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Experiment and calculation on seismic behavior of RC composite core walls with concealed steel truss

Wanlin CAO , Weihua CHANG , Changjun ZHAO , Jianwei ZHANG ,

《结构与土木工程前沿(英文)》 2009年 第3卷 第3期   页码 255-261 doi: 10.1007/s11709-009-0043-0

摘要: To improve the seismic performance of reinforced concrete core walls, reinforced concrete composite core walls with concealed steel truss were proposed and systemically investigated. Two 1/6 scale core wall specimens, including a normal reinforced concrete core wall and a reinforced concrete composite core wall with concealed steel truss, were designed. The experimental study on seismic performance under cyclic loading was carried out. The load-carrying capacity, stiffness, ductility, hysteretic behavior and energy dissipation of the core walls were discussed. The test results showed that the seismic performance of core walls is improved greatly by the concealed steel truss. The calculated results were found to agree well with the actual measured ones.

关键词: reinforced concrete     steel truss     core walls     seismic performance    

Slender reinforced concrete shear walls with high-strength concrete boundary elements

《结构与土木工程前沿(英文)》 2023年 第17卷 第1期   页码 138-151 doi: 10.1007/s11709-022-0897-y

摘要: 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.

关键词: slender walls     high-strength concrete     rectangular and barbell-shaped walls     cold joints    

Behaviour of self-centring shear walls——A state of the art review

《结构与土木工程前沿(英文)》 2023年 第17卷 第1期   页码 53-77 doi: 10.1007/s11709-022-0850-0

摘要: The application of unbonded post-tensioning (PT) in structural walls has led to the development of advanced self-centring (rocking) shear wall systems that has significant advantages, including accelerated construction due to the incorporation of prefabricated elements and segmental construction for different materials (e.g., concrete, masonry, and timber), reduced residual drifts, and little damage upon extreme seismic and wind loads. Concrete, masonry, and timber are often used for the construction of unbonded PT structural wall systems. Despite extensive research since the 1980s, there are no well-established design guidelines available on the shear wall configuration with the required energy dissipation system, joint’s locations and acceptance criteria for shear sliding, confinement, seismic performance factors, PT loss, PT force range and residual drifts of shear walls subjected to lateral loads. In this research a comprehensive state-of-the-art literature review was performed on self-centring shear wall system. An extensive study was carried out to collect a database of 100 concrete, masonry, and self-centring shear wall tests from the literature. The established database was then used to review shear walls’ configurations, material, and components to benchmark requirements applicable for design purposes. The behaviour of concrete, masonry and timber shear walls were compared and critically analysed. The general behaviour, force-displacement performance of the walls, ductility, and seismic response factors, were critically reviewed and analysed for different self-centring wall systems to understand the effect of different parameters including configurations of the walls, material used for construction of the wall (concrete, masonry, timber) and axial stress ratio. The outcome of this research can be used to better understand the behaviour of self-centring wall system in order to develop design guidelines for such walls.

关键词: self-centring shear walls     rocking walls     energy dissipation     seismic performance factors     PT loss     residual drift    

Self-centring segmental retaining walls—A new construction system for retaining walls

《结构与土木工程前沿(英文)》 2021年 第15卷 第4期   页码 980-1000 doi: 10.1007/s11709-021-0737-5

摘要: This paper reports on an experimental study on a new self-centring retaining wall system. Four post-tensioned segmental retaining walls (PSRWs) were experimentally tested. Each of the walls was constructed using seven T-shaped concrete segments with a dry stack. The walls were tested under incrementally increasing cyclic lateral load. The effect of the wall height, levels of post-tensioning (PT) force, and bonded versus unbonded condition of PT reinforcement on the structural behavior of the PSRWs was investigated. The results showed that such PSRWs are structurally adequate for water retaining structures. According to the results, increasing the wall height decreases initial strength but increases the deformation capacity of the wall. The larger deformation capacity and ductility of PSRW make it a suitable structural system for fluctuating loads or deformation, e.g., seawall. It was also found that increasing the PT force increases the wall’s stiffness; however, reduces its ductility. The residual drift and the extent of damage of the unbonded PSRWs were significantly smaller than those of the bonded ones. Results suggest that this newly developed self-centring retaining wall can be a suitable structural system to retain lateral loads. Due to its unique deformation capacity and self-centring behavior, it can potentially be used for seawall application.

