The North Qilian Shan fold and thrust belt,located at the northern Tibetan Plateau and southern margin of the Hexi Corridor,is a key tectonic unit to decode the formation and expansion of the plateau.Previous studies ...The North Qilian Shan fold and thrust belt,located at the northern Tibetan Plateau and southern margin of the Hexi Corridor,is a key tectonic unit to decode the formation and expansion of the plateau.Previous studies emphasize the Cenozoic deformation due to the far-field response to the Indo-Asian collision,but the Mesozoic deformations are poorly constrained in this area.We conducted detailed field mapping,structural analysis,geochronology,and structural interpretation of deep seismic reflectional profiling and magnetotelluric(MT)sounding,to address the superposed results of the Mesozoic and Cenozoic deformation.The results recognized the North Qilian thrust and nappe system(NQTS),the root and the frontal belt are the North Qilian thrust(NQT),and the Yumu Shan klippe(YK),respectively.The middle belt is located between the NQT and the YK.Monzonitic granite zircon U-Pb dating from the middle belt yields an age of ca.415 Ma,which is similar to south NQT.The thrusting displacement is estimated at ca.48 km by structural interpretation of deep profiles.The timing is constrained in the early stage of the Early Cretaceous by the formation of simultaneous growth strata.We suggest that the NQTS has resulted from the far-field effect of the Lhasa-Qiangtang collision,and the Yumu Shan is uplifted by the superposed Cenozoic deformation.展开更多
Purpose of present work is to develop a reliable and simple method for structural analysis of RC Shear Walls. The shear wall is simulated by a truss model as the bar of a truss is the simplest finite element. An itera...Purpose of present work is to develop a reliable and simple method for structural analysis of RC Shear Walls. The shear wall is simulated by a truss model as the bar of a truss is the simplest finite element. An iterative method is used. Initially, there are only concrete bars. Repeated structural analyses are performed. After each structural analysis, every concrete bar exceeding tensile strength is replaced by a steel bar. For every concrete bar exceeding compressive strength, first its section area is increased. If this is not enough, a steel bar is placed at the side of it. For every steel bar exceeding tensile or compressive strength, its section area is increased. After the end of every structural analysis, if all concrete and steel bars fall within tensile and compressive strengths, the output data are written and the analysis is terminated. Otherwise, the structural analysis is repeated. As all the necessary conditions (static, elastic, linearized geometric) are satisfied and the stresses of ALL concrete and steel bars fall within the tensile and compressive strengths, the results are acceptable. Usually, the proposed method exhibits a fast convergence in 4 - 5 repeats of structural analysis of the RC Shear Wall.展开更多
This paper introduces a new version of the open-source educational software, LESM (Linear Elements Structure Model), developed in MATLAB for structural analysis of one-dimensional models such as frames, trusses, and g...This paper introduces a new version of the open-source educational software, LESM (Linear Elements Structure Model), developed in MATLAB for structural analysis of one-dimensional models such as frames, trusses, and grillages. The updated program includes dynamic analysis, which incorporates inertial and damping effects, time-dependent load conditions, and a transient solver with multiple time integration schemes. The software assumes small displacements and linear-elastic material behavior. The paper briefly explains the theoretical basis for these developments and the reorganization of the source code using Object-Oriented Programming (OOP). The updated Graphical User Interface (GUI) allows interactive use of dynamic analysis features and displays new results such as animations, envelope diagrams of internal forces, phase portraits, and the response of degrees-of-freedom in time and frequency domain. The new version was used in a structural dynamics course, and new assignments were elaborated to improve students’ understanding of the subject.展开更多
With great superiorities in energy density,rate capability and structural stability,Na_(3)V_(2)(PO_(4))_(2) F_(3)(NVPF)has attracted much attentions as cathode of sodium ion battery(SIB),but it also faces challenges o...With great superiorities in energy density,rate capability and structural stability,Na_(3)V_(2)(PO_(4))_(2) F_(3)(NVPF)has attracted much attentions as cathode of sodium ion battery(SIB),but it also faces challenges on its poor intrinsic electronic conductivity and the controversial de/sodiation mechanism.Herein,a series of Zr-doped NVPF coated by N-doped carbon layer(~5 nm in thickness,homogenously)materials are fabricated by a sol-gel method,and the optimized heteroatom-doping amounts of Zr and N doping improve intrinsic properties on enlarging lattice distance and enhancing electronic conductivity,respectively.Specifically,among all samples of Na_(3) V_(2-x)Zr_(x)(PO_(4))_(2) F_(3)/NC(NVPF-Zr-x/NC,x=0,0.01,0.02,0.05,and 0.1),the optimized electrode of NVPF-Zr-0.02/NC delivers high reversible capacities(119.2 mAh g^(-1) at0.5 C),superior rate capability(98.1 mA h g^(-1) at 20 C)and excellent cycling performance.The structural evolution of NVPF-Zr-0.02/NC electrode,in-situ monitored by X-ray diffractometer,follows a step-wise Na-extraction/intercalation mechanism with reversible multi-phase changes,not just a solid-solutionreaction one.Full cells of NVPF-Zr-0.02/NC//hard carbon demonstrate high capacity(99.8 mA h g^(-1) at 0.5 C),high out-put voltage(3.5 V)and good cycling stability.This work is favorable to accelerate the development of high-performance cathode materials and explore possible redox reaction mechanisms of SIBs.展开更多
