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Effects of Manufactured-sand on Dry Shrinkage and Crccp of High-strength Concrete 被引量:4
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作者 ZHOU Mingkai WANG Jiliang ZHU Lide HE Tusheng 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2008年第2期249-253,共5页
The influences of natural sand, manufactured-sand (MS) and stone-dust (SD) in the manufactured-sand on workability, compressive strength, elastic modulus, drying shrinkage and creep properties of high-strength con... The influences of natural sand, manufactured-sand (MS) and stone-dust (SD) in the manufactured-sand on workability, compressive strength, elastic modulus, drying shrinkage and creep properties of high-strength concrete (HSC) were tested and compared. The results show that the reasonable content (7%-10.5%) of SD in MS will not deteriorate the workability of MS-HSC. It could even improve the workability. Moreover, the compressive strength increases gradually with the increasing SD content,and the MS- HSC with low SD content (smaller than 7%) has the elastic modulus which approaches that of the natural sand HSC, but the elastic modulus reduces when the SD content is high. The influence of the SD content on drying shrinkage performance of MS-HSC is closely related to the hydration age. The shrinkage rate of MS-HSC in the former 7 d age is higher than that of the natural sand HSC, but the difference of the shrinkage rate in the late age is not marked. Meanwhile the shrinkage rate reduces as the fly ash is added; the specific creep and creep coefficient of MS-HSC with 7% SD are close to those of the natural sand HSC. 展开更多
关键词 manufactured-sand natural sand high-strength concrete dry shrinkage CREEP
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Nonlinear fi nite element analysis of high-strength concrete columns and experimental verification 被引量:1
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作者 吕西林 陈绍琳 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2008年第1期77-89,共13页
This paper describes a nonlinear finite element (FE) analysis of high strength concrete (HSC) columns, and verifies the results through laboratory experiments. First, a cyclically lateral loading test on nine cant... This paper describes a nonlinear finite element (FE) analysis of high strength concrete (HSC) columns, and verifies the results through laboratory experiments. First, a cyclically lateral loading test on nine cantilever column specimens of HSC is described and a numerical simulation is presented to verify the adopted FE models. Next, based on the FE model for specimen No.6, numerical simulations for 70 cases, in which different concrete strengths, stirrup ratios and axial load ratios are considered, are presented to explore the effect of these parameters on the behavior of the HSC columns, and to check the rationality of requirements for these columns specified in the China Code for Seismic Design of Buildings (GB 50011- 2001). In addition, three cases with different stirrup strengths are analyzed to investigate their effect on the behavior of HSC columns. Finally, based on the numerical results some conclusions are presented. 展开更多
关键词 high-strength concrete column DIANA BOND-SLIP balanced axial load ratio stirrup ratio
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Uplift behavior and load transfer mechanism of prestressed high-strength concrete piles 被引量:1
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作者 赖颖 金国芳 《Journal of Central South University》 SCIE EI CAS 2010年第1期136-141,共6页
Prestressed high-strength-concrete (PHC) tube-shaped pile is one of the recently used foundations for soft soil. The research on uplift resistance of PHC pile is helpful to the design of pile foundations. A field-scal... Prestressed high-strength-concrete (PHC) tube-shaped pile is one of the recently used foundations for soft soil. The research on uplift resistance of PHC pile is helpful to the design of pile foundations. A field-scale test program was conducted to study the uplift behavior and load transfer mechanism of PHC piles in soft soil. The pullout load tests were divided into two groups with different diameters, and there were three piles in each group. A detailed discussion of the axial load transfer and pile skin resistance distribution was also included. It is found from the tests that the uplift capacity increases with increasing the diameter of pile. When the diameter of piles increases from 500 to 600 mm, the uplift load is increased by 51.2%. According to the load-displacement (Q-S) curves, all the piles do not reach the ultimate state at the maximum load. The experimental results show that the piles still have uplift bearing capacity. 展开更多
关键词 prestresed high-strength concrete piles full-scale test uplift capacity load transfer mechanism
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CT Image-based Analysis on the Defect of Polypropylene Fiber Reinforced High-Strength Concrete at High Temperatures 被引量:2
