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Seismic behavior of cantilever wall embedded in dry and saturated sand

Sanku KONAI, Aniruddha SENGUPTA, Kousik DEB

《结构与土木工程前沿(英文)》 2020年 第14卷 第3期   页码 690-705 doi: 10.1007/s11709-020-0615-6

摘要: The embedded cantilever retaining walls are often required for excavation to construct the underground facilities. Significant numbers of numerical and experimental studies have been performed to understand the behavior of embedded cantilever retaining walls under static condition. However, very limited studies have been conducted on the behavior of embedded retaining walls under seismic condition. In this paper, the behavior of a small scale model embedded cantilever retaining wall in dry and saturated sand under seismic loading condition is investigated by shake table tests in the laboratory and numerically using software FLAC2D. The embedded cantilever walls are subjected to sinusoidal dynamic motions. The behaviors of the cantilever walls in terms of lateral displacement and bending moment are studied with the variation of the two important design parameters, peak amplitude of the base motions and excavation depth. The variation of the pore water pressures within the sand is also observed in the cases of saturated sand. The maximum lateral displacement of a cantilever wall due to seismic loading is below 1% of the total height of the wall in dry sand, but in case of saturated sand, it can go up to 12.75% of the total height of the wall.

关键词: embedded cantilever wall     shake table test     FLAC2D     seismic loading     saturated and dry sand    

A hierarchical system to predict behavior of soil and cantilever sheet wall by data-driven models

Nang Duc BUI; Hieu Chi PHAN; Tiep Duc PHAM; Ashutosh Sutra DHAR

《结构与土木工程前沿(英文)》 2022年 第16卷 第6期   页码 667-684 doi: 10.1007/s11709-022-0822-4

摘要: The study proposes a framework combining machine learning (ML) models into a logical hierarchical system which evaluates the stability of the sheet wall before other predictions. The study uses the hardening soil (HS) model to develop a 200-sample finite element analysis (FEA) database, to develop the ML models. Consequently, a system containing three trained ML models is proposed to first predict the stability status (random forest classification, RFC) followed by 1) the cantilever top horizontal displacement of sheet wall (artificial neural network regression models, RANN1) and 2) vertical settlement of soil (RANN2). The uncertainty of this data-driven system is partially investigated by developing 1000 RFC models, based on the application of random sampling technique in the data splitting process. Investigation on the distribution of the evaluation metrics reveals negative skewed data toward the 1.0000 value. This implies a high performance of RFC on the database with medians of accuracy, precision, and recall, on test set are 1.0000, 1.0000, and 0.92857, respectively. The regression ANN models have coefficient of determinations on test set, as high as 0.9521 for RANN1, and 0.9988 for RANN2, respectively. The parametric study for these regressions is also provided to evaluate the relative insight influence of inputs to output.

关键词: finite element analysis     cantilever sheet wall     machine learning     artificial neural network     random forest    

Seismic analysis of semi-gravity RC cantilever retaining wall with TDA backfill

Il-Sang AHN, Lijuan CHENG

《结构与土木工程前沿(英文)》 2017年 第11卷 第4期   页码 455-469 doi: 10.1007/s11709-017-0392-z

摘要: The seismic behavior of Tire Derived Aggregate (TDA) used as backfill material of 6.10 m high retaining walls was investigated based on nonlinear time-history Finite Element Analysis (FEA). The retaining walls were semi-gravity reinforced concrete cantilever type. In the backfill, a 2.74 m thick conventional soil layer was placed over a 3.06 m thick TDA layer. For comparison purpose, a conventional all soil-backfill model was also developed, and the analysis results from the two models under the Northridge and Takatori earthquakes were compared. The FEA results showed that both models did not experience major damage in the backfill under the Northridge earthquake. However, under the Takatori earthquake, the TDA-backfill model developed substantially large displacement in the retaining walls and in the backfill compared with the soil-backfill model. Regions of large plastic strain were mainly formed in the TDA layer, and the soil over the TDA layer did not experience such large plastic strain, suggesting less damage than the soil-backfill model. In addition, the acceleration on the backfill surface of the TDA-backfill model decreased substantially compared with the soil-backfill model. If an acceleration sensitive structure is placed on the surface of the backfill, the TDA backfill may induce less damage to it.

