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Test analysis on prestressed concrete composite beams with steel boxes subjected to torsion and combined flexure and torsion

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Science China(Technological Sciences) 2012年第12期55卷 3302-3310页

作者： HU ShaoWei CHEN Liang Nanjing hydraulic research Institute Nanjing 210029China research center on New Materials in hydraulic structures Ministry of Water ResourcesNanjing 210029China

While modem prestressed techniques have improved the torsion properties of high-strength concrete （HSC） composite beams with prestressed steel （PS） boxes, no research has been reported in either the national or international literature on the an- ti-torque and composite torque properties of this type of beam. With the aim of understanding the torque properties of these beams, this paper presents results of ten comprehensive tests; three of these were based on stirrup spacings and prestressing levels as the main parameters, while the other seven were based on torsional rates. The torsion tests were conducted on the re- sults which established several key parameters, including curves of constant torsion, strain curves of steel torsion, strain distri- bution of steel beams and concrete, curves of bending-moment and mid-span deflection, as well as cross strain *** prestressing impact-factor method was adopted to deduce semiempirical equations for cracking torque in such composite beams. Furthermore, this involves the use of the equation of ultimate torque based on tress-model-theory of the distortion an- gle, the calculated results show good agreement with the measured values. In summary, this paper offers theoretical analysis for future applications of HSC composite beams with PS boxes, and provides both validation of the methods employed and a reference point for on-going research on composite beams and related anti-torque studies.

关键词： high-strength concrete composite beams prestressed steel boxes torsion property cracking torque ultimate torque combined torsion torsion-bending correlation equation

Cleaner geopolymer prepared by co-activation of gasification coal fly ash and steel slag:durability properties and economic assessment

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Frontiers of Environmental Science & Engineering 2023年第12期17卷 109-121页

作者： Xian Zhou Xia Chen Ziling Peng Yongmen Zhou Yan Li Wang Jian Zeyu Fan Yuchi Chen Key Laboratory of Geotechnical Mechanics and Engineering of Ministry of Water Resources Changjiang River Scientific Research InstituteWuhan 430010China jiangxi research center on hydraulic structures Jiangxi Provincial Institute of Water SciencesNanchang 330029China Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing 100084China

Geopolymer is a material with high early ***,the insufficient durability properties,such as long-term strength,acid-base resistance,freeze-thaw resistance,leaching toxicity,thermal stability,sulfate resistance and carbonation resistance,restrain its practical ***,a longterm stable geopolymer composite with high final strength(ASK1)was synthesized from shell coal gasification fly ash(SFA)and steel slag(SS).Additionally,a geopolymer composite with high early strength(ASK2)was also synthesized for *** results showed that ASK1 exhibited better performance on freezing-thawing resistance,carbonization resistance and heavy metals stabilization compared to the ASK2 at long-term *** the curing temperature could accelerate the unconfined compressive strength(UCS)development at initial curing ages of 3 to 7 *** ASK1 and ASK2 exhibited excellent acid-base and sulfate corrosion *** increase for UCS was seen under KOH solution and MgSO_(4)solution corrosion for *** leaching concentrations of heavy metals out of the two geopolymers were below the standard threshold,even after 50 freezingthawing *** ASK1 and ASK2 geopolymer concrete exhibited higher sustainability and economic efficiency than Portland cement *** result of this study not only provides a suitable way for the utilization of industrial solid waste in civil and environmental engineering,but also opens a new approach to improve the long-term stabilities of the geopolymers.

关键词： Geopolymer Shell coal gasification fly ash Steel slag Heavy metal Solidification/stabilization Durability

Landslide Susceptibility Mapping Using RBFN-Based Ensemble Machine Learning Models

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Computer Modeling in Engineering & Sciences 2025年第1期142卷 467-500页

作者： Landslide Susceptibility Mapping Using RBFN-Based Ensemble Machine Learning Models Duc-Dam Nguyen Nguyen Viet Tiep Quynh-Anh Thi Bui Hiep Van Le Indra Prakash Romulus Costache Manish Pandey Binh Thai Pham Faculty of Civil Engineering University of Transport TechnologyThanh XuanHa Noi100000Vietnam Faculty of hydraulic Engineering Hanoi University of Civil EngineeringHa Noi100000Vietnam DDG(R)Geological Survey of India Gandhinagar382010India research Institute of the University of Bucharest Bucharest050663Romania National Institute of Hydrology and Water Management Bucharest013686Romania Department of Civil Engineering Transilvania University of BrasovBrasov500152Romania Danube Delta National Institute for research and Development Tulcea820112Romania Marwadi University research center(MURC) Marwadi UniversityRajkotGujaratBharat360003India Department of Civil Engineering Faculty of Engineering&TechnologyMarwadi UniversityRajkotGujaratBharat360003India

