The Experts below are selected from a list of 28455 Experts worldwide ranked by ideXlab platform
Zhao Jun - One of the best experts on this subject based on the ideXlab platform.
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Seismic behavior of reinforced Concrete Core walls under biaxial cyclic lateral loading
Journal of Building Structures, 2012Co-Authors: Zhao JunAbstract:In order to study the seismic behavior of reinforced Concrete Core wall under multi-dimensional loading,two reinforced Concrete Core wall models were built and tested to failure.One wall model was under uniaxial cyclic lateral loading and the other was under biaxial cyclic lateral loading.This paper presents the results,including failure mode,hysteretic behavior,load-carrying capacity,ductility,energy dissipation ability.It can be seen that the biaxial cyclic lateral loading has important effect on the seismic behavior of reinforced Concrete Core wall.Under biaxial cyclic lateral loading,stiffness and load-carrying capacity of the specimen are decreased and the ductility performance is reduced markedly.
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Finite Element Modeling and Parameter Analysis of the Concrete Core Wall
Journal of Disaster Prevention and Mitigation Engineering, 2010Co-Authors: Zhao JunAbstract:Finite element(FE) analysis of the reinforced Concrete Core wall under lateral loading is performed in this paper.The FE model,using the software ABAQUS,is proposed to carry out the nonlinear analysis and is verified by comparing the computational results with the corresponding experimental ones obtained from laboratory tests of large-scale specimens.On this basis,a series of reinforced Concrete Core walls with different axial load ratios,aspect ratios and wall thicknesses are simulated and analyzed under lateral loading.The results show the effects of these parameters on the behavior of reinforced Concrete Core walls.With increase of the axial load ratio,the failure mode of Core walls changes from tension failure mode towards compression one,and the lateral loading capacity of Core walls,increases at first,and then decreases,with their ductility getting worse.With increase of the aspect ratio,the failure mode of Core walls changes from the shear failure to the flexural failure with the improvement of ductility,while the base shear force decreases.Failure of the specimen with thin wall arises from the cross-section buckling instability, while the failure of specimens with thick wall is controlled by flexural capacity at bottom of wall piers,and with increase of the wall thickness,both bearing capacity and deformation ability of the Core walls significantly increase and energy dissipation ability improve with the failure region extending upward from the bottom.
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Experimental Study on Seismic Behavior of Reinforced Concrete Core Walls With Coupling Beams of Different Stiffness
Journal of Beijing University of Technology, 2010Co-Authors: Zhao JunAbstract:In order to further study the seismic behavior of reinforced Concrete Core wall and factors influence,two reinforced Concrete Core wall models with large height-width ratio are built and tested under the combined action of constant axial load and reversed cyclic lateral load. Failure mode,hysteretic behavior,load-carrying capacity,ductility,energy dissipation ability,shear lag effect of the stiffness of coupling beam on each Core wall was investigated. This result indicate that the final overall bending damage occurres at the bottom of each model and that the stiffness of coupling beam have important effects on the seismic behavior of reinforced Concrete Core wall. With the span-depth ratio of coupling beam dropping from 1. 7 to 0. 9,the stiffness and load-carrying capacity of the specimen has risen markedly,but the ductility performance drops significantly.
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Seismic Behavior of Reinforced Concrete Core Wall Under Different Axial Load Ratio
Journal of Beijing University of Technology, 2009Co-Authors: Zhao JunAbstract:In order to further study the seismic behavior of reinforced Concrete Core wall and factors influencing,two reinforced Concrete Core wall models with large height-width ratio were built and tested to failure under the combined action of constant axial load and reversed cyclic lateral load.The axial compression ratio on each Core wall was different.This paper presents the results,including failure mode,hysteretic behavior,load-carrying capacity,ductility,energy dissipation ability,shear lag effect.The final overall bending damage occurred at the bottom of each model.With the axial compression ratio increasing from 0.2 to 0.5,stiffness and load-carrying capacity of the specimen had risen markedly,but the ductility performance dropped significantly.It can be seen from the analysis that the axial compression ratio having important effect on the seismic behavior of reinforced Concrete Core wall.
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Experimental study on seismic behavior of reinforced Concrete Core walls with various span-depth ratio of coupling beam
Journal of Building Structures, 2008Co-Authors: Zhao JunAbstract:In order to further study the seismic behavior of reinforced Concrete Core wall,two reinforced Concrete Core wall specimens were built and tested to failure under the combined action of constant axial load and reversed cyclic lateral load.The span-depth ratio of coupling beam on each Core wall was focused on.This paper presents the results,including failure mode,hysteretic behavior,load-carrying capacity,ductility,energy dissipation ability,shear lag effect.The final overall bending damage occurred at the bottom of each specimen.With the span-depth ratio of coupling beams dropping from 1.7 to 0.9,stiffness and load-carrying capacity of the specimen had risen markedly,but the ductility performance dropped significantly.It can be seen that the span-depth ratio of coupling beam has important effect on the seismic behavior of reinforced Concrete Core wall.
