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Effect of Lightweight Aggregates Incorporation on the Mechanical Properties and Shrinkage Compensation of a Cement-Ground Granulated Blast Furnace Slag-Phosphogypsum Ternary System

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Fluid Dynamics & Materials Processing 2024年第8期20卷 1773-1784页

作者： Yu Wang Mengyang Ma Yong Long Qingxiang Zhao Zhifei Cheng State Key Laboratory of bridge Intelligent and Green Construction China Railway Major Bridge Engineering Group Co.Ltd.Wuhan430034China China Railway bridge Science Research Institute. Ltd.Wuhan430034China

Shrinkage-induced cracking is a common issue in concrete structures,where the formation of cracks not only affects the aesthetic appearance of concrete but also potentially reduces its durability and *** this study,the effect of ceramsite sand addition on the properties of a ternary system of cement-ground granulated blast furnace slag(GGBFS)-phosphogypsum(PG)is *** particular,the fluidity,rheology,hydration heat,compressive strength,autogenous shrinkage,and drying shrinkage of the considered mortar specimens are *** results indicate that an increase in PG content leads to a decrease in fluidity,higher viscosity,lower exothermic peak,and lower compressive ***,the shrinkage of the mortar specimens is effectively *** incorporation of internal curing water from ceramsite sand improves fluidity,decreases both yield stress and viscosity,enhances the degree of hydration,and induces mortar ***,the inferior mechanical properties of the ceramsite sand generally produce a decrease in the compressive strength.

关键词： Phosphogypsum ceramsite sand internal curing mechanical property shrinkage

Research on an innovative structure of an open-ribbed steel-ultra-high performance concrete composite bridge deck

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Frontiers of Structural and Civil engineering 2024年第5期18卷 716-730页

作者： Xudong SHAO Xuan SUN Deqiang ZOU Junhui CAO Chuanqi YANG School of Civil engineering Hunan UniversityKey Laboratory for Wind and Bridge Engineering of Hunan ProvinceChangsha 410082China China Construction Fifth engineering Division Co. Ltd.Changsha 410004China

To completely solve the problem of fatigue cracking issue of orthotropic steel bridge decks(OSDs),the authors proposed a steel–ultra-high performance concrete(UHPC)lightweight composite deck(LWCD)with closed ribs in *** on the successful application of that LWCD,an adaptation incorporating an innovative composite deck structure,i.e.,the hot-rolled section steel–UHPC composite deck with open ribs(SSD)is proposed in this paper,aiming to simplify the fabrication process as well as to reduce the cost of *** on a long-span cable-stayed bridge,a design scheme is proposed and is compared with the conventional OSD ***,a finite element(FE)calculation is conducted to reflect both the global and local behavior of the SSD scheme,and it is found that the peaked stresses in the SSD components are less than the corresponding allowable values.A static test is performed for an SSD strip specimen to understand the anti-cracking behavior of the UHPC layer under negative bending *** static test results indicate that the UHPC layer exhibited a satisfactory tensile toughness,the UHPC tensile strength obtained from the test is 1.8 times the calculated stress by the FE model of the real *** addition,the fatigue stresses of typical fatigue-prone details in the SSD are calculated and evaluated,and the influences of key design parameters on the fatigue performance of the SSD are *** to the fatigue results,the peaked stress ranges for all of the 10 fatigue-prone details are within the corresponding constant amplitude fatigue *** a fatigue test is carried out for another SSD strip specimen to explore the fatigue behavior of the fillet weld between the longitudinal and transverse *** specimen failed at the fillet weld after equivalent 47.5 million cycles of loading under the design fatigue stress range,indicating that the fatigue performance of the SSD could meet the fatigue design *** calculations and experim

关键词： steel-ultra-high performance concrete composite deck open rib strip model test static and fatigue performance orthotropic steel deck

Constitutive Behavior of the Interface between UHPC and Steel Plate without Shear Connector:From Experimental to Numerical Study

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Computer Modeling in engineering & Sciences 2024年第8期140卷 1863-1888页

作者： Zihan Wang Boshan Zhang Hui Wang Qing Ai Xingchun Huang School of Naval Architecture Ocean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China Department of bridge engineering Tongji UniversityShanghai200092China

The application of ultra-high performance concrete(UHPC)as a covering layer for steel bridge decks has gained widespread *** employing a connection without a shear connector between the steel plate and UHPC,namely,the sandblasted interface and the epoxy adhesive with sprinkled basalt aggregate interface,the installation cannot only be simplified but also the stress concentration resulting from the welded shear connectors can be *** study develops constitutive models for these two interfaces without shear connectors,based on the interfacial pull-off and push-out *** validation,three-point bending tests on the steel-UHPC composite plates are *** results indicated that the proposed bilinear traction-separation model for the sandblasted interface and the trapezoidal traction-separation model for the epoxy adhesive with sprinkled basalt aggregate interface can generally calibrate the interfacial ***,the utilization of the experimentally determined pure shear strength underestimates the load-carrying capacity of the composite plates in the case of three-point bending *** recalling the Mohr-Coulomb criterion,this underestimation is attributed to the enhancement of the interface shear strength by the presence of normal stress.