A better understanding of the relationship between the structure and functions of urban and suburban spaces is one of the avenues of research still open for geographical information science.The research presented in t...A better understanding of the relationship between the structure and functions of urban and suburban spaces is one of the avenues of research still open for geographical information science.The research presented in this paper develops several graph-based metrics whose objective is to characterize some local and global structural properties that reflect the way the overall building layout can be cross-related to the one of the road layout.Such structural properties are modeled as an aggregation of parcels,buildings,and road networks.We introduce several computational measures(Ratio Minimum Distance,Minimum Ratio Minimum Distance,and Metric Compactness)that respectively evaluate the capability for a given road to be connected with the whole road network.These measures reveal emerging sub-network structures and point out differences between less-connective and moreconnective parts of the network.Based on these local and global properties derived from the topological and graph-based representation,and on building density metrics,this paper proposes an analysis of road and building layouts at different levels of granularity.The metrics developed are applied to a case study in which the derived properties reveal coherent as well as incoherent neighborhoods that illustrate the potential of the approach and the way buildings and roads can be relatively connected in a given urban environment.Overall,and by integrating the parcels and buildings layouts,this approach complements other previous and related works that mainly retain the configurational structure of the urban network as well as morphological studies whose focus is generally limited to the analysis of the building layout.展开更多
The water-soluble polysaccharide LBP-1 was isolated and characterized from Lycium barbarum L.LBP-1 was mainly composed of arabinose,galactose,glucose,xylose,mannose at a molar ratio of 37.53:28.08:14.72:7.83:4.50,resp...The water-soluble polysaccharide LBP-1 was isolated and characterized from Lycium barbarum L.LBP-1 was mainly composed of arabinose,galactose,glucose,xylose,mannose at a molar ratio of 37.53:28.08:14.72:7.83:4.50,respectively.Based on nuclear magnetic resonance(NMR)and methylation analysis,the backbone of LBP-1 was speculated in theα-L-Ara(1→[5-α-L-Ara(1→3)-β-D-Galp-(1→]n→4)-α-D-Galp-(1[→5-α-L-Ara(1]n[→6)-β-D-Galp-(1→4)-β-D-Galp-(1→]n,and the side chains of LBP-1 were in theα-L-Ara(1→3)-β-D-Galp-(1→6 position.These results showed that LBP-1 inhibited the growth of cancer A549 cells through cell cycle arrest and apoptosis,with an IC50 value of 42.5μg/mL.In addition,LBP-1 altered the expression of Cyclin D1,Cyclin D3,and CDK 2,thus blocking the cell cycle in G0/G1 phase,reducing cell migration,and regulating the PI3K/Akt/mTOR signaling pathway to induce apoptosis.展开更多
This paper deals with the structural analysis problem of dynamic lumped process high-index differential algebraic equations(DAE)models.The existing graph theoretical method depends on the change in the relative positi...This paper deals with the structural analysis problem of dynamic lumped process high-index differential algebraic equations(DAE)models.The existing graph theoretical method depends on the change in the relative position of underspecified and overspecified subgraphs and has an effect to the value of the differential index for complex models.In this paper,we consider two methods for index reduction of such models by differentiation:Pryce’s method and the symbolic differential elimination algorithm rifsimp.They can remedy the above drawbacks.Discussion and comparison of these methods are given via a class of fundamental process simulation examples.In particular,the efficiency of Pryce’s method is illustrated as a function of the number of tanks in process design.Moreover,a range of nontrivial problems are demonstrated by the symbolic differential elimination algorithm and fast prolongation.展开更多
