically loaded reinforced concrete columns with an added jacket of self-compacting concrete." Revista IBRACON de Estruturas e Materiais 12, no. 2 (April 2019): 329–36. http://dx.doi.org/10.1590/s1983-41952019000200007.
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Abstract This paper presents the experimental study of eccentrically loaded reinforced concrete columns with an added 35 mm self-compacting concrete jacket attached to the column’s most compressed face using wedge bolts. Nine columns with a 2000 mm height were tested under compression and one-way bending until failure. Columns were denominated as original column (PO) with a cross section of 120 mm x 250 mm; reference column (PR) with a cross section of 155 mm x 250 mm, and seven columns with an initial cross section of 120 mm x 250 mm and later reinforced by the addition of 35 mm self-compacting concrete layer and various configurations of wedge bolts. Except for the original column PO, the columns were submitted to a 42.5 mm load eccentricity due to the added concrete layer at the compressed face. Although failure of the wedge bolts did not occur, it was not possible to prevent detachment of the added layer. The results indicate that it is possible to structurally rehabilitate reinforce concrete columns with the use of the strengthening methodology used in this research, resulting in average ultimate load capacity gains of 271% compared to original column’s ultimate load.
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Guo, Quan Quan, Yu Xi Zhao, and Kun Shang. "Experimental Research on Eccentric Compressive Performance of Steel Tube-Reinforced Concrete Column." Advanced Materials Research 163-167 (December 2010): 184–90. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.184.
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Eccentric loading experiment of 13 steel tube-reinforced concrete columns and a reinforced concrete column is implemented. The whole process from the start load on the steel tube-reinforced concrete column until damage has been researched. Change of ultimate bearing capacity with eccentricity, longitudinal reinforcement ratio, position coefficient has been studied, and deflection curve and load-vertical displacement curve under eccentric compressive load were obtained. Failure characteristics of steel tube-reinforced concrete were divided into two different type, small eccentric damage and big eccentric damage. With the same conditions, when steel tube ratio of steel tube-reinforced concrete was 2%, its ultimate bearing capacity was nearly double of reinforced concrete columns.
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Lei, Min, Zihao Wang, Penghui Li, Liyi Zeng, Hongyao Liu, Zhidong Zhang, and Huicheng Su. "Experimental Investigation on Short Concrete Columns Reinforced by Bamboo Scrimber under Axial Compression Loads." Advances in Civil Engineering 2020 (September 29, 2020): 1–12. http://dx.doi.org/10.1155/2020/8886384.
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The paper presents bamboo scrimber bars as a reinforcing material instead of steel reinforcement in low-strength concrete columns. Twelve short concrete columns with different reinforcements are tested under axial compression load to study the axial compressive behavior of short concrete columns reinforced by bamboo scrimber. Three columns are reinforced concrete columns, and the other nine columns are bamboo scrimber reinforced concrete columns. The failure process, bearing capacity, axial deformation, and strain of the specimens are compared and analyzed. The results show that the bonding performance between the bamboo scrimber bars by surface treatment and low-strength concrete is excellent. In low-strength concrete columns, the material properties of bamboo bars play more thoroughly than those of steel bars. When the bamboo reinforcement ratio is increased, the concrete column ductility is significantly improved, but the bearing capacity of the concrete column is not increased. The bamboo scrimber bars with the size of 10 mm × 10 mm or 15 mm × 15 mm can be used as longitudinal bars of low-strength concrete columns. The ductility of the short concrete column with 2.56% bamboo scrimber reinforcement is close to that of the short concrete column with 0.72% steel reinforcement.
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Elwood, Kenneth J. "Modelling failures in existing reinforced concrete columns." Canadian Journal of Civil Engineering 31, no. 5 (October 1, 2004): 846–59. http://dx.doi.org/10.1139/l04-040.
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Experimental research and post-earthquake reconnaissance have demonstrated that reinforced concrete columns with light or widely spaced transverse reinforcement are vulnerable to shear failure, and in turn, axial failure during earthquakes. Based on experimental data, failure surfaces have been used to define the onset of shear and axial failure for such columns. After the response of the column intersects the failure surface, the shear or axial strength of the column begins to degrade. This paper introduces a uniaxial material model that incorporates the failure surfaces and the subsequent strength degradation. When used in series with a beam-column element, the uniaxial material model can adequately capture the response of reinforced concrete columns during shear and axial load failure. The performance of the analytical model is compared with results from shake table tests.Key words: shear failure, axial failure, beam-column elements, failure surface, earthquakes, reinforced concrete, columns, collapse, structural analysis.
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Anand, Praveen, and Ajay Kumar Sinha. "Effect of Reinforced Concrete Jacketing on Axial Load Capacity of Reinforced Concrete Column." Civil Engineering Journal 6, no. 7 (July 1, 2020): 1266–72. http://dx.doi.org/10.28991/cej-2020-03091546.
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Whenever a member of a structure becomes structurally deficient, it becomes vulnerable to the existing load and for the additional loads that it may be subjected to in the coming future. Since columns are the most important structural element, the structural retrofit of columns, relative to other structural elements is of prime importance. This study intends to investigate the performance and behaviour of an RC column jacketed with Reinforced Concrete columns under axial loads. The objective of this paper is to find out the efficiency of RC jacket in enhancing the strength of an existing RC column. A mathematical design based upon Indian Standards codes has been designed to identify the behaviour of jacketed RC columns. This has been followed by a finite element based numerical simulation using the same material properties as used in the process of designing. The simulation has been done in ABAQUS software with appropriate contact modelling. The analytical model considers that there is no bond slippage between the existing and new concrete surface i.e. the bond between the existing and new concrete is assumed to be perfect. This perfect bond between the surfaces has been modelled by using appropriate constraints in ABAQUS software. The finite element models show fair agreement with the designed values in terms of ultimate capacity and failure mode. The load bearing capacity enhancement of the RC jacketed column has been found to increase substantially. The enhancement capacity results obtained from the finite element software differs about 16-25% from the design values.
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Tian, Jia Jia, and Hong Li. "The Influence of Vertical Loads on Lateral Deformation of Steel Reinforced Concrete Column." Advanced Materials Research 639-640 (January 2013): 782–85. http://dx.doi.org/10.4028/www.scientific.net/amr.639-640.782.
