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Incipient motion of sediment by turbulent kinetic energy in the presence of emergent vegetation in the outer sidewall of a bend

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ISH Journal of Hydraulic engineering 2025年第2期31卷 139-147页

作者： Rismani, Nasim Afzalimehr, Hossein Asghari-Pari, Seyed-Amin Nazari-Sharabian, Mohammad Karakouzian, Moses Department of Civil Engineering Iran University of Science and Technology Tehran Iran Department of Civil Engineering Behbahan Khatam Alanbia University of Technology Behbahan Iran Department of Mathematics Engineering and Computer Science West Virginia State University Institute WV United States Department of Civil and Environmental Engineering and Construction University of Nevada Las Vegas NV United States

This study examines the influence of vegetation on sediment movement in a 180° river bend with rigid emergent vegetation on the outer side. Using an Acoustic Doppler Velocimeter, researchers collected 504 velocity profiles under conditions with and without vegetation, across four different vegetation densities. The findings indicate that vegetation reduces the critical velocity needed for sediment movement by 59%. Additionally, the presence of vegetation increases turbulent kinetic energy, with the highest levels observed at the lowest vegetation density, and decreasing as vegetation density increases. This pattern suggests that vegetation not only modifies flow dynamics but also affects the threshold conditions for sediment transport, especially on the outer side of the bend. For example, turbulent kinetic energy is amplified 18 times at a 150-degree angle. In contrast, the bare bed exhibited minimal turbulent kinetic energy, underscoring the significant role of vegetation in altering flow structures. This study highlights the critical importance of emergent vegetation in river management and sediment control, demonstrating a more pronounced effect on the outer bend than the inner side, thus contributing to the sustainability and management of natural streams. © 2024 Indian Society for Hydraulics.

关键词： Kinetic energy

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Re-examining the Influence of End Restraint on Mechanical Behaviors of Dense Quartz Sands

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KSCE Journal of civil engineering 2024年第6期28卷 2201-2209页

作者： Yeh, Fu-Hsuan Ge, Louis Jhuo, Yu-Syuan Chen, Lv-Cun Dept. of Civil and Construction Engineering National Taiwan University of Science and Technology Taipei City10607 Taiwan Dept. of Civil Engineering National Taiwan University Taipei City10617 Taiwan

Mechanical behaviors of soils may be effectively observed, relying on precise and accurate experimental techniques adopted. The critical state of soils, therefore, can be determined through a series of conventional triaxial compression tests. However, some studies claim that the critical state may not uniquely exist under some conditions, such as end restraint, specimen size, confining pressure, initial relative densities, etc. The objective of this study is to revisit the end restraint condition where it could be negligible for specimens with a height-to-diameter ratio between 2.0 and 2.5, where the ratio is recommended by ASTM D7181-20. A ratio of 2.46 was adopted in this study to ensure proper comparisons under element testing, minimizing end-platen effects, and meeting the ASTM standards. The other aim of this study is to evaluate and compare the mechanical behaviors of the quartz sand with lubricated or nonlubricated end platens, including stress-strain-volume change and critical states. A series of consolidated-drained triaxial compression tests on quartz sand with an initial relative density of 75% and 85% were conducted. The results indicate that the end effect can be minimized when a height-to-diameter ratio is 2.46. Under the circumstances, the lubricated and nonlubricated end platens have few impacts on peak shear strength of the sands tested but they may affect the volume change behavior and the determination of critical state conditions. © Korean Society of civil Engineers 2024.

关键词： ASTM standards

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Performance evaluation of Bailey method used in asphalt mixtures containing natural river sands

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International Journal of Transportation Science and technology 2024年第4期16卷 50-67页

作者： Mohammad Ahmad Alsheyab Ahmed O.Al-sugaier Md Lutfor Rahman Hossein Emami Ahari Department of Civil Construction and Environmental EngineeringIowa State UniversityAmesIAUnited States Department of Civil Engineering Geotechnical and Materials Lab Supervisor of Jordan University of Science and TechnologyIrbidJordan