关键词: retaining wall     segmental     precast concrete     unbonded post-tensioning     water retaining wall     seawall    

Seismic effects on reinforcement load and lateral deformation of geosynthetic-reinforced soil walls

《结构与土木工程前沿(英文)》 2021年 第15卷 第4期   页码 1001-1015 doi: 10.1007/s11709-021-0734-8

摘要: Current design methods for the internal stability of geosynthetic-reinforced soil (GRS) walls postulate seismic forces as inertial forces, leading to pseudo-static analyses based on active earth pressure theory, which yields unconservative reinforcement loads required for seismic stability. Most seismic analyses are limited to the determination of maximum reinforcement strength. This study aimed to calculate the distribution of the reinforcement load and connection strength required for each layer of the seismic GRS wall. Using the top-down procedure involves all of the possible failure surfaces for the seismic analyses of the GRS wall and then obtains the reinforcement load distribution for the limit state. The distributions are used to determine the required connection strength and to approximately assess the facing lateral deformation. For sufficient pullout resistance to be provided by each reinforcement, the maximum required tensile resistance is identical to the results based on the Mononobe–Okabe method. However, short reinforcement results in greater tensile resistances in the mid and lower layers as evinced by compound failure frequently occurring in GRS walls during an earthquake. Parametric studies involving backfill friction angle, reinforcement length, vertical seismic acceleration, and secondary reinforcement are conducted to investigate seismic impacts on the stability and lateral deformation of GRS walls.

关键词: geosynthetics     reinforced soil     retaining walls     seismic performance    

Modeling of shear walls using finite shear connector elements based on continuum plasticity

Ulf Arne GIRHAMMAR, Per Johan GUSTAFSSON, Bo KÄLLSNER

《结构与土木工程前沿(英文)》 2017年 第11卷 第2期   页码 143-157 doi: 10.1007/s11709-016-0377-3

摘要: Light-frame timber buildings are often stabilized against lateral loads by using diaphragm action of roofs, floors and walls. The mechanical behavior of the sheathing-to-framing joints has a significant impact on the structural performance of shear walls. Most sheathing-to-framing joints show nonlinear load-displacement characteristics with plastic behavior. This paper is focused on the finite element modeling of shear walls. The purpose is to present a new shear connector element based on the theory of continuum plasticity. The incremental load-displacement relationship is derived based on the elastic-plastic stiffness tensor including the elastic stiffness tensor, the plastic modulus, a function representing the yield criterion and a hardening rule, and function representing the plastic potential. The plastic properties are determined from experimental results obtained from testing actual connections. Load-displacement curves for shear walls are calculated using the shear connector model and they are compared with experimental and other computational results. Also, the ultimate horizontal load-carrying capacity is compared to results obtained by an analytical plastic design method. Good agreements are found.

关键词: shear walls     wall diaphragms     finite element modelling     plastic shear connector     analytical modelling     experimental comparison    

Effect of earth reinforcement, soil properties and wall properties on bridge MSE walls

《结构与土木工程前沿(英文)》 2021年 第15卷 第5期   页码 1209-1221 doi: 10.1007/s11709-021-0764-2

摘要: Mechanically stabilized earth (MSE) retaining walls are popular for highway bridge structures. They have precast concrete panels attached to earth reinforcement. The panels are designed to have some lateral movement. However, in some cases, excessive movement and even complete dislocation of the panels have been observed. In this study, 3-D numerical modeling involving an existing MSE wall was undertaken to investigate various wall parameters. The effects of pore pressure, soil cohesion, earth reinforcement type and length, breakage/slippage of reinforcement and concrete strength, were examined. Results showed that the wall movement is affected by soil pore pressure and reinforcement integrity and length, and unaffected by concrete strength. Soil cohesion has a minor effect, while the movement increased by 13–20 mm for flexible geogrid reinforced walls compared with the steel grid walls. The steel grid stresses were below yielding, while the geogrid experienced significant stresses without rupture. Geogrid reinforcement may be used taking account of slippage resistance and wall movement. If steel grid is used, non-cohesive soil is recommended to minimize corrosion. Proper soil drainage is important for control of pore pressure.