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作者 杜红秀 JIANG Yu +1 位作者 LIU Gaili YAN Ruizhen 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2017年第4期898-903,共6页
With the application of X-ray computed tomography(CT) technology of C80 high-strength concrete with polypropylene fiber at elevated temperatures, the microscopic damage evolution process observation and image buildi... With the application of X-ray computed tomography(CT) technology of C80 high-strength concrete with polypropylene fiber at elevated temperatures, the microscopic damage evolution process observation and image building could be obtained, based on the statistics theory and numerical analysis of the combination of concrete internal defects extension and evolution regularity of microscopic structure. The expermental results show that the defect rate has changed at different temperatures and can determine the concrete degradation threshold temperatures. Also, data analysis can help to establish the evolution equation between the defect rate and the effect of temperature damage, and identify that the addition of polypropylene fibers in the high strength concrete at high temperature can improve cracking resistance. 展开更多
关键词 high-strength concrete polypropylene fiber high temperature X-ray computed tomography(CT) technology defect rate
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Pseudo-dynamic test and numerical simulation of high-strength concrete frame structure reinforced with high-strength rebars
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作者 Chen Xin Yan Shi Ji Baojian 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2011年第2期303-311,共9页
This paper describes an investigation of a high-strength concrete frame reinforced with high-strength rebars that was tested in the structure engineering laboratory at Shenyang Jianzhu University. The frame specimen w... This paper describes an investigation of a high-strength concrete frame reinforced with high-strength rebars that was tested in the structure engineering laboratory at Shenyang Jianzhu University. The frame specimen was pseudo- dynamically loaded to indicate three earthquake ground motions of different hazard levels, after which the test specimen was subjected to a pseudo-static loading. This paper focuses on the design, construction and experiment of the test frame and validation of the simulation models. Research shows that a high-strength concrete frame reinforced with high-strength rebars is more efficient and economical than a traditional reinforced concrete frame structure. In addition to the economies achieved by effective use of materials, research shows that the frame can provide enough strength to exceed conventional reinforced concrete frames and provide acceptable ductility. The test study provides evidence to validate the performance of a high- strength concrete frame designed according to current seismic code provisions. Based on previous test research, a nonlinear FEM analysis is completcd by using OpenSees software, The dynamic responses of the frame structure are numerically analyzed, The results of the numerical simulation show that the model can calculate the seismic responses of the frame by OpenSees. At the same time, the test provides additional opportunities to validate the performance of the simulation models. 展开更多
关键词 high-strength concrete pseudo dynamic test seismic response analysis frame structure finite elementmethod OPENSEES
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Seismic behavior of multiple reinforcement,high-strength concrete columns:experimental and theoretical analysis
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作者 Xing Guohua Wang Haonan Osman E.Ozbulut 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2022年第2期359-375,共17页
This study investigates the seismic performance of multiple reinforcement,high-strength concrete(MRHSC)columns that are characterized by multiple transverse and longitudinal reinforcements in core areas.Eight MRHSC co... This study investigates the seismic performance of multiple reinforcement,high-strength concrete(MRHSC)columns that are characterized by multiple transverse and longitudinal reinforcements in core areas.Eight MRHSC columns were designed and subjected to a low cycle,reversed loading test.The response,including the failure modes,hysteretic behavior,lateral bearing capacity,and displacement ductility,was analyzed.The effects of the axial compression ratio,stirrup form,and stirrup spacing of the central reinforcement configuration on the seismic performance of the columns were studied.Furthermore,an analytical model was developed to predict the backbone force-displacement curves of the MRHSC columns.The test results showed that these columns experienced two failure modes:shear failure and flexure-shear failure.As the axial compression ratio increased,the bearing capacity increased significantly,whereas the deformation capacity and ductility decreased.A decrease in the spacing of central transverse reinforcements improved the ductility and delayed the degradation of load-bearing capacity.The proposed analytical model can accurately predict the lateral force and deformations of MRHSC columns. 展开更多
