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Seismic performance of steel reinforced ultra high-strength concrete composite frame joints 被引量:5
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作者 Yan Changwang Jia Jinqing 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2010年第3期439-448,共10页
To investigate the seismic performance of a composite frame comprised of steel reinforced ultra high-strength concrete (SRUHSC) columns and steel reinforced concrete (SRC) beams, six interior frame joint specimens... To investigate the seismic performance of a composite frame comprised of steel reinforced ultra high-strength concrete (SRUHSC) columns and steel reinforced concrete (SRC) beams, six interior frame joint specimens were designed and tested under low cyclically lateral load. The effects of the axial load ratio and volumetric stirrup ratio were studied on the characteristics of the frame joint performance including crack pattern, failure mode, ductility, energy dissipation capacity, strength degradation and rigidity degradation. It was found that all joint specimens behaved in a ductile manner with flexural-shear failure in the joint core region while plastic hinges appeared at the beam ends. The ductility and energy absorption capacity of joints increased as the axial load ratio decreased and the volumetric stirIup ratio increased. The displacement ductility coefficient and equivalent damping coefficient of the joints fell between the corresponding coefficients of the steel reinforced concrete (SRC) frame joint and RC frame joint. The axial load ratio and volumetric stirrup ratio have less influence on the strength degradation and more influence on the stiffness degradation. The stiffness of the joint degrades more significantly for a low volumetric stirrup ratio and high axial load ratio. The characteristics obtained from the SRUHSC composite frame joint specimens with better seismic performance may be a useful reference in future engineering applications. 展开更多
关键词 cyclical test axial load ratio volumetric stirrup ratio DUCTILITY strength degradation stiffness degradation steel reinforced ultra high strength concrete beam-column joint
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Seismic Performance of Steel Reinforced Ultra High-strength Concrete Columns 被引量:1
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作者 贾金青 《四川大学学报(工程科学版)》 EI CAS CSCD 北大核心 2009年第3期216-222,230,共8页
The seismic performance of steel reinforced ultra-high-strength concrete columns(SRSHC) with various shear-span ratios(λ) were studied through a series of experiments.The concrete compressive cube strength value of e... The seismic performance of steel reinforced ultra-high-strength concrete columns(SRSHC) with various shear-span ratios(λ) were studied through a series of experiments.The concrete compressive cube strength value of experimental specimens ranged from 92.9 MPa to 108.1 MPa.The main experimental variables affecting seismic performance of specimens were axial load ratio and stirrup reinforcement ratio.The columns(λ=2.75) subjected to low cyclic reversed lateral loads failed mainly in the flexural-shear mode failure and columns(λ≤2.0) subjected to low cyclic reversed lateral loads failed mainly in the shear mode failure.Shear force-displacement hysteretic curves and skeleton curves were drawn.Coefficient of the specimen displacement ductility was calculated.Experimental results indicate that ductility decreases with axial pressure ratio increasing,and increases with stirrup reinforcement ratio increasing.Limit values of axial pressure ratio and minimum stirrup reinforcement ratio of columns are proposed to satisfy definite ductility requirement.The suggested values provide a reference for engineering application and for the amendment of the current Chinese design code of steel reinforced concrete composite structures. 展开更多
关键词 建筑结构 建筑物 抗震设计 混凝土结构
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Experimental investigation of axially loaded steel fiber reinforced high strength concrete-filled steel tube columns 被引量:9
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作者 卢亦焱 李娜 +1 位作者 李杉 梁鸿骏 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第6期2287-2296,共10页