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The influence of vertical loads on steel reinforced concrete column is analyzed, based on the maximum lateral displacement of 2 different steel reinforced concrete columns under different vertical loads. The vertical loads, the section properties of the steel reinforced concrete column and horizontal loads are the influencing factors.
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FERREIRA, D. B., R. B. GOMES, A. L. CARVALHO, and G. N. GUIMARÃES. "Behavior of reinforced concrete columns strenghtened by partial jacketing." Revista IBRACON de Estruturas e Materiais 9, no. 1 (February 2016): 1–21. http://dx.doi.org/10.1590/s1983-41952016000100002.
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This article presents the study of reinforced concrete columns strengthened using a partial jacket consisting of a 35mm self-compacting concrete layer added to its most compressed face and tested in combined compression and uniaxial bending until rupture. Wedge bolt connectors were used to increase bond at the interface between the two concrete layers of different ages. Seven 2000 mm long columns were tested. Two columns were cast monolithically and named PO (original column) e PR (reference column). The other five columns were strengthened using a new 35 mm thick self-compacting concrete layer attached to the column face subjected to highest compressive stresses. Column PO had a 120mm by 250 mm rectangular cross section and other columns had a 155 mm by 250mm cross section after the strengthening procedure. Results show that the ultimate resistance of the strengthened columns was more than three times the ultimate resistance of the original column PO, indicating the effectiveness of the strengthening procedure. Detachment of the new concrete layer with concrete crushing and steel yielding occurred in the strengthened columns.
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Aryan, Hadi. "Seismic Resistant Bridge Columns with NiTi Shape Memory Alloy and Ultra-High-Performance Concrete." Infrastructures 5, no. 12 (November 30, 2020): 105. http://dx.doi.org/10.3390/infrastructures5120105.
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Reinforced concrete bridge columns often endure significant damages during earthquakes due to the inherent deficiencies of conventional materials. Superior properties of the new materials such as shape memory alloy (SMA) and ultra-high-performance concrete (UHPC), compared to the reinforcing steel and the normal concrete, respectively, are needed to build a new generation of seismic resistant columns. Application of SMA or UHPC in columns has been separately studied, but this paper aims to combine the superelastic behavior of NiTi SMA and the high strength of UHPC, in order to produce a column design with minimum permanent deformation and high load tolerance subjected to strong ground motions. Additionally, the excellent corrosion resistance of NiTi SMA and the dense and impermeable microstructure of UHPC ensure the long-term durability of the proposed earthquake resistant column design. The seismic performance of four columns, defined as steel reinforced concrete (S-C), SMA reinforced concrete (SMA-C), SMA reinforced UHPC (SMA-UHPC), and reduced SMA reinforced UHPC (R-SMA-UHPC) is analyzed through a loading protocol with up to 4% drift cycles. The use of NiTi SMA bars for the SMA reinforced columns is limited to the plastic hinge region where permanent deformations happen. All the columns have 2.0% reinforcement ratio, except the R-SMA-UHPC column that has a 1.33% reinforcement ratio to optimize the use of SMA bars. Unlike the S-C column that showed up to 68% residual deformation compared to peak displacement during the last loading cycle the SMA reinforced columns did not experience permanent deformation. The SMA-C and R-SMA-UHPC columns showed similar strengths to the S-C column, but with about 5.0- and 6.5-times larger ductility, respectively. The SMA-UHPC column showed 30% higher strength and 7.5 times larger ductility compared to the S-C column.
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Liu, Xue Feng, Qing Xin Ren, and Lian Guang Jia. "Temperature Field Analysis of Concrete Filled Steel Tube Reinforced Concrete Columns in Fire." Applied Mechanics and Materials 644-650 (September 2014): 5019–22. http://dx.doi.org/10.4028/www.scientific.net/amm.644-650.5019.
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In this paper, temperature field analysis of concrete filled steel tube reinforced concrete columns in fire has been carried on. A finite element model for concrete filled steel tube reinforced concrete columns in fire is developed by ABAQUS. The cross-sectional temperature field distribution regularity of concrete filled steel tube reinforced concrete columns in fire has been obtained. Parameter analysis such as fire duration time and steel ratio on the column section temperature field is conducted, and this provide the reference for the further analysis of concrete filled steel tube reinforced concrete columns.
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Urban, Tadeusz, Michał Gołdyn, and Łukasz Krawczyk. "Experimental investigations of reinforced concrete columns in the edge connection zone with a reinforced concrete slab." Budownictwo i Architektura 13, no. 3 (September 11, 2014): 175–82. http://dx.doi.org/10.35784/bud-arch.1814.
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In this paper the results of the experimental investigations of edge column – slab connections are presented and commented on. The load transmission mechanism between high strength concrete columns and slab made of normal, five times lower strength concrete was considered. The variable parameter of presented study was the overhang of slab cantilever. The performed study showed important effect of slab cantilever on effective concrete strength of column in the connection zone.
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Rodsin, Kittipoom. "Ductility Enhancement of High Strength RC Columns Using Steel Fiber Reinforced Concrete (SFRC)." Advanced Materials Research 931-932 (May 2014): 463–67. http://dx.doi.org/10.4028/www.scientific.net/amr.931-932.463.
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The principal aim of this research is to improve the seismic performance of high strength concrete (HSC) reinforced columns using fiber reinforced concrete (FRC) by mixing steel fiber into the concrete. Two reinforced concrete columns 200mm x 300mm in cross-section with a height of 1250 mm were tested under cyclic lateral loading. The first specimen was casted using high strength concrete of 100 MPa and the second specimens were also casted using similar concrete strength but the steel fiber of 0.5% by volume was added to the concrete in the plastic hinge region. Both columns were subjected to lateral cyclic load until the failure occurs. The test results showed that the use of FRC in the plastic hinge region could significantly improve column displacement ductility. The maximum drift at column failure at 4.5% for non-ductile column could increase to 8% in FRC column. It is evident that the cracks in FRC column are much smaller properly spread in the plastic hinge region and hence the plastic hinge could be able to rotate without lateral strength being compromised. In FRC column, concrete spalling was observed in a very high drift (7%) and bar buckling occurred at around 8% drift whilst in HSC column concrete spalling and bar buckling occurred at only 3.5% and 4% drift respectively. It was evident that the use of steel fiber in HSC columns could significantly improve seismic performance of the column.