关键词 high-strength concrete multiple reinforcement columns seismic behavior theoretical model cyclic loading test
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Experimental investigation on strength and deformation of plain high-strength concrete under multiaxial stress state
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作者 何振军 宋玉普 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2009年第5期616-622,共7页
To investigate the strength and deformation behavior of plain high-strength concrete (HSC) under muhiaxial stress states, a large static-dynamic true triaxial machine was employed, and muhiaxial tests were performed... To investigate the strength and deformation behavior of plain high-strength concrete (HSC) under muhiaxial stress states, a large static-dynamic true triaxial machine was employed, and muhiaxial tests were performed on 100 mm × 100 mm × 100 mm cubes concrete specimens. Friction-reducing pads were three-layer plastic membranes with glycerine in-between for the compressive loading plane. The tensile loading plane of concrete samples was processed by attrition machine, and then the samples were glued up with the loading plate with structural glue. Failure modes of specimens were described. The principal static compressive strengths, strains at the peak stress and stress-strain curves were measured, and the influence of stress ratios on them was analyzed as well. Experimental results show that the ratio of the compressive strength σ3f over the uniaxial compressive strengthfo depends on brittleness-stiffness of concrete besides stress state and stress ratios. The formula of Kupfer-Gerstle' s and Ottosen' s failure criterion for plain HSC under biaxial compression and muhiaxial stress state is proposed respectively. 展开更多
关键词 high-strength concrete HSC stress ratios muhiaxial strength mechanical properties stress- strain relationship
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Elasto-plastic Analysis of High-strength Concrete Shear Wall with Boundary Columns Using Fiber Model
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作者 Xiaolong Tong Yangjing Ou +2 位作者 Sixi Xiao Jianliang Wu Fumin Chen 《Journal of Construction Research》 2020年第1期21-28,共8页
In this study,an experimental study and numerical calculations using fiber model were conducted for four high-strength concrete shear walls with boundary columns under low cyclic load.The boundary column and shear wal... In this study,an experimental study and numerical calculations using fiber model were conducted for four high-strength concrete shear walls with boundary columns under low cyclic load.The boundary column and shear wall were divided into fiber elements,and PERFORM-3D finite element analysis software was used to carry out push-over analysis on the test specimens.The results show that the finite element analysis results were in good agreement with the experimental results.The proposed analysis method could perform elasto-plastic analysis on the high-strength concrete shear wall with boundary columns without distinguishing the categories of frame column and shear wall.The seismic performance of high-strength concrete shear wall with boundary columns was analyzed using the following parameters:axis compression ratio,height to width ratio,ratio of vertical reinforcement,and ratio of longitudinal reinforcement in the boundary column.The results show that the increase in the axial compression ratio causes the bearing capacity of the shear wall to increase at first and then to decrease and causes the ductility to decrease.The increase in the height to width ratio causes the bearing capacity of the shear wall to decrease and its ductility to increase.The ratio of vertical reinforcement was found to have little effect on the bearing capacity and ductility.The increase in the ratio of longitudinal reinforcement in boundary column resulted in a significant increase in the bearing capacity and caused the ductility to decrease at first and then to slowly increase. 展开更多
关键词 Boundary columns high-strength concrete Fiber model Shear wall
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Experimental and Numerical Analysis of High-Strength Concrete Beams Including Steel Fibers and Large-Particle Recycled Coarse Aggregates 被引量:3
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作者 Chunyang Liu Yangyang Wu +1 位作者 Yingqi Gao Zhenyun Tang 《Fluid Dynamics & Materials Processing》 EI 2021年第5期947-958,共12页