关键词： Cohesive zone model interfacial behavior finite element simulation UHPC steel plate

Development and Application of a Power Law Constitutive Model for Eddy Current Dampers

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Computer Modeling in engineering & Sciences 2024年第3期138卷 2403-2419页

作者： Longteng Liang Zhouquan Feng Hongyi Zhang Zhengqing Chen Changzhao Qian School of Civil engineering and Architecture Xiamen University of TechnologyXiamen361024China Hunan Provincial Key Laboratory ofWind and bridge engineering Hunan UniversityChangsha410082China Fujian Provincial Key Laboratory ofWind Disaster and engineering Xiamen University of TechnologyXiamen361024China State Key Laboratory of bridge engineering Safety and Resilience Hunan UniversityChangsha410082China

Eddy current dampers (ECDs) have emerged as highly desirable solutions for vibration control due to theirexceptional damping performance and durability. However, the existing constitutive models present challenges tothe widespread implementation of ECD technology, and there is limited availability of finite element analysis (FEA)software capable of accurately modeling the behavior of ECDs. This study addresses these issues by developing anewconstitutivemodel that is both easily understandable and user-friendly for FEAsoftware. By utilizing numericalresults obtained from electromagnetic FEA, a novel power law constitutive model is proposed to capture thenonlinear behavior of ECDs. The effectiveness of the power law constitutive model is validated throughmechanicalproperty tests and numerical seismic analysis. Furthermore, a detailed description of the application process ofthe power law constitutive model in ANSYS FEA software is provided. To facilitate the preliminary design ofECDs, an analytical derivation of energy dissipation and parameter optimization for ECDs under harmonicmotionis performed. The results demonstrate that the power law constitutive model serves as a viable alternative forconducting dynamic analysis using FEA and optimizing parameters for ECDs.

关键词： Eddy current damper constitutive model finite element analysis vibration control power law constitutive model

Numerical Study on the Aerodynamic and Fluid−Structure Interaction of An NREL-5MW Wind Turbine

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China Ocean engineering 2024年第3期38卷 363-378页

作者： ZHAO Mi YU Wan-li WANG Pi-guang QU Yang DU Xiu-li Key Laboratory of Urban Security and Disaster engineering of Ministry of Education Beijing University of TechnologyBeijing 100124China State Key Laboratory of bridge engineering Safety and Resilience Beijing University of TechnologyBeijing 100124China

A 5-MW wind turbine has been modeled and analyzed for fluid-structure interaction and aerodynamic *** this study, a full-scale model of a 5-MW wind turbine is first developed based on a computational fluid dynamics(CFD) approach, in which the unsteady, noncompressible Reynolds Averaged Navier-Stokes(RANS) method is used. The main focus of the study is to analyze the tower shadow effect on the aerodynamic performance of the wind turbine under different inlet flow conditions. Subsequently, the finite element model is established by considering fluid/structure interactions to study the structural stress, displacement, strain distributions and flow field information of the structure under the uniform wind speed. Finally, the fluid-structure interaction model is established by considering turbulent wind and the tower shadow effect. The variation rules of the dynamic response of the one-way and two-way fluid-structure interaction(FSI) models under different wind speeds are analyzed, and the numerical calculation results are compared with those of the centralized mass model. The results show that the tower shadow effect and structural deformation are the main factors affecting the aerodynamic load fluctuation of the wind turbine, which in turn affects the aerodynamic performance and structural stability of the blades. The structural dynamic response of the coupled model shows significant similarity, while the structural displacement response of the former exhibits less fluctuation compared with the conventional centralized mass model. The one-way fluid-structure interaction(FSI)model shows a higher frequency of stress-strain and displacement oscillations on the blade compared with the two-way FSI model.

关键词： computational fluid dynamics methods(CFD) tower shadow effect aerodynamic performance fluidstructure interaction space flow field

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Study of Axial Force and Deformation of Double-System Composite Guideway Considering Slip and Uplift Effects

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Journal of Traffic and Transportation engineering(English Edition) 2024年

作者： Zhengwei Bai Eryu Zhu Wenchao Cai Honghe Jian Jiacheng Li dept.of bridge， Beijing Jiaotong University

This study fills the gap in the theoretical research of the interface deformation of the Double-System Composite Guideway (DSCG) in multi-system monorail transportation. By integrating the vertical lifting theory of the combined interface with the three-way deformation theory， this paper established a methodology for the interface analysis of the DSCG. Subsequently， a finite element analysis model of the DSCG was developed using a modified parameter model， enabling the study and summary of the deformation laws of the interface under different vehicle loads. The results show that the modified finite element model reduces the axial force and deformation by approximately 10%. Under vehicle loading， the transverse deformation of the combined interface accounts for 65.26% of the transverse deformation at the bottom of the concrete guideway， the vertical deformation accounts for 27.1%， and the longitudinal deformation accounts for 74.55%. Under the influence of a level 10 vehicle load， the deformation of the combined interface in three directions is uniformly distributed， indicating that the connectors remain in the elastic stage. The conclusions of this paper not only lay a foundation for the research of the DSCG guideway but also promote the development of a multi-standard monorail transit system.