Quantitative analysis on cutting notch of tea stalk is one method to better understand shear resistance and mechanical properties of the stalk,which could improve cutting performance and efficiency for tea harvesting....Quantitative analysis on cutting notch of tea stalk is one method to better understand shear resistance and mechanical properties of the stalk,which could improve cutting performance and efficiency for tea harvesting.Optimal design of the cutter might be achieved through structural analysis of cutting notch by X-ray micro-computed tomography(micro-CT).The third inter-node of the stalks were sampled and scanned by micro-CT after they were cut at different cutting depths(0.7,1.5,2.3 mm)and cutting edge angles of cutter(30,35,40).The structural change of the cutting notch and cutting force was observed.Grey-scale histogram analysis and bimodal segmentation method were used to extract the information about cutting notch from 2D slice images.A 3D model of the stalk was established with reconstruction and volume rendering.Besides,maximum crosssectional area ratio of cutting notch(MCSARCN)and volume ratio of cutting notch(VRCN)were calculated.The results show that MCSARCN and VRCN had a closely relationship with the cutting force,cutting depth and cutting edge angle according to 3D tomographic images and 2D slice images.Both MCSARCN and VRCN increased with cutting depth,despite of cutting edge angle.For cutting edge angle of 30,35and 40at different cutting depths,MCSARCN increased from 4.89%to 9.47%,from 8.51%to 22.83%and from 4.30%to 16.87%,respectively.Meanwhile,VRCN increased from 1.59%to 2.13%,from 2.98%to 5.76%and from 3.04%to 5.01%,respectively.When cutting depth was 1.5 mm,cutting force increased but VRCN present a decreased trend with cutting edge angle.X-ray micro-CT could be used to analyze the structure on cutting notch of tea stalks which is helpful in optimizing the structural parameters of the cutter.展开更多
Structural analysis problems can be formulized as either root finding problems,or optimization problems.The general practice is to choose the first option directly or to convert the second option again to a root findi...Structural analysis problems can be formulized as either root finding problems,or optimization problems.The general practice is to choose the first option directly or to convert the second option again to a root finding problem by taking relevant derivatives and equating them to zero.The second alternative is used very randomly as it is and only for some simple demonstrative problems,most probably due to difficulty in solving optimization problems by classical methods.The method called TPO/MA(Total Potential Optimization using Metaheuristic Algorithms)described in this study successfully enables to handle structural problems with optimization formulation.Using metaheuristic algorithms provides additional advantages in dealing with all kinds of constraints.展开更多
The suspension coil spring is one of the most important components in a vehicle suspension system. Its primary function is to absorb the vibrational shocks that are occasioned by irregular road surface to provide the ...The suspension coil spring is one of the most important components in a vehicle suspension system. Its primary function is to absorb the vibrational shocks that are occasioned by irregular road surface to provide the vehicle with stability and ride comfort. The main objective of this study is to design a suspension coil spring made of structural steel for light duty vehicles with the aim of weight and cost reduction. This study was motivated by the government of Ghana’s actions to industrialise the automotive sector of the country through government policies and programs. The study made use of high carbon steel and low carbon steel as the control materials and structural steel as the implementing material. This was done to determine the suitability of structural steel for vehicle suspension coil spring. The study analysed parameters such as total deformation, equivalent Von Mises stress, maximum shear stress, and safety factor in the static structural analysis. The fatigue analysis also analysed parameters such as fatigue life and fatigue alternating stress. The results of the study revealed that the suspension spring made of structural steel has superior properties against all the parameters set for this study apart from deformation. The two control materials that are known for suspension coil spring design and manufacture have better properties to withstand deformation than the implementing material.展开更多
A hierarchical structural decomposition analysis(SDA) model has been developed based on process-level input-output(I-O) tables to analyze the drivers of energy consumption changes in an integrated steel plant during 2...A hierarchical structural decomposition analysis(SDA) model has been developed based on process-level input-output(I-O) tables to analyze the drivers of energy consumption changes in an integrated steel plant during 2011-2013. By combining the principle of hierarchical decomposition into D&L method, a hierarchical decomposition model for multilevel SDA is obtained. The developed hierarchical IO-SDA model would provide consistent results and need less computation effort compared with the traditional SDA model. The decomposition results of the steel plant suggest that the technology improvement and reduced steel final demand are two major reasons for declined total energy consumption. The technical improvements of blast furnaces, basic oxygen furnaces, the power plant and the by-products utilization level have contributed mostly in reducing energy consumption. A major retrofit of ancillary process units and solving fuel substitution problem in the sinter plant and blast furnace are important for further energy saving. Besides the empirical results, this work also discussed that why and how hierarchical SDA can be applied in a process-level decomposition analysis of aggregated indicators.展开更多