Shi Cheng - One of the best experts on this subject based on the ideXlab platform.
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seismic performance of hybrid columns of Concrete filled square steel tube with frp confined Concrete Core
Journal of Composites for Construction, 2018Co-Authors: Peng Feng, Shi ChengAbstract:AbstractAn experimental program that investigated the seismic performance of Concrete-filled square steel tube with fiber-reinforced polymer (FRP)–confined Concrete Core (FCCC) column (SCFC) was co...
Faning Dang - One of the best experts on this subject based on the ideXlab platform.
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Improvement Methods for Reduction of the High Stress of Ultra-High Asphalt Concrete Core Dams
Applied Sciences, 2019Co-Authors: Jun Gao, Faning Dang, Yi Xue, Jie RenAbstract:With the rapid development of asphalt Concrete Core rockfill dams (ACCRDs), the construction of ultra-high asphalt Concrete Core rockfill dams (UACCRDs) has been improved significantly. However, the security problems of asphalt Concrete Core (ACC) become very prominent with the increase of dam height. The shear failure control standard and tensile failure control standard of ACC are suggested. The mechanisms of ACC that generate high shear stress and high tensile stress are investigated. Based on the definition of stress level and the transmission mechanism of arch structures, the improvement methods that reduce the high shear stress and high tensile stress of ultra-high asphalt Concrete Core (UACC) are proposed and investigated. The results show that the stress level of ACC can be reduced significantly by the increase of the strength parameters of ACC (failure ratio, cohesion, and internal friction angle). The following value ranges of the failure ratio, cohesion, and internal friction angle of ACC for the suitable construction of UACCRDs are recommended: Rf ≥ 0.75, C ≥ 0.30 MPa, and φ ≥ 28.5° (h = 150 m), with the growth gradient adjusted by 5%, 15%, and 5%/25 m. The tensile stress and tensile stress area can be reduced obviously by the new type of dams (curved asphalt Concrete Core rockfill dams (CACCRDs)). The value ranges of the curvature of CACC (k ≥ 1.0 × 10−3) for the suitable construction of UACCRDs are recommended.
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Investigation for the key technologies of ultra-high asphalt Concrete Core rockfill dams
Soils and Foundations, 2019Co-Authors: Jun Gao, Faning DangAbstract:Abstract The mechanical characteristics of ultra-high asphalt Concrete Core rockfill dams (UACCRDs) at different periods is investigated via Rankine’s earth pressure theory, and a shear safety control standard for UACCRDs is proposed. The reasonable material parameters of the asphalt Concrete Core (ACC) and transition material that independently and comprehensively satisfy the shear safety control standard are back-calculated. The engineering measures that reduce the stress level (shear stress) of the ACC are given. Moreover, the engineering measures (straight asphalt Concrete Core rockfill dams (SACCRDs) are designed as curved asphalt Concrete Core rockfill dams (CACCRDs)) that reduce the tensile stress of the ACC are proposed. Based on the theory of the straight beam and curved beam on Winkler elastic foundation, the simplified mechanical models of straight asphalt Concrete Core (SACC) and curved asphalt Concrete Core (CACC) are established. The improvement effect of CACC that reduces tensile stress is also investigated. The results show that the following value ranges of the internal friction angle, cohesion of ACC and the internal friction angle of transition material for the suitable construction of UACCRDs are recommended: φa ≥ 30.5°, Ca ≥ 0.25 MPa and φt ≤ 43.5° (h = 200 m), with the growth gradient adjusted by 0.5%, 1.5% and −0.5%/25 m. The stress level of ACC can be obviously reduced by increasing the internal friction angle and cohesion of ACC, and reducing the internal friction angle of transition material. The simplified mechanical models of SACC and CACC can estimate the force and deformation characteristic of the ACC (SACC and CACC) well. The CACC can significantly reduce tensile stress to a level approximately 42.8% lower than that of SACC.
Saber Fallah-valukolaee - One of the best experts on this subject based on the ideXlab platform.