This study aims to investigate the efficiency of the Bailey method when natural sand is included in the mix at two coarseness levels of aggregate gradations:fine-graded(FG)and coarse-graided(CG),and three mixes with varing percentages of the natural river sand were prepared at each coarseness level,namely:CG with quarry sand only(CG-QS),CG with natural sands only(CG-NS),CG with quarry and natural sands(CG-QNS),FG with quarry sand only(FG-QS),FG with natural sands only(FG-NS),and FG with quarry and natural sands(CG-QNS).The portions of the natural sand either in CG-QNS and FG-QNS mixes were minimized as possible without violating the Bailey *** performance tests were utilized to evaluate the mixes including indirect tensile tension test(IDEAL-CT),disk-shaped compact tension test(DCT),flow number(FN)test,and tensile strength ratio(TSR)*** sensitivity and the significance of the volumetric measures were investigated including voids of total mix(VTM),voids of mineral aggregate(VMA),dust proportion(DP),voids filled with asphalt(VFA),air voids volume(V_(a)),and effective binder volume(Vbe),and a number of non-linear statistical models were *** results of IDEAL-CT,DCT,and FN test were consistent where CG-QNS had the best performance,followed by CG-QS,CG-NS,FG-QS,FG-QNS,and lastly *** value was always decreasing with the increase in the percentage of the natural *** was the most significant volumetric measure followed and was used to predict the performance test *** test had the highest coefficient of determination(R2)when modeled with any of the other performance tests,while TSR test had the *** Bailey gradation method was successfully proficient to provide a similar gradation coarseness for CG-QNS when compared to CG-QS which indicates a similar aggregate interlock.

关键词： Bailey gradation Asphalt mix Natural sand Performance test Non-linear regression

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Reinforcement methods of an reinforced concrete beam with the circular opening in the plastic hinge region under cyclic loading

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Advances in Structural engineering 2024年第8期27卷 1397-1414页

作者： Chiu, Chien-Kuo Sung, Hsin-Fang Chou, Jie-Ci Choudhury, Sharan Roy Department of Civil and Construction Engineering National Taiwan University of Science and Technology Taipei Taiwan Environmental Information and Engineering Department National Defense University Chung Cheng Institute of Technology Taoyuan Taiwan

Transverse opening in the plastic hinge region of reinforced concrete (RC) beam is generally not recommended due to increased risk of shear failure rather than flexure or flexure-shear failure. However, in recent years, the actual pipeline configuration requirements have posed challenges in arranging such opening in the plastic hinge region of an RC beam member. To address this issue and propose design guidelines, this work examines the mechanical behavior of nine specimens subjected to cyclic loading. The test results are compared with the design methods suggested in other guidelines and research. Additionally, a set of design guidelines and novel reinforcement methods, utilizing Double-square hoop and U-shaped stirrups, are proposed and compared with traditional reinforcement methods for RC beams with circular openings. Three distinct regions for reinforcing beams with transverse circular openings are proposed based on their distance from the column support. In the first region, extending from three times the opening diameter to one beam depth (1H), the opening is reinforced with two inclined U-shaped stirrups on each side and double-square hoops on both faces. The second region (1H to 2H) utilizes one inclined U-shaped stirrup on each side, along with double-square hoops on both faces. Beyond twice the beam depth (2H) in the third region, the opening is reinforced solely with double-square hoops on both faces. The sets of design methods provide valuable insights for future design considerations. © The Author(s) 2024.

关键词： Design

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The limitation of machine learning methods for water supply and demand forecasting: A case study for Greater Melbourne, Australia

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Water Supply 2024年第11期24卷 3848-3861页

作者： Mohammadi, Maryam Gato-Trinidad, Shirley Kuok, Kuok King Department of Civil and Construction Engineering Swinburne University of Technology HawthornVIC3122 Australia Faculty of Engineering Computing and Science Swinburne University of Technology Sarawak Campus Kuching Sarawak93350 Malaysia

Many cities around the world have faced water scarcity due to climate change, population growth, and urbanization. Accurate water supply and demand forecasting is critical for sustainable urban water management. Machine learning (ML) models provide new possibilities for forecasting compared with traditional models in handling non-linearity. This study aims to address the efficacy of ML models, long short-term memory (LSTM), stacked LSTM, bidirectional LSTM (Bi-LSTM), and multilayer perceptron (MLP), for forecasting water supply and demand in Greater Melbourne, Australia. The ML modelling utilized daily water supply and demand, and climatic variables (rainfall and maximum temperature) recorded by Melbourne Water and the Bureau of Meteorology from 1990 to 2019. The stacked LSTM performs better than other models in forecasting with R2, RMSE, and MAPE values of 0.908, 335.74 ML, and 23.5% for water supply and 0.791, 94.88 ML, and 5.3% for water demand, respectively. The inclusion of climatic variables enhanced the accuracy of forecasting by improving R2 and reducing RMSE and MAPE. The results indicate effectiveness of ML models, particularly LSTM-based architectures, in forecasting water supply and demand. However, these models have limitations, particularly in forecasting extreme values, emphasizing the need to improve ML models for more reliable and accurate water management. © 2024 The Authors.