关键词: mechanically stabilized earth walls     precast concrete panels     backfill soil     finite element modeling     earth reinforcement    

Self-centering steel plate shear walls for improving seismic resilience

Patricia M. CLAYTON,Daniel M. DOWDEN,Chao-Hsien LI,Jeffrey W. BERMAN,Michel BRUNEAU,Laura N. LOWES,Keh-Chuan TSAI

《结构与土木工程前沿(英文)》 2016年 第10卷 第3期   页码 283-290 doi: 10.1007/s11709-016-0344-z

摘要: As part of a Network for Earthquake Engineering Simulation research project led by researchers at the University of Washington with collaborators at University at Buffalo, and Taiwan National Center for Research on Earthquake Engineering, a self-centering steel plate shear wall (SC-SPSW) system has been developed to achieve enhanced seismic performance objectives, including recentering. The SC-SPSW consists of thin steel infill panels, referred to as web plates that serve as the primary lateral load-resisting and energy dissipating element of the system. Post-tensioned (PT) beam-to-column connections provide system recentering capabilities. A performance-based design procedure has been developed for the SC-SPSW, and a series of nonlinear response history analyses have been conducted to verify intended seismic performance at multiple hazard levels. Quasi-static subassembly tests, quasi-static and shake table tests of scaled three-story specimens, and pseudo-dynamic tests of two full-scale two-story SC-SPSWs have been conducted. As a culmination of this multi-year, multi-institutional project, this paper will present an overview of the SC-SPSW numerical and experimental research programs. This paper will also discuss innovative PT connection and web plate designs that were investigated to improve constructability, resilience, and seismic performance and that can be applied to other self-centering and steel plate shear wall systems.

关键词: self-centering     steel plate shear walls     large-scale experiment     post-tensioned connections     performance-based design    

Recent advances in geosynthetic-reinforced retaining walls for highway applications

Jie HAN, Yan JIANG, Chao XU

《结构与土木工程前沿(英文)》 2018年 第12卷 第2期   页码 239-247 doi: 10.1007/s11709-017-0424-8

摘要: Geosynthetic-reinforced retaining (GRR) walls have been increasingly used to support roadways and bridge abutments in highway projects. In recent years, advances have been made in construction and design of GRR walls for highway applications. For example, piles have been installed inside GRR walls to support bridge abutments and sound barrier walls. Geosynthetic layers at closer spacing are used in GRR walls to form a composite mass to support an integrated bridge system. This system is referred to as a geosynthetic-reinforced soil (GRS)-integrated bridge systems (IBS) or GRS-IBS. In addition, short geosynthetic layers have been used as secondary reinforcement in a GRR wall to form a hybrid GRR wall (HGRR wall) and reduce tension in primary reinforcement and facing deflections. These new technologies have improved performance of GRR walls and created more economic solutions; however, they have also created more complicated problems for analysis and design. This paper reviews recent studies on these new GRR wall systems, summarizes key results and findings including but not limited to vertical and lateral earth pressures, wall facing deflections, and strains in geosynthetic layers, discusses design aspects, and presents field applications for these new GRR wall systems.

关键词: bridge     geosynthetic     highway     reinforced     wall    

Seismic retrofit of existing SRC frames using rocking walls and steel dampers

Akira WADA, Zhe QU, Shojiro MOTOYUI, Hiroyasu SAKATA

《结构与土木工程前沿(英文)》 2011年 第5卷 第3期   页码 259-266 doi: 10.1007/s11709-011-0114-x

摘要: A retrofit of an existing 11-story steel reinforced concrete frame that features the innovative use of post-tensioned rocking walls and shear steel dampers is presented. The main components of the retrofitting plan and important design considerations are described. The retrofitting system is expected to effectively control the deformation pattern of the existing structure and significantly reduce damage to the existing structure during major earthquakes.

关键词: building structure     seismic retrofit     rocking wall     steel damper    

Seismic fragility assessment of revised MRT buildings considering typical construction changes

Rakesh DUMARU, Hugo RODRIGUES, Humberto VARUM

《结构与土木工程前沿(英文)》 2020年 第14卷 第1期   页码 241-266 doi: 10.1007/s11709-019-0560-4

摘要: The present study investigates the vulnerability assessment of the prototype revised Mandatory Rule of Thumb (MRT) buildings initially designed and detailed for three storeys bare frame building; later modified through variable number of storeys (three, four, and five) and different arrangement of infill walls (bare frame, soft-storey, irregular infilled, and fully infilled). The application of infill walls increases the fundamental frequencies, stiffness, and maximum strength capacity, but reduces the deformation capability than the bare frame building. The vulnerability was also reduced through infill walls, where the probability of exceeding partial-collapse and collapse damage reduced by 80% and 50%, respectively. Furthermore, the increased in storeys (three to five) also increases the failure probability, such that partial-collapse and collapse for fully infilled increases by almost 55% and 80%, respectively. All obtained results and discussions concluded that the structural sections and details assigned for MRT building is not sufficient if considered as bare frame and soft-storey. And increase in number of storeys causes building highly vulnerable although the infill walls were considered.