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Park, Robert. "Ductile Design Approach for Reinforced Concrete Frames." Earthquake Spectra 2, no. 3 (May 1986): 565–619. http://dx.doi.org/10.1193/1.1585398.
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In the design of multistorey moment-resisting reinforced concrete frames to resist severe earthquakes the emphasis should be on good structural concepts and detailing of reinforcement. Poor structural concepts can lead to major damage or collapse due to column sidesway mechanisms or excessive twisting as a result of soft storeys or lack of structural symmetry or uniformity. Poor detailing of reinforcement can lead to brittle connections, inadequate anchorage of reinforcement, or insufficient transverse reinforcement to prevent shear failure, premature buckling of compressed bars or crushing of compressed concrete. In the seismic provisions of the New Zealand concrete design code special considerations are given to the ratio of column flexural strength to beam flexural strength necessary to reduce the likelihood of plastic hinges forming simultaneously in the top and bottom of columns, the ratio of shear strength to flexural strength necessary to avoid shear failures in beams and columns at large inelastic deformations, the detailing of beams and columns for adequate flexural strength and ductility, and the detailing of beams, columns and beam-column joints for adequate shear resistance and bar anchorage. Differences exist between current United States and New Zealand code provisions for detailing beams and columns for ductility and for the design of beam-column joints.
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Gramblička, Štefan, and Peter Veróny. "Transverse Reinforcement in Reinforced Concrete Columns." Selected Scientific Papers - Journal of Civil Engineering 8, no. 2 (November 1, 2013): 41–50. http://dx.doi.org/10.2478/sspjce-2013-0017.
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Abstract In the article we are dealing with the influence of transverse reinforcement to the resistance of a cross-section of the reinforced concrete columns and also with the effective detailing of the column reinforcement. We are verifying the correctness of design guides for detailing of transverse reinforcement. We are also taking into account the diameter of stirrups and its influence over transverse deformation of column.
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Krutii, Yurii, Anatolii Kovrov, Yurii Otrosh, and Mykola Surianinov. "Analysis of Forced Longitudinal Vibrations of Columns Taking into Account Internal Resistance in Resonance Zones." Materials Science Forum 1006 (August 2020): 79–86. http://dx.doi.org/10.4028/www.scientific.net/msf.1006.79.
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In analytical form, formulas are obtained for the amplitude of forced harmonic longitudinal vibrations of reinforced concrete and fiber-reinforced concrete columns with fixed edges. In order to verify the proposed approach, columns were simulated in the ANSYS program and calculated by the finite element method. Analysis of the calculations shows that a significant raise in the amplitude of the forced vibrations is observed only in the region of the first resonant frequency. It has been established that the value of the maximum amplitude of the vibrations of the fiber reinforced concrete column is 16% less than that for a reinforced concrete column.
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Chiang, J. C. L., and Leong Wai Lim. "Behaviour and Strengthening Methods of Tall Slender Columns in Earthquake Conditions." Key Engineering Materials 879 (March 2021): 221–31. http://dx.doi.org/10.4028/www.scientific.net/kem.879.221.
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Reinforced concrete buildings are normally designed and constructed with well-defined vertical column supports which are able to withstand both vertical and lateral loadings. In the case of high columns there is a risk of instability due to its slenderness caused by the higher apex ratio (measured by its height in relation to the width). This is compounded by having such buildings located at medium to high seismic risk zones, where lateral dynamic loadings can occur. This research paper focused on how such slender reinforced concrete columns will behave under earthquake loading conditions, and highlights some innovative ways to strengthen the column capacity to withstand both vertical and lateral loadings. Besides the conventional ways to provide diagonal or lateral bracings, the use of glass fibre reinforced polymer (GFRP) as an alternative material for retrofitting tall slender reinforced concrete columns are presented here. The new method includes spraying of the GFRP onto the external surfaces of the columns and also incorporate the GFRP bars as additional reinforcement into the concrete columns. Both methods proved to improve the durability and strengthen the tall reinforced concrete column. This study shows the ability of the new method of amelioration of the slender reinforced concrete columns to increase their stability during seismic activity.
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Qi, Yue. "Experimental Research on Bearing Capacity of Concrete Columns with High Strength Concrete Core under Axial Compression Loading." Advanced Materials Research 479-481 (February 2012): 2041–45. http://dx.doi.org/10.4028/www.scientific.net/amr.479-481.2041.
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Based on experimental research on plain concrete columns with high strength concrete core, the formula to predict the bearing capacity of concrete columns with high strength concrete core under axial compression loading was brought forward in previous paper, in order to verify the formula whether right, axial compression test including 3 concrete columns with high strength concrete core and 1 ordinary reinforced concrete column were completed, and the failure characteristic was analyzed additionally. According to experimental results, it can be shown that the failure modes of concrete columns with high strength concrete core are similar to that of ordinary reinforced concrete columns, however, the bearing capacity of concrete columns with high strength concrete core is significant higher compared with that of ordinary reinforced concrete column; the results of the bearing capacity obtained by the formula (2) was in good agreement with the experimental results.
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Tian, Peng, Xu Dong Shi, Yuan Qing Wang, and Yan Nian Zhang. "Mechanical Behavior Analysis of Reinforced Concrete Column Strengthening with Shear Wall." Applied Mechanics and Materials 438-439 (October 2013): 696–700. http://dx.doi.org/10.4028/www.scientific.net/amm.438-439.696.
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This paper studies the influences of factors such as axial compressive ratio and shear wall thickness on the mechanical performance of the reinforced concrete column strengthening with shear wall under low-cyclic reversed loading. Considering the secondary stress characteristics of the strengthening column, a numerical analysis was made on the load displacement hysteretic curve and skeleton curve. The results show that, with the increasing of axial compression ratio, the bearing capacity and stiffness of reinforced concrete column increased, but the ductility of reinforced column reduced; the bearing capacity and rigidity of reinforced column strengthening with shear wall increase while the ductile was lower; the change of shear wall thickness has a little effect on the bearing capacity, but improves the energy dissipation capacity of reinforced concrete columns.