关键词： Demand response

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Damage detection in beam-like structures using static shear energy redistribution

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Frontiers of Structural and civil engineering 2022年第12期16卷 1552-1564页

作者： Xi PENG Qiuwei YANG School of Civil and Transportation Engineering Ningbo University of TechnologyNingbo 315211China Engineering Research Center of Industrial Construction in Civil Engineering of Zhejiang Ningbo University of TechnologyNingbo 315211China

In this study,a static shear energy algorithm is presented for the damage assessment of beam-like *** to the energy release principle,the strain energy of a damaged element suddenly changes when structural damage ***,the change in the static shear energy is employed to determine the damage locations in beam-like *** static shear energy is derived from the spectral factorization of the elementary stiffness matrix and structural deflection *** advantage of using shear energy as opposed to total energy is that only a few deflection data points of the beam structure are required during the process of damage *** advantage of the proposed approach is that damage detection can be performed without establishing a structural finiteelement model in *** proposed technique is first validated using a numerical example with single,multiple,and adjacent damage scenarios.A channel steel beam and rectangular concrete beam are employed as experimental cases to further verify the proposed *** results of the simulation and experiment examples indicate that the proposed algorithm provides a simple and effective method for defect localization in beam-like structures.

关键词： damage detection beam structure strain energy static displacement variation energy damage index

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Effect Analysis of Steam Cleaning technology on Surface Damage of Stone Cultural Relics

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Journal of engineering Science and technology Review 2025年第1期18卷 39-47页

作者： Yu, Xiang Chen, Xuchen Luo, Yinke Zhong, Hao Ye, Liang Zhejiang Huadong Engineering Construction Management Co. Ltd. Hangzhou311100 China School of Civil Engineering and Architecture Zhejiang University of Science and Technology Hangzhou310023 China

Stone cultural relics, due to their significant historical value and irreproducibility, necessitate cleaning and preservation with the paramount principle of ensuring the safety of the relic itself, followed by achieving effective cleaning. Based on cultural relics from the Hangzhou region as examples, the steam cleaning experiments on limestone were conducted to investigate the impacts of various technical parameters on the surface damage of these stone relics. Through nondestructive testing methods such as infrared thermography, high-definition digital cameras, and visual observation, the changes in surface color, microstructure, mass, and temperature before and after cleaning were analyzed to assess the degree of surface damage caused by the steam cleaning parameters and to determine their safety control ranges. Results show that, the key technical parameters for the safe implementation of steam cleaning are cleaning time, cleaning distance, cleaning angle, and cleaning pressure, with cleaning time having the greatest impact on safety. The safe ranges for steam cleaning are as follows: a cleaning distance of 1-5 cm, a cleaning pressure of 2-8 bar, a cleaning angle of 30- 90°, and a cleaning time of 1-5 min. By controlling the parameters of the steam cleaning technology, the impact of steam cleaning on the surface damage of stone cultural relics can be effectively minimized, providing valuable references for practical engineering applications of stone cultural relics. © (2025), (International Hellenic University School of Science and technology). All rights reserved.

关键词： Nondestructive examination

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Effect of Sodium Alginate on the Mechanical Properties and Microstructure of Metakaolin-Based Geopolymers

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Journal of Wuhan University of technology(Materials Science) 2025年第3期40卷 700-713页

作者： WANG Zhixin FENG Yueyue RONG Xian CHEN Pang LI Yunhe ZHANG Qingtao Intelligent Construction College Shandong University of AeronauticsBinzhou 256600China School of Civil Engineering and Trans-portation Hebei University of TechnologyTianjin 300401China