关键词: TDA (Tire Derived Aggregate)     scrap tires     retaining wall     seismic analysis     Finite Element Analysis    

Crack detection of the cantilever beam using new triple hybrid algorithms based on Particle Swarm Optimization

Amin GHANNADIASL; Saeedeh GHAEMIFARD

《结构与土木工程前沿(英文)》 2022年 第16卷 第9期   页码 1127-1140 doi: 10.1007/s11709-022-0838-9

摘要: The presence of cracks in a concrete structure reduces its performance and increases in the size of cracks result in the failure of the structure. Therefore, the accurate determination of crack characteristics, such as location and depth, is one of the key engineering issues for assessment of the reliability of structures. This paper deals with the inverse analysis of the crack detection problems using triple hybrid algorithms based on Particle Swarm Optimization (PSO); these hybrids are Particle Swarm Optimization-Genetic Algorithm-Firefly Algorithm (PSO-GA-FA), Particle Swarm Optimization-Grey Wolf Optimization-Firefly Algorithm (PSO-GWO-FA), and Particle Swarm Optimization-Genetic Algorithm-Grey Wolf Optimization (PSO-GA-GWO). A strong correlation exists between the changes in the natural frequency of a concrete beam and the crack parameters. Thus, the location and depth of a crack in a beam can be predicted by measuring its natural frequency. Hence, the measured natural frequency can be used as the input parameter of the algorithm. In this paper, this is applied to identify crack location and depth in a cantilever beam using the new hybrid algorithms. The results show that among the proposed triple hybrid algorithms, the PSO-GA-FA and PSO-GWO-FA algorithms are much more effective than PSO-GA-GWO algorithm for the crack detection.

关键词: crack     cantilever beam     triple hybrid algorithms     Particle Swarm Optimization    

A preliminary research on wireless cantilever beam vibration sensor in bridge health monitoring

Xinlong TONG, Shanglin SONG, Linbing WANG, Hailu YANG

《结构与土木工程前沿(英文)》 2018年 第12卷 第2期   页码 207-214 doi: 10.1007/s11709-017-0406-x

摘要: According to specific bridge environment, optimal design piezoelectric cantilever beam structure by using results of theoretical calculations and simulation, verify natural frequencies of piezoelectric cantilever beam and production ability of data by experiment, thus formed a complete set of design method of piezoelectric cantilever beam. Considering natural frequency of vibration and intensity of the beam body, design a new type of piezoelectric cantilever beam structure. Paper analyzes the principle of sensor data acquisition and transmission, design a hardware integration system include signal conversion module, microcontroller module and wireless transmission module, test local read and wireless transmission for the combination structure of cantilever beam and data collection card, experimental verification of the radio piezoelectric vibrating cantilever vibration response is intact, the beam produced signal by vibration, acquisition card converts and wireless transmit data, this proved a good and intuitive linear response in simulation of bridge vibration test. Finally, the paper designed a kind of new wireless sensor of vibration cantilever beam, suitable for small bridge health monitoring based on Internet of things.

关键词: piezoelectric cantilever beam     bridge     natural frequency     wireless sensor    

Torsional vibrations of a cylindrical foundation embedded in a saturated poroelastic half-space

Dazhi WU,Lu YU

《结构与土木工程前沿(英文)》 2015年 第9卷 第2期   页码 194-202 doi: 10.1007/s11709-015-0292-z

摘要: Considering the interactions between an embedded foundation and saturated soil, the torsional vibrations of a cylindrical foundation embedded in a saturated poroelastic medium are analyzed in this paper. Both a rigid foundation and an elastic foundation are considered. Assuming both the side surface and the bottom surface of the foundation are perfectly bonded to soil, the reaction torques that the side soil and bottom soil acting on the foundation can be gained from basic dynamic equations of the poroelastic medium. According to the dynamic equilibrium equations of a foundation under harmonic torque, the torsional vibrations of an embedded cylindrical foundation are presented. Besides, the angular amplitude of the foundation, the equivalent stiffness and damping coefficients of the soil are expressed explicitly. Selected examples are presented to investigate the influence of relevant parameters on the torsional vibrations.