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Cheung, P. C., T. Paulay, and R. Park. "Some possible revisions to the seismic provisions of the New Zealand concrete design code for moment resisting frames." Bulletin of the New Zealand Society for Earthquake Engineering 25, no. 1 (March 31, 1992): 37–43. http://dx.doi.org/10.5459/bnzsee.25.1.37-43.
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Possible revisions to the seismic design provisions of the New Zealand concrete design code NZS 3101: 1982 for ductile reinforced concrete moment resisting frames are discussed. Topics include shear reinforcement for beam-column joint cores, anchorage of longitudinal reinforcement passing through beam-column joint cores, and transverse reinforcement in columns for confinement in potential plastic hinge regions of columns. The recommendations are based on recent experimental and theoretical studies of the simulated seismic response of beam-column joints and columns in ductile reinforced concrete frames. Rational models for the evaluation of behaviour are presented.
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Liu, Jin Ming. "Construction Technology of Lift Slab with Concrete Filled Steel Tube Columns." Applied Mechanics and Materials 170-173 (May 2012): 3072–76. http://dx.doi.org/10.4028/www.scientific.net/amm.170-173.3072.
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Abstract. This paper discusses a lift slab building with concrete filled steel tube columns. Lift slab construction as a methodology has advanced on improvements in traditional lift slab construction technology. When concrete filled steel tube columns are used, the strength of the concrete in the tube is obviously enhanced by the hoop action derived from the steel tube. The section of the concrete filled steel tube column is smaller than the section of the reinforced concrete column, thus realizing cost savings in material and labor. Also, because the steel tube hasn’t been filled with concrete when it is assembled, the steel tube is much lighter than the traditional reinforced concrete column. Thus, the assembly of steel tube columns without concrete is easier and crane-lifting requirements are less. This paper describes the construction of a building utilizing current LSCSTC – Lift Slab Construction with Concrete filled Steel Tube Column technology.
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Dariienko, Viktor, Dmytro Artemenko, Olexandr Lizunkov, and Oleh Plotnikov. "Results of Numerical Modeling the Stress-Strain State of Damaged Reinforced Concrete Columns in the Middle Row of the Industrial Building." Materials Science Forum 968 (August 2019): 342–47. http://dx.doi.org/10.4028/www.scientific.net/msf.968.342.
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The article is devoted to the investigation of the influence of columns’ concrete body destruction size on the bearing capacity of building structures. The joint spatial work of steel strengthening structures with reinforced concrete constructions is investigated. The results of numerical modeling the stress-strain state of damaged reinforced concrete columns in the middle row of the industrial building are presented. The numerical modeling was executed in the system NASTRAN. It was carried out the numerical calculation of reinforced concrete column in the middle row without damages. Then it was modeled the column damage in form of a "downed" concrete angle to a depth of 50, 100 and 200 mm and denudation of bearing longitudinal armature at length of 1000 mm from supporting part of the column. In this case two separate models were investigated - with the location of damage from the compressed or extended side of the column. The conclusions about feasibility of columns strengthening by steel clip are made.
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Kim, Tae-Hoon, Young-Jin Kim, Hyeong-Taek Kang, and Hyun Mock Shin. "Performance assessment of reinforced concrete bridge columns using a damage index." Canadian Journal of Civil Engineering 34, no. 7 (July 1, 2007): 843–55. http://dx.doi.org/10.1139/l07-003.
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A procedure is presented for assessment of the performance of reinforced concrete bridge columns. Fourteen circular reinforced concrete bridge columns were tested under a constant axial load and a cyclically reversed horizontal load. A computer program, named RCAHEST (reinforced concrete analysis in higher evaluation system technology), was used to analyze these reinforced concrete structures. A damage index based on the predicted hysteretic behavior of a reinforced concrete bridge column was used. Damage indices aim to provide a means of quantifying numerically the performance level of reinforced concrete bridge columns under earthquake loading. The proposed numerical method for the performance assessment of reinforced concrete bridge columns was verified by comparison with the experimental results. Key words: assessment procedure, reinforced concrete bridge columns, damage index, hysteretic behavior, performance level.
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Zhang, Yun Feng, Shou Kang Liu, and De Wang Zhao. "Experimental Research on the Effects of Pipe Diameter on Axial Compression Properties of GFRP Tubes Reinforced Concrete Column." Applied Mechanics and Materials 204-208 (October 2012): 972–77. http://dx.doi.org/10.4028/www.scientific.net/amm.204-208.972.
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Through the axial compression experiment of 9 GFRP tubes reinforced concrete columns, this paper analyzes the failure mode and loading-strain curves under different pipe diameter, and compares bearing capacity between the experimental data with FRP reinforced concrete and the calculated value without GFRP tubes reinforced concrete. he results show that the bearing capacity and ductility of GFRP tubes reinforced concrete column have improved, because of the restriction effect of FRP tubes. The confining ability of FRP tubes on concrete reduced for a certain thickness GFRP tubes constraint concrete short column, while the pipe diameter is increasing.
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Al-Hazragi, Abd-al-Salam, and Assim Lateef. "Behaviour of Uniaxial Reinforced Concrete Columns Strengthened with Ultra-High Performance Concrete and Fiber Reinforced Polymers." Tikrit Journal of Engineering Sciences 28, no. 2 (May 5, 2021): 54–72. http://dx.doi.org/10.25130/tjes.28.2.05.