An experimental study on the compressive behavior of steel fiber reinforced concrete-filled steel tube columns is presented. Specimens were tested to investigate the effects of the concrete strength, the thickness of ... An experimental study on the compressive behavior of steel fiber reinforced concrete-filled steel tube columns is presented. Specimens were tested to investigate the effects of the concrete strength, the thickness of steel tube and the steel fiber volume fraction on the ultimate strength and the ductility. The experimental results indicate that the addition of steel fibers in concrete can significantly improve the ductility and the energy dissipation capacity of the concrete-filled steel tube columns and delay the local buckling of the steel tube, but has no obvious effect on the failure mode. It has also been found that the addition of steel fibers is a more effective method than using thicker steel tube in enhancing the ductility, and more advantageous in the case of higher strength concrete. An analytical model to estimate the load capacity is proposed for steel tube columns filled with both plain concrete and steel fiber reinforced concrete. The predicted results are in good agreement with the experimental ones obtained in this work and literatures. 展开更多
关键词 concrete-filled steel tube (CFST) zolumns steel fiber high strength concrete axial load DUCTILITY load capacity
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Charactersitics of Stress-strain Curve of High Strength Steel Fiber Reinforced Concrete under Uniaxial Tension 被引量:2
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作者 杨萌 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2006年第3期132-137,共6页
A whole of 110 specimens divided into 22 groups were tested with varying the volume fraction of steel fibers and the matrix strength of these specimens. The stress-strain behaviors of four types of steel fiber reinfo... A whole of 110 specimens divided into 22 groups were tested with varying the volume fraction of steel fibers and the matrix strength of these specimens. The stress-strain behaviors of four types of steel fiber reinforced concrete (SFRC) under uniaxial tension were studied experimentally. When the matrix strength and the fiber content increase, the tensile stress and tensile strain vary differently according to the fiber type. The mechanisms of reinforcing effect for different types of fiber were analyzed and the stress-strain curves of the specimens were plotted. Some experimental factors for stress or strain of SFRC were given. A tensile toughness modulus Re0.5 was introduced to evaluate the toughness characters of SFRC under uniaxial tension. Moreover, the formula of the tensile stress-strain curve of SFRC was regressed. The theoretical curve and the experimental ones fit well, which can be used for references in construction. 展开更多
关键词 steel fiber reinforced concrete high strength uniaxial tension soften characteristics stress-strain curve
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Evaluation of the Shear Strength of Perfobond Rib Connectors in Ultra High Performance Concrete 被引量:7
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作者 Jae Yoon Kang Jong Sup Park +1 位作者 Woo Tai Jung Moon Seoung Keum 《Engineering(科研)》 2014年第13期989-999,共11页
Since the previous strength prediction models for the perfobond rib connector were proposed based upon the results of push-out tests conducted on concretes with compressive strength below 50 MPa, push-out test is perf... Since the previous strength prediction models for the perfobond rib connector were proposed based upon the results of push-out tests conducted on concretes with compressive strength below 50 MPa, push-out test is performed on perfobond shear connectors applying ultra high performance concretes with compressive strength higher than 80 MPa to evaluate their shear resistance. The test variables are chosen to be the diameter and number of dowel holes and, the change in the shear strength of the perfobond rib connector is examined with respect to the strength of two types of UHPC: steel fiber-reinforced concrete with compressive strength of 180 MPa and concrete without steel fiber with compressive strength of 80 MPa. The test results reveal that higher concrete strength and larger number of holes increased the shear strength, and that higher increase rate in the shear strength was achieved by the dowel action. The comparison with the predictions obtained by the previous models shows that the experimental results are close to the values given by the model proposed by Oguejiofor and Hosain [1]. 展开更多
关键词 Perfobond RIB CONNECTOR Ultra high performance concrete Push-Out Test SHEAR strength
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Seismic Performance of High-Strength Short Concrete Column with High-Strength Stirrups Constraints 被引量:3
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作者 Hongyan Ding Yuan Liu +1 位作者 Chao Han Yaohua Guo 《Transactions of Tianjin University》 EI CAS 2017年第4期360-369,共10页