关键词: mid-rise buildings     revised NBC 205: 2012     masonry infill walls     configurations of infill walls     vulnerability assessment and inter-storey drift    

Postprocessor development for ultrasonic cutting of honeycomb core curved surface with a straight blade

《机械工程前沿(英文)》 2023年 第18卷 第1期 doi: 10.1007/s11465-022-0729-8

摘要: When ultrasonically cutting honeycomb core curved parts, the tool face of the straight blade must be along the curved surface’s tangent direction at all times to ensure high-quality machining of the curved surface. However, given that the straight blade is a nonstandard tool, the existing computer-aided manufacturing technology cannot directly realize the above action requirement. To solve this problem, this paper proposed an algorithm for extracting a straight blade real-time tool face vector from a 5-axis milling automatically programmed tool location file, which can realize the tool location point and tool axis vector conversion from the flat end mill to the straight blade. At the same time, for the multi-solution problem of the rotation axis, the dependent axis rotation minimization algorithm was introduced, and the spindle rotation algorithm was proposed for the tool edge orientation problem when the straight blade is used to machine the curved part. Finally, on the basis of the MATLAB platform, the dependent axis rotation minimization algorithm and spindle rotation algorithm were integrated and compiled, and the straight blade ultrasonic cutting honeycomb core postprocessor was then developed. The model of the machine tool and the definition of the straight blade were conducted in the VERICUT simulation software, and the simulation machining of the equivalent entity of the honeycomb core can then be realized. The correctness of the numerical control program generated by the postprocessor was verified by machining and accuracy testing of the two designed features. Observation and analysis of the simulation and experiment indicate that the tool pose is the same under each working condition, and the workpieces obtained by machining also meet the corresponding accuracy requirements. Therefore, the postprocessor developed in this paper can be well adapted to the honeycomb core ultrasonic cutting machine tool and realize high-quality and high-efficient machining of honeycomb core composites.

关键词: honeycomb core     straight blade     ultrasonic cutting     tool pose     postprocessor    

Multi-scale investigation of active failure for various modes of wall movement

《结构与土木工程前沿(英文)》 2021年 第15卷 第4期   页码 961-979 doi: 10.1007/s11709-021-0738-4

摘要: Retained backfill response to wall movement depends on factors that range from boundary conditions to the geometrical characteristic of individual particles. Hence, mechanical understanding of the problem warrants multi-scale analyses that investigate reciprocal relationships between macro and micro effects. Accordingly, this study attempts a multi-scale examination of failure evolution in cohesionless backfills. Therefore, the transition of retained backfills from at-rest condition to the active state is modeled using the discrete element method (DEM). DEM allows conducting virtual experiments, with which the variation of particle and boundary properties is straightforward. Hence, various modes of wall movement (translation and rotation) toward the active state are modeled using two different backfills with distinct particle shapes (spherical and nonspherical) under varying surcharge. For each model, cumulative rotations of single particles are tracked, and the results are used to analyze the evolution of shear bands and their geometric characteristics. Moreover, dependencies of lateral pressure coefficients and coordination numbers, as respective macro and micro behavior indicators, on particle shape, boundary conditions, and surcharge levels are investigated. Additionally, contact force networks are visually determined, and their influences on pressure distribution and deformation mechanisms are discussed with reference to the associated modes of wall movement and particle shapes.

关键词: discrete-element modelling     granular materials     retaining walls     particle shape     arching    

Establishment and verification of a shrinking core model for dilute acid hydrolysis of lignocellulose

Cunwen WANG, Xiaoling DUAN, Weiguo WANG, Zihao LI, Yuanhang QIN

《能源前沿(英文)》 2012年 第6卷 第4期   页码 413-419 doi: 10.1007/s11708-012-0212-z

摘要: The kinetics of lignocellulose hydrolysis under the conditions of high temperature and dilute acid (mass fraction 0.05%) was investigated in this paper. By studying the reducing sugar concentration versus reaction temperature (170°C–220°C) and reaction time (150–1800 s) during the hydrolysis process of five kinds of crop straw (rice, wheat, cotton, rape and corn), the shrinking core model was established, and the differential equation of the model and its analytical solution were obtained. With a numerical calculation method, the kinetic equation was estimated, and the degradation of reducing sugar obeyed first-order kinetics was obtained. The calculated results from the equations agreed well with the original experimental data. The calculation by the model showed that the reducing sugar concentration increases as the size of the particles decrease, and the uniform particles increase.