In order to study the performances of high-strength concrete beams including steel fibers and large-particle recycled aggregates,four different beams have been designed,tested experimentally and simulated numerically.... In order to study the performances of high-strength concrete beams including steel fibers and large-particle recycled aggregates,four different beams have been designed,tested experimentally and simulated numerically.As varying parameters,the replacement rates of recycled coarse aggregates and CFRP(carbon fiber reinforced polymer)sheets have been considered.The failure mode of these beams,related load deflection curves,stirrup strain and shear capacity have been determined through monotonic loading tests.The simulations have been conducted using the ABAQUS finite element software.The results show that the shear failure mode of recycled concrete beams is similar to that of ordinary concrete beams.The shear carrying capacity of high-strength concrete beams including steel fibers and large-particle recycled coarse aggregates grows with an increase in the replacement rate of recycled coarse aggregates.Reinforcement with CFRP sheets can significantly improve the beam’s shear carrying capacity and overall resistance to deformation. 展开更多
关键词 high-strength recycled concrete beam steel fiber large-particle recycled aggregates pre-damage reinforcement numerical simulation carrying capacity calculation
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Residual Mechanical Properties and Explosive Spalling Behavior of Ultra-High-Strength Concrete Exposed to High Temperature 被引量:2
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作者 Gaifei Peng Juan Yang 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2017年第4期62-70,共9页
In order to explore the characteristics of ultra-high-strength concrete exposed to high temperature,residual mechanical properties and explosive spalling behavior of ultra-high-strength concrete( UHSC) and high streng... In order to explore the characteristics of ultra-high-strength concrete exposed to high temperature,residual mechanical properties and explosive spalling behavior of ultra-high-strength concrete( UHSC) and high strength concrete( HSC) exposed to high temperatures ranging from 20 ℃ to 800 ℃ were determined. The microstructure of the specimens after exposure to elevated temperature was analyzed by means of scanning electron microscope( SEM) and mercury intrusion porosimetry( MIP). The residual compressive strengths of UHSC and HSC were first increased and then decreased as temperature increased. After exposure to 800 ℃,the compressive strengths of UHSC and HSC were 24. 2 % and 22. 3 % of their original strengths at 20 ℃,respectively. The residual splitting tensile strengths of both UHSC and HSC were consistently decreased with the temperature increasing and were approximately 20% of their original strengths after 800 ℃. However,the residual fracture energies of both concretes tended to ascend even at 600 ℃. The explosive spalling of UHSC was more serious than that of HSC. Moisture content of the specimens governs the explosive spalling of both concretes with a positive correlations,and it is more pronounced in UHSC. These results suggest that UHSC suffers a substantial loss in load-bearing capacity and is highly prone to explosive spalling due to high temperature. The changes in compressive strength are due to the changes in the density and the pore structure of concrete. The probability and severity of explosive spalling of UHSC are much higher than those of HSC due to the higher pore volume in HSC. 展开更多
关键词 ultra-high-strength concrete high strength concrete RESIDUAL mechanical properties EXPLOSIVE SPALLING
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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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Mechanical properties of high-strength concrete subjected to high temperature by stressed test 被引量:10
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作者 Gyu-Yong KIM Young-Sun KIM Tae-Gyu LEE 《中国有色金属学会会刊:英文版》 CSCD 2009年第B09期128-133,共6页
Recently, the effects of high temperature on compressive strength and elastic modulus of high strength concrete were experimentally investigated. The present study is aimed to study the effect of elevated temperatures... Recently, the effects of high temperature on compressive strength and elastic modulus of high strength concrete were experimentally investigated. The present study is aimed to study the effect of elevated temperatures ranging from 20 ℃ to 700 ℃ on the material mechanical properties of high-strength concrete of 40, 60 and 80 MPa grade. During the strength test, the specimens are subjected to a 25% of ultimate compressive strength at room temperature and sustained during heating, and when the target temperature is reached, the specimens are loaded to failure. The tests were conducted at various temperatures (20-700 ℃) for concretes made with W/B ratios of 46%, 32% and 25%, respectively. The results show that the relative values of compressive strength and elastic modulus decrease with increasing compressive strength grade of specimen. 展开更多