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Compressive performance of steel fiber-reinforced rubberized Concrete Core detached from heated CFST
Construction and Building Materials, 2020Co-Authors: Nematzadeh, Amirhossein Karimi, Saber Fallah-valukolaeeAbstract:Abstract In this study, the compressive behavior of Concrete Cores detached from the high-strength Concrete-filled steel tube (CFST) members reinforced with steel fibers and containing crumb tire rubber was investigated experimentally after exposure to elevated temperatures. The test variables included the diameter-to-thickness ratio of the steel tube, volume content of crumb rubber replacing natural sand, volume fraction of steel fibers, and temperature. After the exposure of the CFST specimens to the elevated temperatures and subsequently removing the steel tubes, the detached Concrete Core was subjected to the axial compression test, and the parameters of compressive strength, modulus of elasticity, strain at peak stress, and weight loss, stress-strain relationship together with the ultrasonic pulse velocity, visual appearance, and failure mode were evaluated. Using the experimental results, expressions were developed to predict the mechanical properties of the Concrete Core at elevated temperatures taking into account the steel tube wall thickness. The findings indicated that increasing the thickness of the steel tube had a greater damaging effect on the heated Concrete Core, while in the fiber-reinforced specimens, this damaging effect was lower. Moreover, the addition of crumb rubber to the Concrete mix as the natural sand replacement degraded the mechanical properties of the heated and unheated Concrete Core.
Jun Gao - One of the best experts on this subject based on the ideXlab platform.
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Improvement Methods for Reduction of the High Stress of Ultra-High Asphalt Concrete Core Dams
Applied Sciences, 2019Co-Authors: Jun Gao, Faning Dang, Yi Xue, Jie RenAbstract:With the rapid development of asphalt Concrete Core rockfill dams (ACCRDs), the construction of ultra-high asphalt Concrete Core rockfill dams (UACCRDs) has been improved significantly. However, the security problems of asphalt Concrete Core (ACC) become very prominent with the increase of dam height. The shear failure control standard and tensile failure control standard of ACC are suggested. The mechanisms of ACC that generate high shear stress and high tensile stress are investigated. Based on the definition of stress level and the transmission mechanism of arch structures, the improvement methods that reduce the high shear stress and high tensile stress of ultra-high asphalt Concrete Core (UACC) are proposed and investigated. The results show that the stress level of ACC can be reduced significantly by the increase of the strength parameters of ACC (failure ratio, cohesion, and internal friction angle). The following value ranges of the failure ratio, cohesion, and internal friction angle of ACC for the suitable construction of UACCRDs are recommended: Rf ≥ 0.75, C ≥ 0.30 MPa, and φ ≥ 28.5° (h = 150 m), with the growth gradient adjusted by 5%, 15%, and 5%/25 m. The tensile stress and tensile stress area can be reduced obviously by the new type of dams (curved asphalt Concrete Core rockfill dams (CACCRDs)). The value ranges of the curvature of CACC (k ≥ 1.0 × 10−3) for the suitable construction of UACCRDs are recommended.
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Investigation for the key technologies of ultra-high asphalt Concrete Core rockfill dams
Soils and Foundations, 2019Co-Authors: Jun Gao, Faning DangAbstract:Abstract The mechanical characteristics of ultra-high asphalt Concrete Core rockfill dams (UACCRDs) at different periods is investigated via Rankine’s earth pressure theory, and a shear safety control standard for UACCRDs is proposed. The reasonable material parameters of the asphalt Concrete Core (ACC) and transition material that independently and comprehensively satisfy the shear safety control standard are back-calculated. The engineering measures that reduce the stress level (shear stress) of the ACC are given. Moreover, the engineering measures (straight asphalt Concrete Core rockfill dams (SACCRDs) are designed as curved asphalt Concrete Core rockfill dams (CACCRDs)) that reduce the tensile stress of the ACC are proposed. Based on the theory of the straight beam and curved beam on Winkler elastic foundation, the simplified mechanical models of straight asphalt Concrete Core (SACC) and curved asphalt Concrete Core (CACC) are established. The improvement effect of CACC that reduces tensile stress is also investigated. The results show that the following value ranges of the internal friction angle, cohesion of ACC and the internal friction angle of transition material for the suitable construction of UACCRDs are recommended: φa ≥ 30.5°, Ca ≥ 0.25 MPa and φt ≤ 43.5° (h = 200 m), with the growth gradient adjusted by 0.5%, 1.5% and −0.5%/25 m. The stress level of ACC can be obviously reduced by increasing the internal friction angle and cohesion of ACC, and reducing the internal friction angle of transition material. The simplified mechanical models of SACC and CACC can estimate the force and deformation characteristic of the ACC (SACC and CACC) well. The CACC can significantly reduce tensile stress to a level approximately 42.8% lower than that of SACC.