关键词: embedded foundation     saturated soil     rigid foundation     elastic foundation     torsional vibration    

optimization for tailoring the ratio between two flexural eigenfrequencies of atomic force microscopy cantilever

Qi XIA,Tao ZHOU,Michael Yu WANG,Tielin SHI

《机械工程前沿(英文)》 2014年 第9卷 第1期   页码 50-57 doi: 10.1007/s11465-014-0286-x

摘要:

In an operation mode of atomic force microscopy that uses a higher eigenmode to determine the physical properties of material surface, the ratio between the eigenfrequency of a higher flexural eigenmode and that of the first flexural eigenmode was identified as an important parameter that affects the sensitivity and accessibility. Structure features such as cut-out are often used to tune the ratio of eigenfrequencies and to enhance the performance. However, there lacks a systematic and automatic method for tailoring the ratio. In order to deal with this issue, a shape and topology optimization problem is formulated, where the ratio between two eigenfrequencies is defined as a constraint and the area of the cantilever is maximized. The optimization problem is solved via the level set based method.

关键词: atomic force microscopy     cantilever probe     eigenfrequency     optimization    

Shear strength model of the reinforced concrete beams with embedded through-section strengthening bars

Linh Van Hong BUI; Phuoc Trong NGUYEN

《结构与土木工程前沿(英文)》 2022年 第16卷 第7期   页码 843-857 doi: 10.1007/s11709-022-0834-0

摘要: In this study, finite element (FE) analysis is utilized to investigate the shear capacity of reinforced concrete (RC) beams strengthened with embedded through-section (ETS) bars. Effects of critical variables on the beam shear strength, including the compressive strength of concrete, stiffness ratio between ETS bars and steel stirrups, and use of ETS strengthening system alone, are parametrically investigated. A promising method based on the bond mechanism between ETS strengthening and concrete is then proposed for predicting the shear resistance forces of the strengthened beams. An expression for the maximum bond stress of the ETS bars to concrete is developed. This new expression eliminates the difficulty in the search and selection of appropriate bond parameters from adhesion tests. The results obtained from the FE models and analytical models are validated by comparison with those measured from the experiments. Consequently, the model proposed in this study demonstrates better performance and more accuracy for prediction of the beam shear-carrying capacity than those of existing models. The results obtained from this study can also serve researchers and engineers in selection of the proper shear strength models for design of ETS-strengthened RC beams.

关键词: embedded through-section     strengthening     fiber-reinforced polymer     finite element     shear strength model     bond mechanism    

Modeling and analysis of controllable output property of cantilever-beam inertial sensors based on magnetic

Guixiong LIU, Peiqiang ZHANG, Chen XU

《机械工程前沿(英文)》 2009年 第4卷 第2期   页码 129-133 doi: 10.1007/s11465-009-0035-8

摘要: Magnetic fluid is first introduced into the traditional cantilever-beam senor. Based on the property of the cantilever-beam and the novel controllable mag-viscosity of magnetic fluid, the output of cantilever-beam sensors is under control so that the controllable output of the sensors can be realized. The mathematical model of the sensors is established and analyzed. The dynamic control function and the following educational results, which include the two curves of the displacement ratio and phase function with the different damping ratio and frequency ratio, are obtained based on the model. The result shows that it is valid to realize the controllable output of the sensors by controlling the viscosity of the magnetic fluid, and finally the expanded measurement range can be realized.

关键词: sensors     magnetic fluid     property of mag-viscosity     controllable output    

Heat-spreading analysis of a heat sink base embedded with a heat pipe

B. V. BORGMEYER, H. B. MA,

《能源前沿(英文)》 2010年 第4卷 第2期   页码 143-148 doi: 10.1007/s11708-010-0013-1

摘要: A simplified model predicting the heat transfer performance of a heat sink base with a high thermal conductivity was developed. Numerical analysis was performed using the commercial software FLUENT. The investigation indicates that for heat sink bases with a high effective thermal conductivity, such as the base embedded with a typical heat pipe, the entire heat sink can be modeled as a flat plate with a uniform temperature and an effective convection heat transfer coefficient. This simplified model can be used to determine the heat transfer performance of a heat sink embedded with a typical heat pipe or vapor chamber.

关键词: heat pipe     heat sink     microprocessor heat removal    

Preparation of nZVI embedded modified mesoporous carbon for catalytic persulfate to degradation of reactive

《环境科学与工程前沿(英文)》 2021年 第15卷 第5期 doi: 10.1007/s11783-020-1372-4

摘要:

• The MCNZVI is prepared as an interesting material for PS activation.