In this paper, the fuzzy-set-based structural possibility theory is investigated, and this theory can be used to deal with the subjective uncertainties in the design of engineering structures. Furthermore, a comprehen...In this paper, the fuzzy-set-based structural possibility theory is investigated, and this theory can be used to deal with the subjective uncertainties in the design of engineering structures. Furthermore, a comprehensive model of structural safety assessment, which can merge subjective uncertainties with objective uncertainties, is presented. In this model, the fuzziness of stress-strength inference model, safety margin functions of single or multiple limit-state, structural failure state and the final assessment result are taken into account. This continuous model can be transformed into an equivalent model of probability-based and solved by the present structural reliability analysis method and parallel algorithm. An example is given to show the main idea of the method presented in this paper.展开更多
This paper studies the deterioration of bridge substructures utilizing the Long-Term Bridge Performance(LTBP)Program InfoBridge^(TM)and develops a survival model using Cox proportional hazards regression.The survival ...This paper studies the deterioration of bridge substructures utilizing the Long-Term Bridge Performance(LTBP)Program InfoBridge^(TM)and develops a survival model using Cox proportional hazards regression.The survival analysis is based on the National Bridge Inventory(NBI)dataset.The study calculates the survival rate of reinforced and prestressed concrete piles on bridges under marine conditions over a 29-year span(from 1992 to 2020).The state of Maryland is the primary focus of this study,with data from three neighboring regions,the District of Columbia,Virginia,and Delaware to expand the sample size.The data obtained from the National Bridge Inventory are condensed and filtered to acquire the most relevant information for model development.The Cox proportional hazards regression is applied to the condensed NBI data with six parameters:Age,ADT,ADTT,number of spans,span length,and structural length.Two survival models are generated for the bridge substructures:Reinforced and prestressed concrete piles in Maryland and reinforced and prestressed concrete piles in wet service conditions in the District of Columbia,Maryland,Delaware,and Virginia.Results from the Cox proportional hazards regression are used to construct Markov chains to demonstrate the sequence of the deterioration of bridge substructures.The Markov chains can be used as a tool to assist in the prediction and decision-making for repair,rehabilitation,and replacement of bridge piles.Based on the numerical model,the Pile Assessment Matrix Program(PAM)is developed to facilitate the assessment and maintenance of current bridge structures.The program integrates the NBI database with the inspection and research reports from various states’department of transportation,to serve as a tool for condition state simulation based on maintenance or rehabilitation strategies.展开更多
Plant-based fermentations provide an untapped source for novel biotechnological applications.In this study,a probiotic named Lactobacillus fermentum 21828 was introduced to ferment Lentinus edodes.Polysaccharides were...Plant-based fermentations provide an untapped source for novel biotechnological applications.In this study,a probiotic named Lactobacillus fermentum 21828 was introduced to ferment Lentinus edodes.Polysaccharides were extracted from fermented and non-fermented L.edodes and purified via DEAE-52 and Sephadex G-100.The components designated F-LEP-2a and NF-LEP-2a were analyzed by FT-IR,HPGPC,HPAEC,SEM,GC-MS and NMR.The results revealed that probiotic fermentation increased the molecular weight from 1.16×10^(4) Da to 1.87×10^(4) Da and altered the proportions of glucose,galactose and mannose,in which glucose increased from 45.94%to 48.16%.Methylation analysis and NMR spectra indicated that F-LEP-2a and NF-LEP-2a had similar linkage patterns.Furthermore,their immunomodulatory activities were evaluated with immunosuppressive mice.NF-LEP and F-LEP improved immune organ indices,immunoglobulin(Ig G and Ig M)and cytokines concentrations;restored the antioxidation capacity of liver;and maintained the balance of gut microbiota.F-LEP displayed better moderating effects on the spleen index,immunoglobulin,cytokines and the diversity of gut microbiota than NF-LEP(200,400 mg/kg).Our study provides an efficient and environment-friendly way for the structural modification of polysaccharides,which helps to enhance their biological activity and promote their wide application in food,medicine and other fields.展开更多