The seismic performance of four short concrete columns was investigated under low cycle and repeated loads, including the failure characteristics, hysteretic behavior, rigidity degeneracy and steel-bar stress. The inf... The seismic performance of four short concrete columns was investigated under low cycle and repeated loads, including the failure characteristics, hysteretic behavior, rigidity degeneracy and steel-bar stress. The influences of reinforcement strength, stirrup ratio and shear span ratio were also compared. Test results reveal that the restriction effect of stirrups can improve the peak stress, so the bearing capacity of specimen can be improved; for the high-strength short concrete column with high-strength stirrups, it was more reasonable to use ultimate displacement angle to reflect the ductility of the specimen, and the yield strength of high-strength stirrups should be devalued when calculating the stirrup characteristic value; the seismic performance of short column would be improved with the increase of volume–stirrup ratio and shear span ratio; the high-strength stirrups and high-strength longitudinal reinforcements did not yield when the load acting on the specimen reached the peak value, which brought adequate safety stock to these short columns. © 2017, Tianjin University and Springer-Verlag Berlin Heidelberg. 展开更多
关键词 Columns (structural) concrete construction concreteS HYSTERESIS Reinforced concrete reinforcement Seismic waves SEISMOLOGY Shear flow
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Structural Behavior of Continuous Prestressed Steel Fiber Reinforced High Strength Concrete Beam 被引量:2
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作者 刘海波 向天宇 赵人达 《Journal of Southwest Jiaotong University(English Edition)》 2008年第1期37-45,共9页
The flexural behaviors of continuous fully and partially prestressed steel fiber reinforced high strength concrete beams are studied by experiment and nonlinear finite element analysis. Three levels of partial prestre... The flexural behaviors of continuous fully and partially prestressed steel fiber reinforced high strength concrete beams are studied by experiment and nonlinear finite element analysis. Three levels of partial prestress ratio (PPR) are considered, and three pairs of two-span continuous beams with box sections varying in size are designed. The major parameters involved in the study include the PPR and the fiber location. It is concluded that the prestressed high strength concrete beam exhibits satisfactory ductility; the influences of steel fiber on the crack behaviors for partially prestressed beams are not as obvious as those for fully prestressed ones; steel fibers can improve the structural stiffness after cracking for fully prestressed high strength concrete beams; the moment redistribution from mid-span to intermediate support in the first stage should be mainly considered in practical design. 展开更多
关键词 high strength concrete steel fiber reinforced concrete Prestressed concrete Continuous beam
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Behavior of High Strength Concrete Filled Square Steel Tube Stub Columns with Inner CFRP Tube Under Biaxial Eccentric Compression 被引量:1
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作者 Zhijian Yang Guochang Li +1 位作者 Yan Lang Zengmei Qiu 《Computer Modeling in Engineering & Sciences》 SCIE EI 2021年第4期273-290,共18页
This paper studies the contribution of CFRP(carbon fiber-reinforced polymer)to the mechanical behavior of high strength concrete-filled square steel tube(HCFST)under biaxial eccentric compression.The new type of compo... This paper studies the contribution of CFRP(carbon fiber-reinforced polymer)to the mechanical behavior of high strength concrete-filled square steel tube(HCFST)under biaxial eccentric compression.The new type of composite member is composed of an inner CFRP tube and an outer steel tube with concrete filled in the two tubes.The finite element analysis was made by ABAQUS on the behavior of high strength concrete filled square steel tubular columns with inner CFRP circular tube subjected to bi-axial eccentric loading.The results obtained from the finite element analysis were verified with the experimental results.In addition,the load-deflection curves in the whole process were calculated and analyzed,which can be divided into three segments:Elastic phase,plastic phase,descending phase.Based on the load-deflection curves,the stresses analysis on the core concrete,CFRP tube and steel tube were conducted.The confinement effect of the CFRP tube improves the ductility of HCFST-CFRP stub column.CFRP ratio and eccentricity affect the ultimate bearing capacity of HCFST stub column.Finally,a calculation formula of ultimate bearing capacity was proposed in the paper. 展开更多
关键词 CFRP tube concrete-filled square steel tube high strength concrete bi-axial bending stub column
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A Study on the Bond Strength between High Performance Concrete and Reinforcing Bar 被引量:2
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作者 Eun Suk Choi Jung Woo Lee +1 位作者 Seong Jun Kim Jong Won Kwark 《Engineering(科研)》 2015年第7期373-378,共6页