关键词: MCNZVI     Core-shell structure     Reactive Black 5     Persulfate     Mechanism    

Numerical simulation of squat reinforced concrete wall strengthened by FRP composite material

Ali KEZMANE,Said BOUKAIS,Mohand Hamizi

《结构与土木工程前沿(英文)》 2016年 第10卷 第4期   页码 445-455 doi: 10.1007/s11709-016-0339-9

摘要: The advanced design rules and the latest known earthquakes, have imposed a strengthening of reinforced concrete structures. Many research works and practical achievements of the application of the external reinforcement by using FRP composite materials have been particularly developed in the recent years. This type of strengthening seems promising for the seismic reinforcement of buildings. Among of the components of structures that could affect the stability of the structure in case of an earthquake is the reinforced concrete walls, which require in many cases a strengthening, especially in case where the diagonal cracks can be developed. The intent of this paper is to present a numerical simulation of squat reinforced concrete wall strengthened by FRP composite material (carbon fiber epoxy). The intent of this study is to perform finite element model to investigate the effects of such reinforcement in the squat reinforced concrete walls. Taking advantage of a commercial finite element package ABAQUS code, three-dimensional numerical simulations were performed, addressing the parameters associated with the squat reinforced concrete walls. An elasto-plastic damage model material is used for concrete, for steel, an elastic-plastic behavior is adopted, and the FRP composite is considered unidirectional and orthotropic. The obtained results in terms of displacements, stresses, damage illustrate clearly the importance of this strengthening strategy.

关键词: simulation     strengthening     reinforced concrete wall     squat wall     FRP composite material     damage     Abaqus    

Nonlinear analysis of pre-tensioned glass wall facade by stability function with initial imperfection

Siu-Lai CHAN, Yaopeng LIU, Andy LEE,

《结构与土木工程前沿(英文)》 2010年 第4卷 第3期   页码 376-382 doi: 10.1007/s11709-010-0086-2

摘要: Pre-tensioned high strength trusses using alloy steel bar are widely used as glass wall supporting systems because of the high degree of transparency. The breakage of glass panes in this type of system occurs occasionally, likely to be due to error in design and analysis in addition to other factors like glass impurity and stress concentration around opening in a spider system. Most design does not consider the flexibility of supports from finite stiffness of supporting steel or reinforced concrete beams. The resistance of lateral wind pressure of the system makes use of high tension force coupled with the large deflection effect, both of which are affected by many parameters not generally considered in conventional structures. In the design, one must therefore give a careful consideration on various effects, such as support settlement due to live loads and material creep, temperature change, pre-tension force, and wind pressure. It is not uncommon to see many similar glass wall systems fail in the wind load test chambers under a design wind speed. This paper presents a rigorous analysis and design of this type of structural systems used in a project in Hong Kong, China. The stability function with initial curvature is used in place of the cubic function, which is only accurate for linear analysis. The considerations and analysis techniques are believed to be of value to engineers involved in the design of the structural systems behaving nonlinearly.

关键词: tension system     glass wall     nonlinear analysis     pre-tensioning     second-order analysis    

Immobilization and characterization of the mycelia-embedded polylysine-alginate beads and their decolorization

《化学科学与工程前沿(英文)》 2023年 第17卷 第12期   页码 2001-2013 doi: 10.1007/s11705-023-2341-9

摘要: Liquid fermented fungal mycelia with decolorization capability have potential applications in scale-up. In this work, the Lactarius deliciosus mycelia were immobilized on -polylysine-alginate beads, and the decolorization effects of -polylysine-alginate beads were demonstrated along with Coomassie brilliant blue G-250 as a model dye. Morphology observation confirmed the beads had an exterior film and interior capsule with honeycomb microstructures suitable for mycelia growth. It was manifested that the maximum decolorization efficiency for mycelia was 98.5% at a removal rate of 0.68 mg·L‒1·h after 3 days. In comparison, the decolorization efficiency of the immobilized mycelia reached the maximum value of 97.3% at a removal rate of 6.1 mg·L‒1·h after 8 h. The enzyme activities of lignin peroxidase and laccase tested in the immobilized mycelia were significantly higher than in that of the free ones, such as the lignin peroxidase had the highest enzyme activity of 77.6 ± 7.4 U·L‒1 in the former, while of 27.4 ± 8.7 U·L‒1 in the latter. The immobilization of L. deliciosus mycelia could improve the decolorization of Coomassie brilliant blue G-250 efficiently. The prepared -polylysine-alginate beads embedded with L. deliciosus mycelia have very good reusability and a great potential in decolorizing analog dyes.