This paper delves into the critical aspects of sheet pile walls in civil engineering, highlighting their versatility in soil protection, retention, and waterproofing, all while emphasizing sustainability and efficient...This paper delves into the critical aspects of sheet pile walls in civil engineering, highlighting their versatility in soil protection, retention, and waterproofing, all while emphasizing sustainability and efficient construction practices. The paper explores two fundamental approaches to sheet pile design: limit equilibrium methods and numerical techniques, with a particular focus on finite element analysis. Utilizing the robust PLAXIS 2016 calculation code based on the finite element method and employing a simplified elastoplastic model (Mohr-Coulomb), this study meticulously models the interaction between sheet pile walls and surrounding soil. The research offers valuable insights into settlement and deformation patterns that adjacent buildings may experience during various construction phases. The central objective of this paper is to present the study’s findings and recommend potential mitigation measures for settlement effects on nearby structures. By unraveling the intricate interplay between sheet pile wall construction and neighboring buildings, the paper equips engineers and practitioners to make informed decisions that ensure the safety and integrity of the built environment. In the context of the Cotonou East Corniche development, the study addresses the limitations of existing software, such as RIDO, in predicting settlements and deformations affecting nearby buildings due to the substantial load supported by sheet pile walls. This information gap necessitates a comprehensive study to assess potential impacts on adjacent structures and propose suitable mitigation measures. The research underscores the intricate dynamics between sheet pile wall construction and its influence on the local environment. It emphasizes the critical importance of proactive engineering and vigilant monitoring in managing and mitigating potential hazards to nearby buildings. To mitigate these risks, the paper recommends measures such as deep foundations, ground improvement techniques, and retrofitting. The findings presented in this study contribute significantly to the field of civil engineering and offer invaluable insights into the multifaceted dynamics of construction-induced settlement. The study underscores the importance of continuous evaluation and coordination between construction teams and building owners to effectively manage the impacts of sheet pile wall construction on adjacent structures.展开更多
The West Junggar Orogenic Belt(WJOB)in northwestern Xinjiang,China,is located in the core of the western part of the Central Asian Orogenic Belt(CAOB).It has suffered two stage tectonic evolutions in Phanerozoic,befor...The West Junggar Orogenic Belt(WJOB)in northwestern Xinjiang,China,is located in the core of the western part of the Central Asian Orogenic Belt(CAOB).It has suffered two stage tectonic evolutions in Phanerozoic,before and after the ocean–continental conversion in Late Paleozoic.The later on intracontinental deformation,characterized by the development of the NE-trending West Junggar sinistral strike-slip fault system(WJFS)since Late Carboniferous and Early Permian,and the NW-trending Chingiz-Junggar dextral strike-slip fault(CJF)in Mesozoic and Cenozoic,has an important significance for the tectonic evolution of the WJOB and the CAOB.In this paper,we conduct geometric and kinematic analyses of the WJOB,based on field geological survey and structural interpretation of remote sensing image data.Using some piercing points such as truncated plutons and anticlines,an average magnitude of^73 km for the left-lateral strike-slip is calculated for the Darabut Fault,a major fault of the WJFS.Some partial of the displacement should be accommodated by strike-slip fault-related folds developed during the strike-slip faulting.Circular and curved faults,asymmetrical folds,and irregular contribution of ultramafic bodies,implies potential opposite vertical rotation of the Miao’ergou and the Akebasitao batholiths,resulted from the sinistral strike-slipping along the Darabut Fault.Due to conjugate shearing set of the sinistral WJFS and the dextral CJF since Early Mesozoic,superimposed folds formed with N–S convergence in southwestern part of the WJOB.展开更多