As a preliminary study for the erection of floating structures using high performance concrete, this paper examines the bond characteristics between concrete and the reinforcing bar. Since the floating structure is co... As a preliminary study for the erection of floating structures using high performance concrete, this paper examines the bond characteristics between concrete and the reinforcing bar. Since the floating structure is constructed in aquatic environment, corrosion of the reinforcing steel is likely to develop more prematurely than in onshore structure in case of concrete cracking. A solution to this corrosion problem could use FRP rebar instead of steel reinforcement. To that goal, an experimental study is conducted on the concrete-FRP bond strength to verify if such FRP rebar develops performance comparable to the conventional steel rebar. A series of tests are performed considering the bond length of ordinary steel rebar and G-FRP rebar as test variable with respect to the strength of concrete, and the results are presented. 展开更多
关键词 FRP reinforcement high performance concrete BOND strength concrete strength BOND LENGTH
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FAILURE MODE AND CONSTITUTIVE MODEL OF PLAIN HIGH-STRENGTH HIGH-PERFORMANCE CONCRETE UNDER BIAXIAL COMPRESSION AFTER EXPOSURE TO HIGH TEMPERATURES 被引量:2
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作者 Zhenjun He Yupu Song 《Acta Mechanica Solida Sinica》 SCIE EI 2008年第2期149-159,共11页
An orthotropic constitutive relationship with temperature parameters for plain highstrength high-performance concrete (HSHPC) under biaxial compression is developed. It is based on the experiments performed for char... An orthotropic constitutive relationship with temperature parameters for plain highstrength high-performance concrete (HSHPC) under biaxial compression is developed. It is based on the experiments performed for characterizing the strength and deformation behavior at two strength levels of HSHPC at 7 different stress ratios including a=σs : σ3=0.00:-1,-0.20:-1,-0.30 : -1,-0.40:-1,-0.50:-1,-0.75:-1,-1.00:-1, after the exposure to normal and high temperatures of 20, 200, 300, 400, 500 and 600℃, and using a large static-dynamic true triaxial machine. The biaxial tests were performed on 100 mm×100 mm×100 mm cubic specimens, and friction-reducing pads were used consisting of three layers of plastic membrane with glycerine in-between for the compressive loading plane. Based on the experimental results, failure modes of HSHPC specimens were described. The principal static compressive strengths, strains at the peak stress and stress-strain curves were measured; and the influence of the temperature and stress ratios on them was also analyzed. The experimental results showed that the uniaxial compressive strength of plain HSHPC after exposure to high temperatures does not decrease dramatically with the increase of temperature. The ratio of the biaxial to its uniaxial compressive strength depends on the stress ratios and brittleness-stiffness of HSHPC after exposure to different temperature levels. Comparison of the stress-strain results obtained from the theoretical model and the experimental data indicates good agreement. 展开更多
关键词 high-strength high-performance concrete (HSHPC) high temperatures uniaxial biaxial compressive strength failure criterion stress-strain relationship
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Strength Regularity and Failure Criterion of High-Strength High-Performance Concrete under Multiaxial Compression 被引量:1
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作者 何振军 宋玉普 《Journal of Southwest Jiaotong University(English Edition)》 2008年第2期144-149,共6页
Multiaxial compression tests were performed on 100 mm×100 mm×100 mm high-strength high-performance concrete (HSI-IPC) cubes and normal strength concrete (NSC) cubes. The failure modes of specimens were p... Multiaxial compression tests were performed on 100 mm×100 mm×100 mm high-strength high-performance concrete (HSI-IPC) cubes and normal strength concrete (NSC) cubes. The failure modes of specimens were presented, the static compressive strengths in principal directions were measured, the influence of the stress ratios was analyzed. The experimental results show that the ultimate strengths for HSHPC and NSC under multiaxial compression are greater than the uniaxial compressive strengths at all stress ratios, and the multiaxial strength is dependent on the brittleness and stiffness of concrete, the stress state and the stress ratios. In addition, the Kupfer-Gersfle and Ottosen's failure criteria for plain HSHPC and NSC under multiaxial compressive loading were modified. 展开更多
关键词 high-strength high-performance concrete (HSHPC) Normal strength concrete (NSC) Stress ratio Multiaxial corn- pressive slxength Failure criterion