关键词: Lactarius deliciosus mycelia     immobilization     decolorization     polylysine-alginate beads     Coomassie brilliant blue G-250    

Diaphragm wall-soil-cap interaction in rectangular-closed- diaphragm-wall bridge foundations

Hua WEN, Qiangong CHENG, Fanchao MENG, Xiaodong CHEN

《结构与土木工程前沿(英文)》 2009年 第3卷 第1期   页码 93-100 doi: 10.1007/s11709-009-0015-4

摘要: Rectangular-closed-diaphragm-wall foundation is a new type of bridge foundation. Diaphragm wall-soil-cap interaction was studied using a model test. It was observed that the distribution of soil resistance under the cap is not homogeneous. The soil resistance in the corner under the cap is larger than that in the border; and that in the center is the smallest. The distribution of soil resistance under the cap will be more uniform, if the sectional area of soil core is enlarged within a certain range. Due to the existence of cap, there is a “weakening effect” in inner shaft resistance of the upper wall segments, and there is “enhancement effect” in the lower wall segments and in toe resistance. The load shearing percentage of soil resistance under the cap is 10%-20%. It is unreasonable to ignore the effects of the cap and the soil resistance under the cap in bearing capacity calculations.

关键词: diaphragm wall     bridge foundation     low cap     interaction    

标题 作者 时间 类型 操作

Seismic behavior of cantilever wall embedded in dry and saturated sand

Sanku KONAI, Aniruddha SENGUPTA, Kousik DEB

期刊论文

A hierarchical system to predict behavior of soil and cantilever sheet wall by data-driven models

Nang Duc BUI; Hieu Chi PHAN; Tiep Duc PHAM; Ashutosh Sutra DHAR

期刊论文

Seismic analysis of semi-gravity RC cantilever retaining wall with TDA backfill

Il-Sang AHN, Lijuan CHENG

期刊论文

Crack detection of the cantilever beam using new triple hybrid algorithms based on Particle Swarm Optimization

Amin GHANNADIASL; Saeedeh GHAEMIFARD

期刊论文

A preliminary research on wireless cantilever beam vibration sensor in bridge health monitoring

Xinlong TONG, Shanglin SONG, Linbing WANG, Hailu YANG

期刊论文

Torsional vibrations of a cylindrical foundation embedded in a saturated poroelastic half-space

Dazhi WU,Lu YU

期刊论文

optimization for tailoring the ratio between two flexural eigenfrequencies of atomic force microscopy cantilever

Qi XIA,Tao ZHOU,Michael Yu WANG,Tielin SHI

期刊论文

Shear strength model of the reinforced concrete beams with embedded through-section strengthening bars

Linh Van Hong BUI; Phuoc Trong NGUYEN

期刊论文

Modeling and analysis of controllable output property of cantilever-beam inertial sensors based on magnetic

Guixiong LIU, Peiqiang ZHANG, Chen XU

期刊论文

Heat-spreading analysis of a heat sink base embedded with a heat pipe

B. V. BORGMEYER, H. B. MA,

期刊论文

Preparation of nZVI embedded modified mesoporous carbon for catalytic persulfate to degradation of reactive

期刊论文

Numerical simulation of squat reinforced concrete wall strengthened by FRP composite material

Ali KEZMANE,Said BOUKAIS,Mohand Hamizi

期刊论文

Nonlinear analysis of pre-tensioned glass wall facade by stability function with initial imperfection

Siu-Lai CHAN, Yaopeng LIU, Andy LEE,

期刊论文

Immobilization and characterization of the mycelia-embedded polylysine-alginate beads and their decolorization

期刊论文

Diaphragm wall-soil-cap interaction in rectangular-closed- diaphragm-wall bridge foundations

Hua WEN, Qiangong CHENG, Fanchao MENG, Xiaodong CHEN

期刊论文