The Makran represents a huge accretionary wedge in SE Iran that resulted from the long-lasting subduction of the Neotethys Ocean since the Mesozoic. From west to east, this accretionary wedge extends ~1000 km between ...The Makran represents a huge accretionary wedge in SE Iran that resulted from the long-lasting subduction of the Neotethys Ocean since the Mesozoic. From west to east, this accretionary wedge extends ~1000 km between the Minab Fault in Iran, and the Ornach-Nal Fault in Pakistan. The ongoing oceanic subduction characterizes this belt between the Iranian Plateau and the Tibetan Plateau, both of which were generated by collision of Eurasian with the Arabian and Indian plates, and provides an ideal target to recover the tectonic history of subduction. The western Makran located in Iran can be subdivided into four units: The North Makran ophiolitic mélange, the Inner Makran, the Outer Makran, and the Coastal Makran. Based on our detailed structural analysis and geochronological dating, we obtain several new results that can help us to better understand the structural evolution:(1) The North Makran ophiolitic mélange includes thick piles of volcanic rocks and limestone that directly cover the mantle peridotite, so it is likely to be part of an Early Cretaceous volcanic arc by our zircon dating at ~115 Ma on mafic intrusions;(2) The entire western Makran underwent three phases of deformation. D1 is characterized by top-to-the S/SW thrusting as evidence by southward emplacement of the ophiolitic mélange onto the Eocene sedimentary rocks. D2 deformation strongly folded the pre-late Miocene/early Pliocene strata that also corresponds to the final emplacement of the ophiolite to the surface. D3 structures extends in a N-S direction with top-to-the W kinematics that overthrust the Miocene sandstone onto the Pliocene fluvial sediments along the Minab Fault;(3) Combined with geological and geochronological relationship, D1 occurred at ~45-35 Ma, D2 initiated in middle Miocene and ended with a regional late Miocene-early Pliocene uncomformity, and D3 structures are still active as the subduction continues.展开更多
At present,there is not much research on mid-story isolated structures in mountainous areas.In this study,a model of a mid-story isolated structure considering soil-structure interaction(SSI)in mountainous areas is es...At present,there is not much research on mid-story isolated structures in mountainous areas.In this study,a model of a mid-story isolated structure considering soil-structure interaction(SSI)in mountainous areas is established along with a model that does not consider SSI.Eight long-period earthquake waves and two ordinary earthquake waves are selected as inputs for the dynamic time history analysis of the structure.The results show that the seismic response of a mid-story isolated structure considering SSI in mountainous areas can be amplified when compared with a structure that does not consider SSI.The structure response under long-period earthquakes is larger than that of ordinary earthquakes.The structure response under far-field harmonic-like earthquakes is larger than that of near-fault pulse-type earthquakes.The structure response under near-fault pulse-type earthquakes is larger than that of far-field non-harmonic earthquakes.When subjected to long-period earthquakes,the displacement of the isolated bearings exceeded the limit value,which led to instability and overturning of the structure.The structure with dampers in the isolated story could adequately control the nonlinear response of the structure,effectively reduce the displacement of the isolated bearings,and provide a convenient,efficient and economic method not only for new construction but also to retrofit existing structures.展开更多
In architecture,interlace structural concept is considered as a new design approach for cosmopolitan cities with high density to minimize the land use and increase the interaction.With various architectural approach,l...In architecture,interlace structural concept is considered as a new design approach for cosmopolitan cities with high density to minimize the land use and increase the interaction.With various architectural approach,land resources can be minimized by this interlace concept for residential complexes.Such buildings will eliminate the reduction of land resource problem and on the other side safety measures in structural design is incorporated by interlace concept of buildings.This new concept can be constructed steel or reinforced concrete.In this paper,an analytical approach has been presented for these buildings in architecture and structural design.In the research,design considerations were taken for interlaced structures with reinforced concrete and steel.Components of steel structure,isolated footing,and columns.This paper is presenting a step wise process for interlaced structures.They are identification of project area,layout and model preparation,analysis and design of concrete interlaced structure,analysis and design of steel interlaced structure,drafting of the plans and costing and estimation of the structures.Comparison of both reinforced concrete and steel structures were carried out.The main aim of the paper is to provide a comparison between steel and concrete interlaced structure.A cost estimation was carried out to determine optimum design and construction for interlaced structures.展开更多