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STUDY ON OPTIMIZATION OF HIGH PERFORMANCE CONCRETE ADMIXTURES 被引量:7
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作者 刘俊龙 麻海燕 +2 位作者 李强 陈树东 张云清 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2011年第2期206-210,共5页
Influences of admixtures on the workability and strength of high performance concrete (HPC) are in- vestigated. The types of investigated admixtures include naphthalene series high range water reducing agent, polyca... Influences of admixtures on the workability and strength of high performance concrete (HPC) are in- vestigated. The types of investigated admixtures include naphthalene series high range water reducing agent, polycarboxlic series high range water reduce agent and sodium sulfate hardening accelerating agent. Two kinds of curing condition, namely steam curing condition and standard curing condition, are adopted. The result shows that HPC, added with polycarboxlic series of high performance water reducer, has high workability and strength, while sodium sulfate accelerating agent causes poor workability and low strength. Thus for vapor-cured HPC and its formulations, naphthalene series high range water reducing agent with less sodium sulfate should be given pri- ority. Therefore, the differences of curing conditions should be considered when selecting HPC admixtures. 展开更多
关键词 high performance concrete high performance water reducer hardening accelerating agent SLUMP compressive strength
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Properties of High Strength Steel Fiber Reinforced Concrete under Compression
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作者 钱春香 IndubhushanPatnaikuni 《Journal of Southeast University(English Edition)》 EI CAS 1996年第2期130-136,共7页
This paper mainly discusses the properties of high strength steel fiber reinforced concrete under compression. Steel fibers with volume content of 1% do not display significant effect on the strain at peak stress and... This paper mainly discusses the properties of high strength steel fiber reinforced concrete under compression. Steel fibers with volume content of 1% do not display significant effect on the strain at peak stress and the area of the ascending portion of 展开更多
关键词 steel FIBER REINFORCED concrete high strength stress strain PROPERTIES
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Flexural Behaviour of High-Strength Steel Fiber-Reinforced Concrete Beams
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作者 钱春香 IndubhushanPatnaikuni 《Journal of Southeast University(English Edition)》 EI CAS 1996年第2期137-144,共8页
This paper presents the research results of twelve high strength concrete beams reinforced with steel fibers and bars. Fiber type I and II reduce the deflection by more than 25% and increase the ultimate load by abou... This paper presents the research results of twelve high strength concrete beams reinforced with steel fibers and bars. Fiber type I and II reduce the deflection by more than 25% and increase the ultimate load by about 10% compared to high strength concr 展开更多
关键词 high strength concrete beam steel FIBER deflection crack DUCTILITY
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Seismic Behavior of Steel Reinforced Ultra High Strength Concrete Column and Reinforced Concrete Beam Connection
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作者 闫长旺 贾金青 张菊 《Transactions of Tianjin University》 EI CAS 2010年第4期309-316,共8页
To investigate the seismic behavior of connections composed of steel reinforced ultra high strength concrete (SRUHSC) column and reinforced concrete (RC) beam, six interior strong-column-weak-beam connection specimens... To investigate the seismic behavior of connections composed of steel reinforced ultra high strength concrete (SRUHSC) column and reinforced concrete (RC) beam, six interior strong-column-weak-beam connection specimens were tested subjected to reversal cyclic load. Effects of applied axial load ratio and volumetric stirrup ratio on ductility, energy dissipation capacity, strength degradation and rigidity degradation were discussed. It was found that all connection specimens failed in bending in a ductile manner with a beam plastic hinge. The ductility and energy dissipation capacity increased with the decrease of applied axial load ratio or increase of volumetric stirrup ratio. The displacement ductility coefficient and equivalent damping coefficient lay between those of steel reinforced ordinary concrete connection and those of reinforced concrete connection. The applied axial load ratio and volumetric stirrup ratio had less influence on the strength degradation and more influence on the stiffness degradation. The stiffness degraded sharply with the decrease of volumetric stirrup ratio or increase of applied axial load ratio. The experimental results indicate that SRUHSC column and RC beam connection exhibited better seismic performance and can provide reference for engineering application. 展开更多