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This article investigates the behaviour of strengthened concrete columns using jacketing ultra-high-performance fiber reinforced concrete (UHPFRC) and carbon fiber-reinforced polymer (CFRP) under uniaxial loaded. The jacket was connected to the column core using shear connectors and (CFRP) fixed as a strip on the tension zone between the column cores and the jacketing. Seven column samples of square cross-section (120 x120) mm at the midsection with overall length of 1250 mm were cast using normal strength concrete (NSC) and having similar longitudinal and transverse reinforcement. The samples were made and tested under axial load at eccentricity equal to 120 mm up to failure. Test parameters were the thickness of jackets (25 and 35) mm and the width of CFRP (0,8, and 12) cm. Column specimens were tested, one of them was reference without any strengthening, and the other specimens divided into two groups (A, and B), and each group included three specimens based on the parameters. Group (A) has UHPFRC jacket thickness 25 mm and CFRP width (0,8, and 12) cm respectively, and group (B) has UHPFRC jacket thickness 35 mm and CFRP width (0,8, and 12) cm respectively. The outcomes of the article show that increasing the thickness of jacket, and width of CFRP lead to increase in the load carrying capacity about (110.5%,168.4%, and 184.2%) for group A, and (157.9%,226.3%, and 263.2%) for group B compared with the reference column due to delay in the appearance of cracks and their distribution. The mid-height lateral displacement of columns was decreased about (66.6%,42.3%, and 35.9%) for group A, and (46.15%,38.46%, and 32.3%) for group B, also the axial deformation of specimens decreased about (71.7%,60.86%, and 55.86%) for group A, and (65.5%,60.5%, and 53.4) for group B compared with the reference column. The ductility of columns that were strengthened with UHPFRC jacket only was increased about (13.67%,19.66%) for thickness(25,35) mm respectively, because of that UHPFRC jacket was contented on steel fibers, and the percentage decrease of ductility was about (5.1%,and 12%) for group (A), (1%,and 9.4%) for group (B) when bonded CFRP in the tension zone with width (8 ,and 12) cm respectively. The results show improvement in the initial and secant stiffness when, increased the thickness of jacket, and width of CFRP because of increase in the size of columns and improvement in the modulus of elasticity. The toughness increase was about (273.97%,301.55%, and 304.5%) for group A, and (453.69%,511.93%, and 524.28%) for group B compared with the reference column because of increase in the size of specimens and delay the appearance of cracks.
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Al-Hazragi, Abd-al-Salam, and Assim Lateef. "Behaviour of Uniaxial Reinforced Concrete Columns Strengthened with Ultra-High Performance Concrete and Fiber Reinforced Polymers." Tikrit Journal of Engineering Sciences 28, no. 2 (March 20, 2021): 54–72. http://dx.doi.org/10.25130/tjes.28.02.05.
Full textAbstract:
This article investigates the behaviour of strengthened concrete columns using jacketing ultra-high-performance fiber reinforced concrete (UHPFRC) and carbon fiber-reinforced polymer (CFRP) under uniaxial loaded. The jacket was connected to the column core using shear connectors and (CFRP) fixed as a strip on the tension zone between the column cores and the jacketing. Seven column samples of square cross-section (120 x120) mm at the midsection with overall length of 1250 mm were cast using normal strength concrete (NSC) and having similar longitudinal and transverse reinforcement. The samples were made and tested under axial load at eccentricity equal to 120 mm up to failure. Test parameters were the thickness of jackets (25 and 35) mm and the width of CFRP (0,8, and 12) cm. Column specimens were tested, one of them was reference without any strengthening, and the other specimens divided into two groups (A, and B), and each group included three specimens based on the parameters. Group (A) has UHPFRC jacket thickness 25 mm and CFRP width (0,8, and 12) cm respectively, and group (B) has UHPFRC jacket thickness 35 mm and CFRP width (0,8, and 12) cm respectively. The outcomes of the article show that increasing the thickness of jacket, and width of CFRP lead to increase in the load carrying capacity about (110.5%,168.4%, and 184.2%) for group A, and (157.9%,226.3%, and 263.2%) for group B compared with the reference column due to delay in the appearance of cracks and their distribution. The mid-height lateral displacement of columns was decreased about (66.6%,42.3%, and 35.9%) for group A, and (46.15%,38.46%, and 32.3%) for group B, also the axial deformation of specimens decreased about (71.7%,60.86%, and 55.86%) for group A, and (65.5%,60.5%, and 53.4) for group B compared with the reference column. The ductility of columns that were strengthened with UHPFRC jacket only was increased about (13.67%,19.66%) for thickness(25,35) mm respectively, because of that UHPFRC jacket was contented on steel fibers, and the percentage decrease of ductility was about (5.1%,and 12%) for group (A), (1%,and 9.4%) for group (B) when bonded CFRP in the tension zone with width (8 ,and 12) cm respectively. The results show improvement in the initial and secant stiffness when, increased the thickness of jacket, and width of CFRP because of increase in the size of columns and improvement in the modulus of elasticity. The toughness increase was about (273.97%,301.55%, and 304.5%) for group A, and (453.69%,511.93%, and 524.28%) for group B compared with the reference column because of increase in the size of specimens and delay the appearance of cracks.
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Souza, Régis Marciano de, Ricardo Rodrigues Magalhães, and Ednilton Tavares de Andrade. "COMPARATIVE STUDY OF NON-LINEAR SIMULATIONS OF A REINFORCED CONCRETE SLENDER COLUMN USING FINITE ELEMENT METHOD AND P-DELTA." Theoretical and Applied Engineering 3, no. 1 (February 11, 2019): 1–11. http://dx.doi.org/10.31422/taae.v3i1.7.
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This paper analyzes the non-linear geometric behavior of reinforced concrete slender columns. This approach is due to the fact that there is a tendency to reinforced concrete slender constructions, which may have significant second order effects. This research aimed at comparing different formulations for the analysis of non-linear behavior of reinforced concrete slender columns by comparing results from simulated problem (slender column with ten load scenarios) between the Finite Element Method (FEM) and the Iterative Process P-DELTA(P-Δ). Numeric results revealed that the Iterative Process P-Δ presented different results from FEM and that the second order effects are significant for reinforced concrete slender column problems.
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Elaldi, Faruk, Batuhan Ciloglu, and Yasin Yanikkaya. "A Comparison on Column Reinforcement with Conventional Concrete and Carbon Fiber / Epoxy Exposed to Compression Loading." Solid State Phenomena 305 (June 2020): 85–90. http://dx.doi.org/10.4028/www.scientific.net/ssp.305.85.