Floors subjected to mechanical equipment loads frequently present problems associated with excessive vibration which can cause human discomfort or even reduce the structure service life.In this context,this work aims ...Floors subjected to mechanical equipment loads frequently present problems associated with excessive vibration which can cause human discomfort or even reduce the structure service life.In this context,this work aims to develop an analysis methodology in order to assess the fatigue performance of steel-concrete composite floors,when subjected to vibrations induced by mechanical equipment.The studied structural model corresponds to a steel-concrete composite floor spanning 10 m by 10 m,with a total area of 100 m^(2).The numerical model developed for the dynamic analysis adopted the usual mesh refinement techniques present in finite element method(FEM)simulations implemented in the ANSYS program.The investigated floor dynamic response was calculated through the consideration of the dynamic loadings imposed by the mechanical equipment,simulated based on the use of harmonic forces applied on the concrete slabs.Furthermore,the dynamic structural response was performed considering several scenarios for the positioning of the equipment,in order to verify the occurrence of excessive vibration.The fatigue assessment is based on a linear cumulative damage rule through the use of the Rainflow-counting algorithm and S-N curves from traditional design codes.The results of this investigation indicated that the equipment position affects directly the floor dynamic structural response and also significantly influences the structure service life.展开更多
基金financially supported by the China Geological Survey(Grant Nos.DD20230229,DD20160083,DD20190011,DD20221643-5)the National Key Research and Development Program of China(the DREAM—Deep Resource Exploration and Advanced Mining+1 种基金Grant No.2018YFC0603701)the Cooperative Project between the Chinese Academy of Geological Sciences and the Sinopec Shengli Oilfield Company(Grant No.P22065)。
文摘The North Qilian Shan fold and thrust belt,located at the northern Tibetan Plateau and southern margin of the Hexi Corridor,is a key tectonic unit to decode the formation and expansion of the plateau.Previous studies emphasize the Cenozoic deformation due to the far-field response to the Indo-Asian collision,but the Mesozoic deformations are poorly constrained in this area.We conducted detailed field mapping,structural analysis,geochronology,and structural interpretation of deep seismic reflectional profiling and magnetotelluric(MT)sounding,to address the superposed results of the Mesozoic and Cenozoic deformation.The results recognized the North Qilian thrust and nappe system(NQTS),the root and the frontal belt are the North Qilian thrust(NQT),and the Yumu Shan klippe(YK),respectively.The middle belt is located between the NQT and the YK.Monzonitic granite zircon U-Pb dating from the middle belt yields an age of ca.415 Ma,which is similar to south NQT.The thrusting displacement is estimated at ca.48 km by structural interpretation of deep profiles.The timing is constrained in the early stage of the Early Cretaceous by the formation of simultaneous growth strata.We suggest that the NQTS has resulted from the far-field effect of the Lhasa-Qiangtang collision,and the Yumu Shan is uplifted by the superposed Cenozoic deformation.
文摘Purpose of present work is to develop a reliable and simple method for structural analysis of RC Shear Walls. The shear wall is simulated by a truss model as the bar of a truss is the simplest finite element. An iterative method is used. Initially, there are only concrete bars. Repeated structural analyses are performed. After each structural analysis, every concrete bar exceeding tensile strength is replaced by a steel bar. For every concrete bar exceeding compressive strength, first its section area is increased. If this is not enough, a steel bar is placed at the side of it. For every steel bar exceeding tensile or compressive strength, its section area is increased. After the end of every structural analysis, if all concrete and steel bars fall within tensile and compressive strengths, the output data are written and the analysis is terminated. Otherwise, the structural analysis is repeated. As all the necessary conditions (static, elastic, linearized geometric) are satisfied and the stresses of ALL concrete and steel bars fall within the tensile and compressive strengths, the results are acceptable. Usually, the proposed method exhibits a fast convergence in 4 - 5 repeats of structural analysis of the RC Shear Wall.
文摘This paper introduces a new version of the open-source educational software, LESM (Linear Elements Structure Model), developed in MATLAB for structural analysis of one-dimensional models such as frames, trusses, and grillages. The updated program includes dynamic analysis, which incorporates inertial and damping effects, time-dependent load conditions, and a transient solver with multiple time integration schemes. The software assumes small displacements and linear-elastic material behavior. The paper briefly explains the theoretical basis for these developments and the reorganization of the source code using Object-Oriented Programming (OOP). The updated Graphical User Interface (GUI) allows interactive use of dynamic analysis features and displays new results such as animations, envelope diagrams of internal forces, phase portraits, and the response of degrees-of-freedom in time and frequency domain. The new version was used in a structural dynamics course, and new assignments were elaborated to improve students’ understanding of the subject.