关键词 seismic performance steel reinforced ultra high strength concrete CONNECTION applied axial load ratio volumetric stirrup ratio
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Comparative Study on Test Performance of Two Kinds of High Modulus Asphalt Concrete for the Steel Bridge Deck
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作者 Jianlin Yuan Junjie Yang 《Journal of Architectural Research and Development》 2021年第2期21-24,共4页
Along with the popularization and application of the steel bridge in China,due to the high modulus of asphalt concrete with good waterproof,anti-fatigue,anti-aging and good performance,asphalt concrete with high modul... Along with the popularization and application of the steel bridge in China,due to the high modulus of asphalt concrete with good waterproof,anti-fatigue,anti-aging and good performance,asphalt concrete with high modulus was widely used in steel bridge deck pavement,the test and comparative study of high modulus asphalt concrete were carried out based on two types of common high modulus asphalt concrete which include the casting type asphalt concrete and epoxy resin modified asphalt concrete,aims to further explore the performance features of the steel bridge deck with high modulus asphalt concrete,and provide help on the application of this asphalt concrete on the steel bridge deck. 展开更多
关键词 steel bridge deck high modulus Asphalt concrete Test performance
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Experimental study on the seismic behavior of high strength concrete fi lled double-tube columns 被引量:13
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作者 Qian Jiaru Li Ningbo +1 位作者 Ji Xiaodong Zhao Zuozhou 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2014年第1期47-57,共11页
To study the seismic behavior of high strength concrete fi lled double-tube(CFDT) columns,each consisting of an external square steel tube and an internal circular steel tube,quasi-static tests on eight CFDT column sp... To study the seismic behavior of high strength concrete fi lled double-tube(CFDT) columns,each consisting of an external square steel tube and an internal circular steel tube,quasi-static tests on eight CFDT column specimens were conducted.The test variables included the width-to-thickness ratio(β1) and the area ratio(β2) of the square steel tube,the wall thickness of the circular steel tube,and the axial force(or the axial force ratio) applied to the CFDT columns.The test results indicate that for CFDT columns with a square steel tube with β1 of 50.1 and 24.5,local buckling of the specimen was found at a drift ratio of 1/150 and 1/50,respectively.The lateral force-displacement hysteretic loops of all specimens were plump and stable.Reducing the width-to-thickness ratio of the square steel tube,increasing its area ratio,or increasing the wall thickness of the internal circular steel tube,led to an increased fl exural strength and deformation capacity of the specimens.Increasing the design value of the axial force ratio from 0.8 to 1.0 may increase the fl exural strength of the specimens,while it may also decrease the ultimate deformation capacity of the specimen with β1 of 50.1. 展开更多
关键词 high strength concrete fi lled double-tube(CFDT)column seismic behavior area ratio of the square steel tube width-to-thickness ratio of the square steel tube axial force ratio quasi-static test
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Mechanism of improving ductility of high strength concrete T-section beam confined by CFRP sheet subjected to flexural loading 被引量:4
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作者 王苏岩 王泽源 《Journal of Central South University》 SCIE EI CAS 2013年第1期246-255,共10页
For the purpose of inventing a new seismic retrofitting method for the reinforced high strength concrete (HSC) T-section beam using carbon fiber reinforced polymer (CFRP) sheet, three series, a total of twelve T-s... For the purpose of inventing a new seismic retrofitting method for the reinforced high strength concrete (HSC) T-section beam using carbon fiber reinforced polymer (CFRP) sheet, three series, a total of twelve T-section beams with nine specimens confined by CFRP sheet in the plastic zone and three control beams were conducted up to failure under four-point bending test. The effectiveness of confining CFRP sheet on improving the flexural ductility of tmstrengthened T-section beams was studied. The parameters such as the width and the thickness of CFRP sheet and the type of T-section were analyzed. The experimental results show that ductility and rotation capacity of plastic hinge can be improved by the confinement of CFRP sheet, and the ductility indices increase with the increment of width and thickness of CFRP sheet. A plastic rotation model considering the width of CFRP sheet and the effect of flange of T-section beam is proposed on the basis of the model of BAKER, and the test results show a good agreement with the perdicted results. The relevant construction suggestions for seismic retrofitting design of beam-slabs system in cast-in-place framework structure are presented. 展开更多