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There are lots of concrete columns and beams around in our living cities. Those items are mostly open to aggressively environmental conditions. Mostly, they are deteriorated by sand wind, humidity and other external applications. After a while these beam and columns need to be repaired. Within the scope of this study, for reinforcement of concrete columns, samples were designed and fabricated to be strengthened with carbon fiber reinforced composite materials and conventional concrete encapsulation and followed by, they were put into the axial compression test to determine load carrying performance before column failure. In the first stage of this study, concrete column design and mold designs were completed for a certain load carrying capacity. Later, the columns were exposed to environmental deterioration in order to reduce load carrying capacity. To reinforce these damaged columns, two methods were applied, the one “concrete encapsulation” and the other one “wrapping with carbon fiber /epoxy” material. In the second stage of the study, the reinforced columns were applied to axial compression test and the results obtained were analyzed. Cost and load carrying performance comparisons were made and it is found that even though carbon fiber/epoxy reinforced method is more expensive, this method enhances higher load carrying capacity and reduces reinforcement processing period.
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Li, Qiang, Zhong Gou Chen, and Dan Wu. "Temporal and Spatial Evolution of Acoustic Emission in the Damage Process of Reinforced Concrete Column." Applied Mechanics and Materials 638-640 (September 2014): 275–78. http://dx.doi.org/10.4028/www.scientific.net/amm.638-640.275.
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To study the whole process of fracture and damage of reinforced concrete column, temporal and spatial evolution of acoustic emission in the damage process of reinforced concrete column were tested. The results show that AE events of corroded column were much more during the whole loading process than that of the none-corroded one due to reinforcement corrosion. At the same loading speed, the corroded column was failed earlier than the none-corroded one. AE can obtain the internal temporal and spatial evolution damage parameters of the reinforced concrete members before the macro crack visible. The AE results were in well agreement with the brittle failure of both corroded and none-corroded columns. 3D location of AE events can directly reflect the fracture and failure process of reinforced concrete column but its accuracy needs further study.
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Landović, Aleksandar, and Miroslav Bešević. "Experimental Research on Reinforced Concrete Columns Strengthened with Steel Jacket and Concrete Infill." Applied Sciences 11, no. 9 (April 29, 2021): 4043. http://dx.doi.org/10.3390/app11094043.
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Experimental research on axially compressed columns made from reinforced concrete (RC) and RC columns strengthened with a steel jacket and additional fill concrete is presented in this paper. A premade squared cross-section RC column was placed inside a steel tube, and then the space between the column and the tube was filled with additional concrete. A total of fourteen stub axially compressed columns, including nine strengthened specimens and five plain reinforced concrete specimens, were experimentally tested. The main parameter that was varied in the experiment was the compressive strength of the filler concrete. Three different concrete compression strength classes were used. Test results showed that all three cross-section parts (the core column, the fill, and the steel jacket) worked together in the force-carrying process through all load levels, even if only the basic RC column was loaded. The strengthened columns exhibited pronounced ductile behavior compared to the plain RC columns. The influence of the test parameters on the axial compressive strength was investigated. In addition, the specimen failure modes, strain development, and load vs. deformation relations were registered. The applicability of three different design codes to predict the axial bearing capacity of the strengthened columns was also investigated.
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Xu, Ying, Chengyin Liu, Lei Chai, Miaomiao Lu, and Congcong Luo. "Failure mechanism of fiber-reinforced polymer-confined concrete column with initial defects." Journal of Composite Materials 52, no. 21 (February 19, 2018): 2887–97. http://dx.doi.org/10.1177/0021998318758882.
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The effect of initial defect size on the mechanical behavior and failure mode of carbon fiber-reinforced polymer- confined concrete column was investigated through theoretical analysis, finite element software simulation and experiment validation. Qualitative theoretical analysis was firstly explored to study the effect of initial defect size on the mechanical behavior of confined concrete column from macro to micro perspective. Numerical simulations and experimental investigation were then carried out and compared to investigate the mechanical behavior of carbon fiber-reinforced polymer-confined concrete column with initial defects under axial compression and eccentric compression. The variation of defect criticality was investigated by varying the layer number of carbon fiber-reinforced polymer and cross-section size of concrete columns. The effect of initial defect size on the failure mode of carbon fiber-reinforced polymer-confined concrete column was finally demonstrated.
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Xue, Jian Yang, Jian Peng Lin, and Hui Ma. "Experimental Study on Seismic Performance of Steel Reinforced Recycled Concrete Column." Applied Mechanics and Materials 501-504 (January 2014): 1580–86. http://dx.doi.org/10.4028/www.scientific.net/amm.501-504.1580.
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The pseudo-static tests were carried out on seven steel reinforced recycled concrete columns. The main parameters of specimens were recycled aggregate replacement ratio, axial compression ratio and volumetric stirrup ratio. The results indicate that the incorporation of recycled aggregate doesnt reduce the horizontal bearing capacity, ductility and the energy dissipation capacity of specimens and has little effect on seismic performance. The seismic performance of steel reinforced recycled concrete column decreases significantly in the high axial compression ratio. The ductility, horizontal bearing capacity and the energy dissipation capacity of the steel reinforced recycled concrete column increase with a rise in the volumetric stirrup ratio. This study provides a reference on the application of the steel reinforced recycled concrete column.
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Al-Mashaykhi, Mustafa, Belal Alsubari, Mazin Abdulrahman, and Aayat Hussein. "Punching Strength of Reactive Powder Reinforced Concrete Flat Slabs." TJES: Vol. 28, No.3 28, no. 3 (April 7, 2021): 35–74. http://dx.doi.org/10.25130/tjes.28.3.03.
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This research is devoted to investigating experimentally the punching shear strength of reactive powder concrete slabs under monotonic loading. All slabs have the same flexural reinforcement and same dimensions (1000mm length,600mm width,50mm thickness). The experimental program includes casting and testing of sixteen slabs tested under monotonic loading. The major parameters adopted in the current research include the shape of column (circle, square), column size (twocolumn sizes), number of columns (one, two), and the distance between two columns (3d,5d,7d). Results showed that, the slabs with circular column sections have slightly higher ultimate load than those with square column sections. An increasing column area increases the load of punching shear failure. It was found that the ultimate failure load for slabs with two columns is greater than the slabs with one column. Related to the effect of distance between the two columns for monotonic, it was found that the slabs maximum load reaches the maximum value at distance between the two columns equal to(7d) for a circular section with a diameter of 85mm and 113mm and square section with dimensions of (100*100)mm. While the maximum failure load reaches the maximum value when the distance between two columns (d) for a square section with the dimension of (75*75)mm. Related to the crack patterns, it was noticed that for slabs with larger columns sections with the distance between columns equal to 7d, the failure zone extended (in a large direction) to the slab sides.