This study was aimed to prepare landslide susceptibility maps for the Pithoragarh district in Uttarakhand,India,using advanced ensemble models that combined Radial Basis Function Networks(RBFN)with three ensemble learning techniques:DAGGING(DG),MULTIBOOST(MB),and ADABOOST(AB).This combination resulted in three distinct ensemble models:DG-RBFN,MB-RBFN,and ***,a traditional weighted method,Information Value(IV),and a benchmark machine learning(ML)model,Multilayer Perceptron Neural Network(MLP),were employed for comparison and *** models were developed using ten landslide conditioning factors,which included slope,aspect,elevation,curvature,land cover,geomorphology,overburden depth,lithology,distance to rivers and distance to *** factors were instrumental in predicting the output variable,which was the probability of landslide *** analysis of the models’performance indicated that the DG-RBFN model,with an Area Under ROC Curve(AUC)of 0.931,outperformed the other *** AB-RBFN model achieved an AUC of 0.929,the MB-RBFN model had an AUC of 0.913,and the MLP model recorded an AUC of *** results suggest that the advanced ensemble ML model DG-RBFN was more accurate than traditional statistical model,single MLP model,and other ensemble models in preparing trustworthy landslide susceptibility maps,thereby enhancing land use planning and decision-making.

关键词： Landslide susceptibility map spatial analysis ensemble modelling information values(IV)

Preparation and Characterization of a New Kind of Nano-rod Shaped Polycarboxylate Slump-Retaining Admixture Using for Concrete

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Journal of Shanghai Jiaotong university(Science) 2012年第5期17卷 541-544页

作者：段国荣黄国泓李爱梅祝烨然龚英 research center on New Materials in hydraulic structures of Ministry of Water Resources Nanjing Hydraulic Research Institute Nanjing R&D High Technology Co.Ltd.

A new kind of nano-rod shaped polycarboxylic acid slump-retaining agent was *** electron microscope(TEM) experiment showed that the nano-rod was bound together as macromolecular aggregates in *** performance studying suggested that this kind nano-sized polymer material had excellently plasticity-retaining performance in cement-based materials and could improve endurance performance of hardened cement-based materials *** concrete with an initial slump of 2-9 cm could achieve 3 h plasticity-retaining performance with the help of this kind *** product had extremely wide application value in the market.

关键词： nano-material polymer concrete polycarboxylate slump-retaining admixture

Improving biodegradation potential of domestic wastewater by manipulating the size distribution of organic matter

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Journal of Environmental Sciences 2016年第9期28卷 174-182页

作者： Xiang Liu Qiuwen Chen Liang Zhu College of Environment Hohai University center for Eco-Environmental research Nanjing Hydraulic Research Institute

Carbon source is a critical constraint on nutrient removal in domestic wastewater ***,the functions of particulate organic matter（POM） and some organics with high molecular weight（HMW） are overlooked in the conventional process,as they cannot be directly assimilated into cells during microbial *** further aggravates the problem of carbon source shortage and thus affects the effluent ***,to better characterize organic matter（OM） based MW distribution,microfiltration/ultrafiltration/nanofiltration（MF/UF/NF） membranes were used in parallel to fractionate OM,which obtained seven *** acidification（HA） was adopted to manipulate the MW distribution of dissolved organic matter（DOM） and further explore the correlation between molecular size and *** showed that HA pretreatment of wastewater not only promoted transformation from POM to DOM,but also boosted *** 8 hr of HA,the concentration of dissolved organic carbon（DOC） increased by 65%,from the initial value of20.25 to 33.48 mg/L,and the biodegradability index（BOD5（biochemical oxygen demand）/SCOD（soluble chemical oxygen demand）） increased from 0.52 to *** MW distribution analysis and composition optimization,a new understanding on the characteristics of organics in wastewater was obtained,which is of importance to solving low C/N wastewater treatment in engineering practice.