关键词: lignocellulose     dilute acid hydrolysis     shrinking core model    

Recent advances in gold-metal oxide core-shell nanoparticles: Synthesis, characterization, and their

Michelle Lukosi,Huiyuan Zhu,Sheng Dai

《化学科学与工程前沿(英文)》 2016年 第10卷 第1期   页码 39-56 doi: 10.1007/s11705-015-1551-1

摘要: Heterogeneous catalysis with core-shell structures has been a large area of focus for many years. This paper reviews the most recent work and research in core-shell catalysts utilizing noble metals, specifically gold, as the core within a metal oxide shell. The advantage of the core-shell structure lies in its capacity to retain catalytic activity under thermal and mechanical stress, which is a pivotal consideration when synthesizing any catalyst. This framework is particularly useful for gold nanoparticles in protecting them from sintering so that they retain their size, structure, and most importantly their catalytic efficiency. The different methods of synthesizing such a structure have been compiled into three categories: seed-mediated growth, post selective oxidation treatment, and one-pot chemical synthesis. The selective oxidation of carbon monoxide and reduction of nitrogen containing compounds, such as nitrophenol and nitrostyrene, have been studied over the past few years to evaluate the functionality and stability of the core-shell catalysts. Different factors that could influence the catalyst’s performance are the size, structure, choice of metal oxide shell and noble metal core and thereby the interfacial synergy and lattice mismatch between the core and shell. In addition, the morphology of the shell also plays a critical role, including its porosity, density, and thickness. This review covers the synthesis and characterization of gold-metal oxide core-shell structures, as well as how they are utilized as catalysts for carbon monoxide (CO) oxidation and selective reduction of nitrogen-containing compounds.

关键词: core-shell     characterization     core-shell structure     Different     stability    

标题 作者 时间 类型 操作

Experiment and calculation on seismic behavior of RC composite core walls with concealed steel truss

Wanlin CAO , Weihua CHANG , Changjun ZHAO , Jianwei ZHANG ,

期刊论文

Slender reinforced concrete shear walls with high-strength concrete boundary elements

期刊论文

Behaviour of self-centring shear walls——A state of the art review

期刊论文

Self-centring segmental retaining walls—A new construction system for retaining walls

期刊论文

Seismic effects on reinforcement load and lateral deformation of geosynthetic-reinforced soil walls

期刊论文

Modeling of shear walls using finite shear connector elements based on continuum plasticity

Ulf Arne GIRHAMMAR, Per Johan GUSTAFSSON, Bo KÄLLSNER

期刊论文

Effect of earth reinforcement, soil properties and wall properties on bridge MSE walls

期刊论文

Self-centering steel plate shear walls for improving seismic resilience

Patricia M. CLAYTON,Daniel M. DOWDEN,Chao-Hsien LI,Jeffrey W. BERMAN,Michel BRUNEAU,Laura N. LOWES,Keh-Chuan TSAI

期刊论文

Recent advances in geosynthetic-reinforced retaining walls for highway applications

Jie HAN, Yan JIANG, Chao XU

期刊论文

Seismic retrofit of existing SRC frames using rocking walls and steel dampers

Akira WADA, Zhe QU, Shojiro MOTOYUI, Hiroyasu SAKATA

期刊论文

Seismic fragility assessment of revised MRT buildings considering typical construction changes

Rakesh DUMARU, Hugo RODRIGUES, Humberto VARUM

期刊论文

Postprocessor development for ultrasonic cutting of honeycomb core curved surface with a straight blade

期刊论文

Multi-scale investigation of active failure for various modes of wall movement

期刊论文

Establishment and verification of a shrinking core model for dilute acid hydrolysis of lignocellulose

Cunwen WANG, Xiaoling DUAN, Weiguo WANG, Zihao LI, Yuanhang QIN

期刊论文

Recent advances in gold-metal oxide core-shell nanoparticles: Synthesis, characterization, and their

Michelle Lukosi,Huiyuan Zhu,Sheng Dai

期刊论文