关键词 高强混凝土 高温作用 力学性能 测试 抗压强度 温度升高 弹性模量 强度试验
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An Improved Technique of Calculating Deflections of Flexural Reinforced Concrete Elements Made of Conventional and High-Strength Concrete
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作者 Gennadiy Murashkin Vasiliy Murashkin Denis Panfilov 《Journal of Civil Engineering and Architecture》 2013年第2期125-131,共7页
The paper presents an improved technique of calculating total deflections of flexural reinforced concrete elements that takes discrete crack formation into account. The technique is based on determining the curvature ... The paper presents an improved technique of calculating total deflections of flexural reinforced concrete elements that takes discrete crack formation into account. The technique is based on determining the curvature of the cross section of reinforced concrete elements with cracks and fissures in the area between cracks. The curvature of the element is calculated using a non-linear function of the deformation of concrete under compression. Approximating dependency of concrete resistance on compression developed by one of the authors is presented. An algorithm of finding the curvature and formulas for calculating curvature and deflection are provided. The function of the curvature distribution along the length of a flexible element is proposed by the authors. The paper also presents the results of the author's experimental research. The characteristics of samples tested are described. The experimental research results of deflections of fiexural reinforced concrete elements made of conventional and high-strength concretes are presented. Comparison of the values calculated using the technique with those obtained from the experimental research as well as those calculated according to existing regulations in Russia, USA and Europe is drawn. 展开更多
关键词 DEFLECTION concrete tension diagram flexural elements.
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Thermo-Mechanical Modeling of High-Strength Concrete Column Subjected to Moderate Case Heating Scenario in a Fire
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作者 Tarek Eltalhi Awad S.Bodalal +1 位作者 Farag M.Shuaeib Vail Karakale 《Journal of Mechanical Materials and Mechanics Research》 2022年第2期32-52,共21页
This paper presents a numerically developed computer model to simulate the thermal behavior and evaluate the mechanical performance of a fixed ends centrically loaded High Strength Concrete Column(HSCC),subjected to M... This paper presents a numerically developed computer model to simulate the thermal behavior and evaluate the mechanical performance of a fixed ends centrically loaded High Strength Concrete Column(HSCC),subjected to Moderate Case Heating Scenario(MCHS),in a hydrocarbon fire.The temperature distribution within the mid-height cross-sectional area of the column was obtained to determine the thermal and mechanical responses as a function of temperature.The governing two-dimensional transient heat transfer partial differential equation(PDE),was converted into a set of or­dinary algebraic equations,subsequently,integrated numerically by using the explicit finite difference method,(FDM).A computer program,Visual Basic for Applications(VBA),was then developed to solve the set of or­dinary algebraic equations by implementing the boundary as well as initial conditions.The predictions of the model were validated against experimen­tal data from previous studies.The general behavior of the model as well as the effect of the key model parameters were investigated at length in the review.Finally,the reduction in the column’s compression strength and the modulus of elasticity was estimated using correlations from existing litera­ture.And the HSCC failure load under fire conditions was predicted using the Rankine formula.The results showed that the model predictions of the temperature distribution within the concrete column are in good agreement with the experimental data.Furthermore,the increase in temperature of the reinforced concrete column,(RCC),due to fire resulted in a significant reduction in the column compression strength and considerably accelerates the column fire failure load. 展开更多
关键词 High strength concrete FIRE Thermal behavior Model validation
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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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Slender reinforced concrete shear walls with high-strength concrete boundary elements
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作者 Mohammad SYED Pinar OKUMUS 《Frontiers of Structural and Civil Engineering》 SCIE EI CSCD 2023年第1期138-151,共14页