关键词： Domestic wastewater treatment Hydrolysis acidification Carbon source Biodegradability Molecular weight distribution

Finite particle method for kinematically indeterminate bar assemblies

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第5期10卷 669-676页

作者： Ying YU Yao-zhi LUO Space structures research center Zhejiang University Hangzhou 310058 China

This study presents a structural analysis algorithm called the finite particle method （FPM） for kinematically indeterminate bar assemblies. Different from the traditional analysis method, FPM is based on the combination of the vector mechanics and numerical calculations. It models the analyzed domain composed of finite particles. Newton＇s second law is adopted to describe the motions of all particles. A convected material flame and explicit time integration for the solution procedure is also adopted in this method. By using the FPM, there is no need to solve any nonlinear equations, to calculate the stiffness matrix or equilibrium matrix, which is very helpful in the analysis of kinematically indeterminate structures. The basic formulations for the space bar are derived, following its solution procedures for bar assemblies. Three numerical examples are analyzed using the FPM. Results obtained from both the straight pretension cable and the suspension cable assembly show that the FPM can produce a more accurate analysis result. The motion simulation of the four-bar space assembly demonstrates the capability of this method in the analysis ofkinematically indeterminate structures.

关键词： Finite particle method (FPM) Vector mechanics Convected material frame Explicit time integrations Kinematicallyindeterminate bar assemblies

hydraulics of crest spillway with large unit discharge and low Froude number

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Journal of Hydrodynamics 2015年第2期27卷 242-247页

作者：吴建华李程纯子马飞李同春吴伟伟 National Engineering research center of Water Resources Efficient Utilization and Engineering Safety College of Water Conservancy and Hydropower EngineeringHohai University hydraulic structures design division Hydrochina Huadong Engineering Corporation

With respect to the crest spillway with large unit discharge and low Froude number, the hydraulics of the slit-type energy dissipater at the outlet should be noticed due to the complicated flow regimes. In the present paper, some issues about hydraulic characteristics were experimentally investigated by means of five slit-type outlets and four tetrahedrons, including the flow choking, impact to river banks and jet trajectory. The main findings are as follows. The critical Froude number for the flow choking decreases with increasing outlet width of the slit-type energy dissipater. If the flow Froude number is expressed by the parameters just before this energy dissipater, the tetrahedron placed inside the side wall of the outlet could efficiently avoid the flow impact to the river bank of same side, and compared with the jet trajectory of the slit-type energy dissipater, the outlet with tetrahedron has different trajectory trend, i.e., the distance of the jet trajectory decreases with the increase of the water head due to special form of the outlet tetrahedron.

关键词： large unit discharge low Froude number flow choking impact to river bank jet trajectory

Out-of-plane elastic buckling load and strength design of space truss arch with a rectangular section

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Frontiers of Structural and Civil Engineering 2022年第9期16卷 1141-1152页

作者： Senping WANG Xiaolong LIU Bo YUAN Minjie SHI Yanhui WEI Space structures research center Guizhou UniversityGuiyang 550025China

The out-of-plane stability of the two-hinged space truss circular arch with a rectangular section is theoretically and numerically investigated in this ***,the flexural stiffness and torsional stiffness of space truss arches are *** calculation formula of out-of-plane elastic buckling loads of the space truss arch is derived based on the classical solution of out-of-plane flexural-torsional buckling loads of the solid web ***,since the classical solution cannot be used for the calculation of the arch with a small rise-span ratio,the formula for out-of-plane elastic buckling loads of space truss arches subjected to end bending moments is *** research of the out-of-plane stability of space truss arches under different load cases shows that the theoretical formula proposed in this paper has good ***,the design formulas to predict the out-of-plane elastoplastic stability strength of space truss arches subjected to the end bending moment and radial uniform load are presented through introducing a normalized slenderness *** assuming that all components of space truss circular arches bear only axial force,the design formulas to prevent the local buckling of chord and transverse tubes are ***,the bearing capacity design equations of space truss arches are proposed under vertical uniform load.

关键词： torsional stiffness strength design elastic buckling space truss arches out-of-plane

Experimental Study on Mechanism and Shape Characteristics of Suspended Flexible Dam

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China Ocean Engineering 2014年第6期28卷 869-878页

作者：王建中范红霞朱立俊 Nanjing hydraulic research Institute

hydraulic structures such as groin, longitudinal dike and seawall are common in water conservancy and water transportation engineering projects at home and abroad, which have long been dominated by solid mass structural form. With brush and stone as building materials, this kind of structure has an obvious engineering effect. However, it not only requires huge capital investments, but also has negative impacts on the ecological environment. The suspended flexible dam is an innovative engineering measure, and few theoretical and experimental researches of this type dam can be found at present. This paper studies the mechanism and shape characteristics of this dam and obtains the dynamic equilibrium equation of flexible dam, the float buoyancy expression, and the condition for transformation among three forms of the underwater shape of the dam. The results are valuable in engineering application and can be used as the reference for the future work due to the distinctive design philosophy, the small negative effects on environment and the consistency for sustainable development.

关键词： flexible dam suspension mechanism shape model experiment