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Kim, Heung Youl, Hyung Jun Kim, Kyung Hoon Park, Bum Youn Cho, and Jae Sung Lee. "Fire Resistance Performance of High-Strength Concrete Columns Reinforced with Pre-Stressed Wire Ropes." Applied Mechanics and Materials 470 (December 2013): 880–83. http://dx.doi.org/10.4028/www.scientific.net/amm.470.880.
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In this study, the fire resistance performance of high-strength concrete columns was evaluated to see the influence of lateral confinement reinforcement with wire ropes for improving ductility, fire resistance reinforcement with fiber cocktail and load ratio. For this, loaded fire test was conducted under ISO834 standard fire condition. The axial ductility of the 60MPa high-strength concrete column reinforced with pre-stressed wire ropes was improved and its fire resistance performance was also improved by 23% compared with its counterpart without wire ropes. The appropriate load for the 60MPa concrete column reinforced with wire ropes was found to be 70% of design load. The fire resistance performance of the 100MPa high-strength concrete column reinforced with pre-stressed wire ropes and fiber-cocktail was improved as much as 4 times compared with that reinforced with tie bars only. The appropriate load for the 100MPa columns was found to be less than 70% of design load in order for the columns to secure required fire resistance performance.
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Li, Xiaobin, Hongwei Xie, Meng Yan, Hongye Gou, Gangyun Zhao, and Yi Bao. "Eccentric Compressive Behavior of Reinforced Concrete Columns Strengthened Using Steel Mesh Reinforced Resin Concrete." Applied Sciences 8, no. 10 (October 5, 2018): 1827. http://dx.doi.org/10.3390/app8101827.
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Rapid strengthening is focused on recently to reduce the time for reinforcement process and decrease the losses. However, there are some limits for the existing reinforcement technologies to be used for rapid strengthening. The paper reports an experimental investigation on eccentric compressive behavior of reinforced concrete columns that are strengthened using steel mesh reinforced resin concrete (SMRC) for rapid strengthening. Four reinforced concrete columns with 180 mm × 250 mm test cross section and 1000 mm test height were fabricated and tested under large eccentric compressive load. Among the four columns, three columns were strengthened using SMRC with different numbers of steel mesh layers; the other column was not strengthened and was used as the control specimen. The effect of layer number of steel mesh on the failure mode, cracking load and load capacity of the columns were studied. Finite element analysis was carried out to evaluate the effects of the layer number of steel mesh, thickness of SMRC layer, and the load-holding level on the load capacity of the columns. Results show that the crack distribution of the strengthened columns was influenced by the layer number of steel mesh. The layer number was the dominant variable for the load capacity, rather than the thickness of the SMRC layer. With the increase of load-holding level, the load capacity of the strengthened column decreased following a bilinear trend. Some conclusions can be drawn that the reasonable reinforcement ratio of steel mesh is about 2%. Resin concrete is mainly used as bonding layer. The decreasing rate of the bearing capacity is higher at the high load-holding levels.
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Zhang, Guo Xue, Chang Wei Wang, and Zhi Hao Zhang. "Strength Degradation and Energy Dissipation of Stainless Steel Reinforced Concrete Columns." Applied Mechanics and Materials 90-93 (September 2011): 1614–17. http://dx.doi.org/10.4028/www.scientific.net/amm.90-93.1614.
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Three specimens with ribbed stainless steel rebar and one specimen with ribbed ordinary steel rebar are tested concerning the strength degradation and energy dissipation of stainless steel reinforced concrete columns. The tests results indicate that the damage of the specimens exhibit ductile failure characteristics, and the reinforced concrete columns with stainless steel rebar damage to a lesser extent, appear good ductility and energy dissipation. The strength degradation of stainless steel reinforced column with high axial compression ratio is quite obvious, and with the increasing of the stirrup ratio of column with stainless steel rebar, the strength of column is enhanced.
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Kittipoom, Rodsin, Sappakittipakorn Manote, and Sukontasukkul Piti. "Seismic Performance Enhancement of Non-Ductile RC Columns Using Steel Fiber Reinforced Concrete (SFRC)." Advanced Materials Research 747 (August 2013): 773–76. http://dx.doi.org/10.4028/www.scientific.net/amr.747.773.
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The principal aim of this research is to improve the seismic performance of non-ductile reinforced columns using fiber reinforced concrete (FRC) by mixing steel fiber into the concrete. Two reinforced concrete columns 200mm x 300mm in cross-section with a height of 1250 mm were tested under cyclic lateral loading. The first specimen was casted using normal strength concrete of 24 MPa and the second specimens were also casted using similar concrete with similar strength but the steel fiber of 1% was added to the concrete in the plastic hinge region. The axial load for all specimens was 300 kN and kept constant during the test. The test results showed that the use of FRC in the plastic hinge region could significantly improve column displacement ductility. The maximum drift at lateral strength loss at 3.7% for non-ductile column could increase to 6% in FRC column. It is evident that the cracks in FRC column are much smaller and more widely spread in the plastic hinge region and hence the plastic hinge could be able to rotate without lateral strength being compromised. In FRC column, concrete spalling was observed in a very high drift (5%) and bar buckling occurred at around 6% drift whilst in non-ductile column concrete spalling and bar buckling occurred at 2.5% and 3% drift respectively. It was evident that the use of steel fiber in non-ductile columns could significantly improve seismic performance of the column.
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Hranilović, Igor, Darko Meštrović, Zsolt Kokrehel, and Dean Čizmar. "Screw Connection in Reinforced Concrete Column Joints of Prefabricated Structures." Solid State Phenomena 259 (May 2017): 249–54. http://dx.doi.org/10.4028/www.scientific.net/ssp.259.249.