Reinforced concrete structural walls are commonly used for resisting lateral forces in buildings. Owing to the advancements in the field of concrete materials over the past few decades, concrete mixes of high compress... Reinforced concrete structural walls are commonly used for resisting lateral forces in buildings. Owing to the advancements in the field of concrete materials over the past few decades, concrete mixes of high compressive strength, commonly referred to as high-strength concrete (HSC), have been developed. In this study, the effects of strategic placement of HSC on the performance of slender walls were examined. The finite-element model of a conventional normal-strength concrete (NSC) prototype wall was validated using test data available in extant studies. HSC was incorporated in the boundary elements of the wall to compare its performance with that of the conventional wall at different axial loads. Potential reductions in the reinforcement area and size of the boundary elements were investigated. The HSC wall exhibited improved strength and stiffness, and thereby, allowed reduction in the longitudinal reinforcement area and size of the boundary elements for the same strength of the conventional wall. Cold joints resulting from dissimilar concrete pours in the web and boundary elements of the HSC wall were modeled and their impact on behavior of the wall was examined. 展开更多
关键词 slender walls high-strength concrete rectangular and barbell-shaped walls cold joints
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Intelligent Small Sample Defect Detection of Concrete Surface Using Novel Deep Learning Integrating Improved YOLOv5 被引量:2
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作者 Yongming Han Lei Wang +1 位作者 Youqing Wang Zhiqiang Geng 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第2期545-547,共3页
Dear Editor,This letter presents an intelligent small sample defect detection of concrete surface using novel deep learning integrating the improved YOLOv5 based on the Wasserstein GAN(WGAN)enhancement algorithm.The p... Dear Editor,This letter presents an intelligent small sample defect detection of concrete surface using novel deep learning integrating the improved YOLOv5 based on the Wasserstein GAN(WGAN)enhancement algorithm.The proposed method is capable of producing top-notch data sets to address the issues of insufficient samples and substandard quality. 展开更多
关键词 concrete integrating ALGORITHM
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Utilization of Basalt Saw Mud as a Spherical Porous Functional Aggregate for the Preparation of Ordinary Structure Concrete 被引量:1
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作者 周永祥 关青锋 +2 位作者 LENG Faguang WANG Jing LI Tianjun 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第2期364-375,共12页
To promote the production and application of artificial aggregates,save natural sand resources and protect the ecological environment,we evaluated the feasibility of using spherical porous functional aggregates(SPFAs)... To promote the production and application of artificial aggregates,save natural sand resources and protect the ecological environment,we evaluated the feasibility of using spherical porous functional aggregates(SPFAs) formed by basalt saw mud under autoclave curing in ordinary structural concrete.In our work,two types of prewetted functional aggregates were taken as replacements for natural aggregates with different volume substitution rates(0%,5%,10%,15%,20%,25%,and 30%) in the preparation of ordinary structural concrete with water-to-binder ratios(W/B) of 0.48 and 0.33.The effects of the functional aggregate properties and content,W/B,and curing age on the fluidity,density,mechanical properties and autogenous shrinkage of ordinary concrete were analyzed.The experimental results showed that the density of concrete declined at a rate of not more than 5%,and the 28 d compressive strength could reach 31.0-68.2 MPa.Low W/B,long curing age and high-quality functional aggregates were conducive to enhancing the mechanical properties of SPFAs concrete.Through the rolling effects,SPFAs can optimize the particle gradation of aggregate systems and improve the fluidity of concrete,and the water stored inside SPFAs provides an internal curing effect,which prolongs the cement hydration process and considerably reduces the autogenous shrinkage of concrete.SPFAs exhibits high strength and high density,as well as being more cost-effective and ecological,and is expected to be widely employed in ordinary structural concrete. 展开更多
关键词 lightweight concrete civil concrete building basalt saw mud fly ash internal curing environmentally friendly
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High-speed penetration of ogive-nose projectiles into thick concrete targets:Tests and a projectile nose evolution model 被引量:1
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作者 Xu Li Yan Liu +4 位作者 Junbo Yan Zhenqing Shi Hongfu Wang Yingliang Xu Fenglei Huang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第2期553-571,共19页