Metakaolin(MK)and sodium alginate(SA)were employed as raw materials to prepare SA-MK geopolymers,which were inorganic/organic *** microscopic morphologies,mineral phases,and chemical bonds of these composites were examined using mercury intrusion porosimetry,X-ray diffraction,Fourier-transform infrared spectroscopy,and scanning electron *** low-field nuclear magnetic resonance(LF-NMR)experiments were conducted to study the water forms at different curing *** addition,fluidity,bond strength,and compressive strength measurements were conducted to determine their macroscopic mechanical *** obtained results revealed that SA addition improved the viscosity and adhesion of the geopolymer slurry and increased the adhesion strength and density of the geopolymers with low Si/Al ***,it also reduced the fluidity of the mixed slurry and shortened the operation *** the optimal amount of SA increased the compressive strength of the MK-based *** a SA content of 1.5 wt%,the 7-day strength of the geopolymer reached its maximum value of 28.3 MPa,which was 74.6%higher than that achieved without the addition of ***,the presence of SA changed the water distribution and the pore structure of the MK-based geopolymers,which strongly affected their mechanical properties.

关键词： sodium alginate-based geopolymer compressive strength microstructure LF-NMR

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Experimental and analytical investigation on friction resistance force between buried coated pressurized steel pipes and soil

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Frontiers of Structural and civil engineering 2024年第4期18卷 615-629页

作者： Shaurav ALAM Tanvir MANZUR John MATTHEWS Chris BARTLETT Erez ALLOUCHE Brent KEIL John KRAFT Department of Civil Engineering and Construction Engineering Technology Louisiana Tech UniversityRustonLA 71270USA Department of Civil Engineering Bangladesh University of Engineering and TechnologyDhaka 1000Bangladesh Georgia Tech Research Institute AtlantaGA 30332USA Stantec Inc. Edmonton T5J0K4Canada North West Pipe Company VancouverWA 98684USA

This paper presents an analytical approach for estimating frictional resistance to pipe movement at soil and external pipe surface of buried coated pressurized steel pipes relative to the internal thrust *** proposed analytical method was developed based on 36 experiments,which involved three coating types(cement mortar(CM),polyurethane type-I(PT-I),prefabricated plastic tape(PPT))on pipes’surfaces,three different soils(pea-gravel(PG),sand(S),silty-clay(SC)),and four simulated over burden depths above the pipe’s *** showed frictional resistance decreased with increasing over burden depth above the pipe’s *** degree of frictional resistance at the pipe-soil interface was found to be in the order of PG>SC>S for all coating variations and overburden *** coated pipe buried in all three types of soil produced significantly higher frictional resistance as compared to other coating *** on experimental data,the developed analytical introduced a dimensionless factor“Z”,which included effects of types of coatings,soil,and overburden depths for simplified rapid *** showed that the method provided a better prediction of frictional resistance forces,in comparison to previous analytical methods,which were barely close in predicting friction resistance for different coating variations,soil types,and overburden *** resistance force values reported herein could be considered conservative.

关键词： friction resistance force thrust force coated pressurized steel pipe soil type overburden depth

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Comparative analysis of sustainable mobility planning tools: case studies from Italy, Egypt, and Lebanon

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HBRC Journal 2025年第1期21卷 62-80页

作者： Di Ludovico, Donato Eugeni, Federico Serag, Yehya Salem, Talal Jawad, Dima Department of Civil Construction-Architectural and Environmental Engineering University of L’Aquila L’Aquila Italy Faculty of Engineering and Technology Architectural Engineering Department Future University in Egypt Cairo Egypt Civil and Environmental Engineering Department Notre Dame University-Louaize Zouk Mosbeh Lebanon Department of Mechanical Engineering Ontario Tech University ON Canada

This paper investigates the integration between different scales of sustainable mobility planning, with particular reference to the integration between Sustainable Urban Mobility Planning (SUMP) and Urban Design. It was carried out in the framework of the EU Erasmus+ UPGRADE project–Urban and transPortation reGeneration for Reducing Automobile Dependency in Middle East and North Africa–MENA area, whose cities are facing major challenges to improve their sustainable mobility. The study uses a comparative method to compare planning models and tools in the European Union, currently limited to the Italian case, with those in the MENA region currently limited to Egypt and Lebanon. On the one hand, the qualitative analysis concerns the integration between sustainable mobility planning and regional and urban spatial planning, looking for relationships (horizontal and vertical coherence checks) and criticalities between them. On the other hand, the analysis concerns the integration of the above levels and types of planning with urban design practices aimed at sustainable mobility. The application of the methodology revealed some criticalities inherent in the processes differentiated according to the countries considered, highlighting key disconnections between SUMP and Urban Mobility Design practices. The next steps of the research will be to expand the case studies and search for good practices in urban mobility design. © 2024 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.

关键词： Sustainable city

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