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Eigenfrequency analysis of bridges using a smartphone and a novel low-cost accelerometer prototype

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Frontiers of Structural and Civil engineering 2024年第2期18卷 202-215页

作者： Seyedmilad KOMARIZADEHASL Ye XIA Mahyad KOMARY Fidel LOZANO Department of Civil and Environment engineering Universitat Politècnica de CatalunyaBarcelona 08034Spain Department of bridge engineering Tongji UniversityShanghai 200092China Department of Civil engineering Universidad de Castilla-La ManchaCiudad Real 13071Spain

Researchers are paying increasing attention to the development of low-cost and microcontroller-based accelerometers,in order to make structural health monitoring feasible for conventional bridges with limited monitoring *** with the low-cost sensor development,the use of the embedded accelerometers of smartphones for eigenfrequency analysis of bridges is becoming popular in the civil engineering *** paper,for the first time in the literature,studies these two promising technologies by comparing the noise density and eigenfrequency analysis of a self-developed,validated and calibrated low-cost Internet of things based accelerometer LARA(low cost adaptable reliable accelerometer)with those of a state of the art smartphone(iPhone XR).The eigenfrequency analysis of a footbridge in San Sebastian,Spain,showed that the embedded accelerometer of the iPhone XR can measure the natural frequencies of the under study bridge.

关键词： smartphone modal analysis eigenfrequency analysis low-cost accelerometers Arduino Raspberry Internet of things

Experiment and constitutive modelling of creep deformation in the frozen silt-concrete interface

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Journal of Mountain Science 2024年第9期21卷 3172-3185页

作者： HE Fei LIU Qingquan LEI Wanyu WANG Xu MAO Erqing LI Sheng CHEN Hangjie School of Civil engineering Lanzhou Jiaotong UniversityLanzhou 730070China Key Laboratory of Road&bridge and Underground engineering of Gansu Province Lanzhou 730070China

To ensure the long-term safety and stability of bridge pile foundations in permafrost regions,it is necessary to investigate the rheological effects on the pile tip and pile side bearing *** creep characteristics of the pile-frozen soil interface are critical for determining the long-term stability of permafrost pile *** study utilized a self-developed large stress-controlled shear apparatus to investigate the shear creep characteristics of the frozen silt-concrete interface,and examined the influence of freezing temperatures(−1,−2,and−5°C),contact surface roughness(0,0.60,0.75,and 1.15 mm),normal stress(50,100,and 150 kPa),and shear stress on the creep characteristics of the contact *** incorporating the contact surface’s creep behavior and development trends,we established a creep constitutive model for the frozen silt-concrete interface based on the Nishihara model,introducing nonlinear elements and a damage *** results revealed significant creep effects on the frozen silt-concrete interface under constant load,with creep displacement at approximately 2-15 times the instantaneous displacement and a failure creep displacement ranging from 6 to 8 *** different experimental conditions,the creep characteristics of the frozen silt-concrete interface varied.A larger roughness,lower freezing temperatures,and higher normal stresses resulted in a longer sample attenuation creep time,a lower steady-state creep rate,higher long-term creep strength,and stronger creep *** upon the Nishihara model,we considered the influence of shear stress and time on the viscoelastic viscosity coefficient and introduced a damage factor to the *** improved model effectively described the entire creep process of the frozen silt-concrete *** results provide theoretical support for the interaction between pile and soil in permafrost regions.

关键词： Creep characteristics Contact surface Frozen silt Constitutive model Freezing temperature

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Analytical Solution and Simplified Formula for Added Mass of Horizontal and Vertical Motions of Truncated Cylinders Under Earthquake Action

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China Ocean engineering 2024年第1期38卷 54-67页

作者： WANG Pi-guang LYU Si-yu QU Yang ZHAO Mi DU Xiu-li State Key Laboratory of bridge engineering Safety and Resilience Beijing University of TechnologyBeijing 100124China Key Laboratory of Urban Security and Disaster engineering of Ministry of Education Beijing University of Tech-nologyBeijing 100124China

This paper investigates the hydrodynamic characteristics of floating truncated cylinders undergoing horizontal and vertical motions due to earthquake excitations in the finite water *** governing equation of the hydrodynamic pressure acting on the cylinder is derived based on the radiation theory with the inviscid and incompressible *** governing equation is solved by using the method of separating variables and analytical solutions are obtained by assigning reasonable boundary *** analytical result is validated by a numerical model using the exact artificial boundary simulation of the infinite *** main variation and distribution characteristics of the hydrodynamic pressure acting on the side and bottom of the cylinder are analyzed for different combinations of wide-height and immersion *** added mass coefficient of the cylinder is calculated by integrating the hydrodynamic pressure and simplified formulas are proposed for engineering *** calculation results show that the simplified formulas are in good agreement with the analytical solutions.

关键词： earthquake hydrodynamic pressure truncated cylinder added mass simplified formula

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