The majority of the projectiles used in the hypersonic penetration study are solid flat-nosed cylindrical projectiles with a diameter of less than 20 mm.This study aims to fill the gap in the experimental and analytic... The majority of the projectiles used in the hypersonic penetration study are solid flat-nosed cylindrical projectiles with a diameter of less than 20 mm.This study aims to fill the gap in the experimental and analytical study of the evolution of the nose shape of larger hollow projectiles under hypersonic penetration.In the hypersonic penetration test,eight ogive-nose AerMet100 steel projectiles with a diameter of 40 mm were launched to hit concrete targets with impact velocities that ranged from 1351 to 1877 m/s.Severe erosion of the projectiles was observed during high-speed penetration of heterogeneous targets,and apparent localized mushrooming occurred in the front nose of recovered projectiles.By examining the damage to projectiles,a linear relationship was found between the relative length reduction rate and the initial kinetic energy of projectiles in different penetration tests.Furthermore,microscopic analysis revealed the forming mechanism of the localized mushrooming phenomenon for eroding penetration,i.e.,material spall erosion abrasion mechanism,material flow and redistribution abrasion mechanism and localized radial upsetting deformation mechanism.Finally,a model of highspeed penetration that included erosion was established on the basis of a model of the evolution of the projectile nose that considers radial upsetting;the model was validated by test data from the literature and the present study.Depending upon the impact velocity,v0,the projectile nose may behave as undistorted,radially distorted or hemispherical.Due to the effects of abrasion of the projectile and enhancement of radial upsetting on the duration and amplitude of the secondary rising segment in the pulse shape of projectile deceleration,the predicted DOP had an upper limit. 展开更多
关键词 High-speed penetration concrete target EROSION Projectile nose evolution model
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Numerical parametric study on the influence of location and inclination of large-scale asperities on the shear strength of concreterock interfaces of small buttress dams 被引量:1
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作者 Dipen Bista Adrian Ulfberg +3 位作者 Leif Lia Jaime Gonzalez-Libreros Fredrik Johansson Gabriel Sas 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第10期4319-4329,共11页
When assessing the sliding stability of a concrete dam,the influence of large-scale asperities in the sliding plane is often ignored due to limitations of the analytical rigid body assessment methods provided by curre... When assessing the sliding stability of a concrete dam,the influence of large-scale asperities in the sliding plane is often ignored due to limitations of the analytical rigid body assessment methods provided by current dam assessment guidelines.However,these asperities can potentially improve the load capacity of a concrete dam in terms of sliding stability.Although their influence in a sliding plane has been thoroughly studied for direct shear,their influence under eccentric loading,as in the case of dams,is unknown.This paper presents the results of a parametric study that used finite element analysis(FEA)to investigate the influence of large-scale asperities on the load capacity of small buttress dams.By varying the inclination and location of an asperity located in the concrete-rock interface along with the strength of the rock foundation material,transitions between different failure modes and correlations between the load capacity and the varied parameters were observed.The results indicated that the inclination of the asperity had a significant impact on the failure mode.When the inclinationwas 30and greater,interlocking occurred between the dam and foundation and the governing failure modes were either rupture of the dam body or asperity.When the asperity inclination was significant enough to provide interlocking,the load capacity of the dam was impacted by the strength of the rock in the foundation through influencing the load capacity of the asperity.The location of the asperity along the concrete-rock interface did not affect the failure mode,except for when the asperity was located at the toe of the dam,but had an influence on the load capacity when the failure occurred by rupture of the buttress or by sliding.By accounting for a single large-scale asperity in the concrete-rock interface of the analysed dam,a horizontal load capacity increase of 30%e160%was obtained,depending on the inclination and location of the asperity and the strength of the foundation material. 展开更多
关键词 concrete dam Buttress dam SLIDING Shear strength concrete-rock interface Asperity inclination Asperity location
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