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Classic connection between prefabricated reinforced concrete columns on a foundation slab using the concrete plinth base can sometimes be very problematic, especially in limited construction conditions and / or foundation on sandy terrain where the groundwater is very close to the ground surface. By applying the screw connection between a prefabricated reinforced concrete column and the foundation structure using anchor bolts and column shoes, the overall height of the foundation is successfully reduced. The established connection between prefabricated reinforced concrete column and the foundation can immediately sustain the design force after assembly and it is considered to be a rigid connection that acts as an equivalent conventional connection with concrete plinth base, without any other additional support and welding. The successful implementation is possible with underground levels of structures where the inverted concrete plinth bases are implemented - the indentation in the foundation slab for the connection of prefabricated columns with base plate is avoided.Application of the screw connection also enables the design of the continuation of the column at higher altitude (column to column) or connection of the upper part the element with the monolithic structure. Screw connection is particularly suitable for use in seismic areas because the performed tests showed very good ductility of the connections under cyclic load.
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Ali, A., Z. Soomro, S. Iqbal, N. Bhatti, and A. F. Abro. "Prediction of Corner Columns’ Load Capacity Using Composite Material Analogy." Engineering, Technology & Applied Science Research 8, no. 2 (April 19, 2018): 2745–49. http://dx.doi.org/10.48084/etasr.1879.
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There are numerous reasons for which concrete has become the most widely used construction material in buildings, one of them being its availability in different types, such as fiber-reinforced, lightweight, high strength, conventional and self-compacting concrete. This advantage is specially realized in high-rise building construction, where common construction practice is to use concretes of different types or strength classes in slabs and columns. Columns in such structures are generally made from concrete which is higher in compressive strength than the one used in floors or slabs. This raises issue of selection of concrete strength that should be used for estimating column capacity. Current paper tries to address this issue by testing nine (09) sandwich column specimens under axial loading. The floor concrete portion of the sandwich column was made of normal strength concrete, whereas column portions from comparatively higher strength concrete. Test results show that aspect ratio (h/b) influences the effective concrete strength of such columns. A previously adopted methodology of composite material analogy with some modifications has been found to predict well the capacity of columns where variation in floor and concrete strength is significant.
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Singh, H., and N. Cooke. "Ductile behaviour of reinforced masonry columns." Bulletin of the New Zealand Society for Earthquake Engineering 27, no. 2 (June 30, 1994): 83–95. http://dx.doi.org/10.5459/bnzsee.27.2.83-95.
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This paper presents the results of an experimental investigation into the strength and level of ductile performance of two reinforced concrete masonry columns and one reinforced clay brick column by Singh [1993]. The results show that strength of reinforced concrete and clay masonry can be predicted by using full cross-section dimensions. Columns constructed from concrete masonry behave in a ductile manner but clay masonry columns behave in a very limited ductile manner.
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Guan, Jun Feng, and Juan Wang. "Calculation of Shear Capacity of Continuous Compound Spiral Hoop Reinforced Concrete Column." Applied Mechanics and Materials 238 (November 2012): 240–43. http://dx.doi.org/10.4028/www.scientific.net/amm.238.240.
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High-ductility stirrups, which yield strength standard value is great than 1100MPa, are usually employed as a horizontal reinforcing steel bar of continuous compound spiral hoop reinforced concrete column to improve the anti-seismic performance of the short column. In this paper, a method is proposed to calculate the shear capacity of the continuous compound spiral hoop reinforced concrete column by regression analysis on the existing test data. Furthermore, the engineering application of the proposed method was illustrated in a specific case. This study provides supports for engineering projects of continuous compound spiral hoop reinforced concrete columns.
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Liu, Xiaoxian, Jianzhong Li, Hing-Ho Tsang, and John Wilson. "Enhancing seismic performance of unbonded prestressed concrete bridge column using superelastic shape memory alloy." Journal of Intelligent Material Systems and Structures 29, no. 15 (July 5, 2018): 3082–96. http://dx.doi.org/10.1177/1045389x18783074.
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In this article, an application of superelastic shape memory alloy strands for improving the seismic performance of unbonded prestressed reinforced concrete bridge column is proposed. In the reinforced concrete column with unbonded prestressing steel-shape memory alloy strands, superelastic shape memory alloy strands are put in series with unbonded steel strands, and the loading plateau of shape memory alloy is exploited to limit the increase in the axial load of column under an earthquake. Quasi-static analysis and seismic analysis were conducted to compare the seismic performance of conventional reinforced concrete column, reinforced concrete column with unbonded prestressing steel strands, and the proposed reinforced concrete column with unbonded prestressing steel-shape memory alloy strands. Result shows that reinforced concrete column with unbonded prestressing steel-shape memory alloy strands has larger ultimate displacement capacity than reinforced concrete column with unbonded prestressing steel strands in the quasi-static analysis. In the seismic analysis, reinforced concrete column with unbonded prestressing steel-shape memory alloy strands suffers from smaller earthquake residual displacement than reinforced concrete column and reinforced concrete column with unbonded prestressing steel strands. Furthermore, parametric analysis was carried out to investigate the effects of unbonded steel strand ratio, prestressing force ratio, bonded longitudinal reinforcement ratio, and maximum tensile force ratio (area of shape memory alloy strands) on the ultimate displacement and quasi-static residual displacement of reinforced concrete column with unbonded prestressing steel-shape memory alloy strands. Results show that increasing the prestressing force ratio and the maximum tensile force ratio within certain ranges can improve the self-centering capability of column. Increasing the area of bonded longitudinal reinforcement and unbonded steel strand ratio results in larger residual displacement.
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Omar, M. Y. M., R. B. Gomes, and A. P. A. Reis. "Experimental analysis of reinforced concrete columns strengthened with Self-Compacting concrete." Revista IBRACON de Estruturas e Materiais 3, no. 3 (September 2010): 271–83. http://dx.doi.org/10.1590/s1983-41952010000300002.
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This paper presents the results of reinforced concrete columns strengthened by addition of a self-compacting concrete overlay at the compressed and at the tensioned face of the member, with and without addition of longitudinal steel bars. Eight columns were submit- ted to loading with an initial eccentricity of 60 mm . These columns had 120 mm x 250 mm of rectangular cross section, 2000 mm in length and four longitudinal reinforcement steel bars with 10 mm in diameter. Reference columns P1 and P2 were tested to failure without any type of rehabilitation. Columns P3 to P8 were loaded to a predefined load (close to the initial yield point of tension reinforce- ment), then unloaded and strengthened for a subsequent test until failure. Results showed that the method of rehabilitation used was effective, increasing the loading capacity of the strengthened pieces by 2 to 5 times the ultimate load of the reference column.