关键词 high strength concrete fiber reinforced polymer T-section BEAM DUCTILITY plastic hinge
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Characterization of Surface Hardness and Microstructure of High Performance Concrete 被引量:3
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作者 杨永敢 张云升 SHE Wei 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2018年第1期124-132,共9页
The relationship between compressive strength obtained by universal testing machine and rebound value obtained by the hammer of high performance concrete was systematically investigated at the macro level. And a model... The relationship between compressive strength obtained by universal testing machine and rebound value obtained by the hammer of high performance concrete was systematically investigated at the macro level. And a model of high performance concrete strength curve was established from them. At the micro level, the microstructure, hydration products and pore structure of concrete surface were analyzed by scanning electron microscopy(SEM), comprehensive thermal analysis(TG-DSC) and mercury intrusion porosimetry(MIP), respectively. The effect of carbonation on surface strength was also investigated. The results showed that the concrete surface hardness layer grew rapidly at early stage and then stabilized at last with ongoing curing age; the rebound value and compressive strength of concrete with slag were higher than those of concrete with the same content of fly ash. In addition, the strength curve obtained by the least square method can satisfy the local standard requirements with an average relative error of 8.9% and a relative standard deviation of 11.3%. When the carbonation depth was 6 mm, the compressive strength calculated by national uniform strength curve was 25 PMa higher than that by high performance concrete. 展开更多
关键词 high performance concrete rebound test parameter analysis strength curve
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Influence of shrinkage-reducing admixture on drying shrinkage and mechanical properties of high-performance concrete 被引量:5
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作者 Nguyen Quangphu Jiang Linhua +2 位作者 Liu Jiaping Tian Qian Do Tienquan 《Water Science and Engineering》 EI CAS 2008年第4期67-74,共8页
High-performance concrete (HPC) has specific performance advantages over conventional concrete in strength and durability. HPC mixtures are usually produced with water/binder mass ratios (mW/mB) in the range of 0.... High-performance concrete (HPC) has specific performance advantages over conventional concrete in strength and durability. HPC mixtures are usually produced with water/binder mass ratios (mW/mB) in the range of 0.2-0.4, so volume changes of concrete as a result of drying, chemical reactions, and temperature change cannot be avoided. For these reasons, shrinkage and cracking are frequent phenomena. It is necessary to add some types of admixture for reduction of shrinkage and cracking of HPC. This study used a shrinkage-reducing admixture (SRA) for that purpose. Concrete was prepared with two different mW/mB (0.22 and 0.40) and four different mass fractions of SRA to binder (w(SRA) = 0%, 1%, 2%, and 4%). The mineral admixtures used for concrete mixes were: 25% fly ash (FA) and 25% slag by mass of binder for the mixture with mW/mB = 0.40, and 15% silica fume (SF) and 25% FA for the mixture with mW/mB = 0.22. Tests were conducted on 24 prismatic specimens, and shrinkage strains were measured through 120 days of drying. Compressive strength, splitting strength, and static modulus of elasticity were also determined. The results show that the SRA effectively reduces some mechanical properties of HPC. The reductions in compressive strength, splitting tensile strength, and elastic modulus of the concrete were 7%-24%, 9%-19%, and 5%-12%, respectively, after 90 days, compared to concrete mixtures without SRA. SRA can also help reduce drying shrinkage of concrete. The shrinkage strains of HPC with SRA were only as high as 41% of the average free shrinkage of concrete without SRA after 120 days of drying. 展开更多
关键词 high-performance concrete shrinkage-reducing admixture compressive strength elastic modulus splitting tensile strength drying shrinkage
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