基金the National Natural Science Foundation of China(21975154)the Shanghai Municipal Education Commission(Innovation Program(2019-01-07-00-09E00021)+2 种基金Innovative Research Team of High-level Local Universities in Shanghaisupported by The Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher LearningShanghai Key Laboratory of Materials Protection and Advanced Materials in Electric Power。
文摘With great superiorities in energy density,rate capability and structural stability,Na_(3)V_(2)(PO_(4))_(2) F_(3)(NVPF)has attracted much attentions as cathode of sodium ion battery(SIB),but it also faces challenges on its poor intrinsic electronic conductivity and the controversial de/sodiation mechanism.Herein,a series of Zr-doped NVPF coated by N-doped carbon layer(~5 nm in thickness,homogenously)materials are fabricated by a sol-gel method,and the optimized heteroatom-doping amounts of Zr and N doping improve intrinsic properties on enlarging lattice distance and enhancing electronic conductivity,respectively.Specifically,among all samples of Na_(3) V_(2-x)Zr_(x)(PO_(4))_(2) F_(3)/NC(NVPF-Zr-x/NC,x=0,0.01,0.02,0.05,and 0.1),the optimized electrode of NVPF-Zr-0.02/NC delivers high reversible capacities(119.2 mAh g^(-1) at0.5 C),superior rate capability(98.1 mA h g^(-1) at 20 C)and excellent cycling performance.The structural evolution of NVPF-Zr-0.02/NC electrode,in-situ monitored by X-ray diffractometer,follows a step-wise Na-extraction/intercalation mechanism with reversible multi-phase changes,not just a solid-solutionreaction one.Full cells of NVPF-Zr-0.02/NC//hard carbon demonstrate high capacity(99.8 mA h g^(-1) at 0.5 C),high out-put voltage(3.5 V)and good cycling stability.This work is favorable to accelerate the development of high-performance cathode materials and explore possible redox reaction mechanisms of SIBs.
文摘A better understanding of the relationship between the structure and functions of urban and suburban spaces is one of the avenues of research still open for geographical information science.The research presented in this paper develops several graph-based metrics whose objective is to characterize some local and global structural properties that reflect the way the overall building layout can be cross-related to the one of the road layout.Such structural properties are modeled as an aggregation of parcels,buildings,and road networks.We introduce several computational measures(Ratio Minimum Distance,Minimum Ratio Minimum Distance,and Metric Compactness)that respectively evaluate the capability for a given road to be connected with the whole road network.These measures reveal emerging sub-network structures and point out differences between less-connective and moreconnective parts of the network.Based on these local and global properties derived from the topological and graph-based representation,and on building density metrics,this paper proposes an analysis of road and building layouts at different levels of granularity.The metrics developed are applied to a case study in which the derived properties reveal coherent as well as incoherent neighborhoods that illustrate the potential of the approach and the way buildings and roads can be relatively connected in a given urban environment.Overall,and by integrating the parcels and buildings layouts,this approach complements other previous and related works that mainly retain the configurational structure of the urban network as well as morphological studies whose focus is generally limited to the analysis of the building layout.
基金funded by the Key Research and Development Program of the Ningxia Hui Autonomous Region(2021BEF02011)the CAS“Light of West China”Program.
文摘The water-soluble polysaccharide LBP-1 was isolated and characterized from Lycium barbarum L.LBP-1 was mainly composed of arabinose,galactose,glucose,xylose,mannose at a molar ratio of 37.53:28.08:14.72:7.83:4.50,respectively.Based on nuclear magnetic resonance(NMR)and methylation analysis,the backbone of LBP-1 was speculated in theα-L-Ara(1→[5-α-L-Ara(1→3)-β-D-Galp-(1→]n→4)-α-D-Galp-(1[→5-α-L-Ara(1]n[→6)-β-D-Galp-(1→4)-β-D-Galp-(1→]n,and the side chains of LBP-1 were in theα-L-Ara(1→3)-β-D-Galp-(1→6 position.These results showed that LBP-1 inhibited the growth of cancer A549 cells through cell cycle arrest and apoptosis,with an IC50 value of 42.5μg/mL.In addition,LBP-1 altered the expression of Cyclin D1,Cyclin D3,and CDK 2,thus blocking the cell cycle in G0/G1 phase,reducing cell migration,and regulating the PI3K/Akt/mTOR signaling pathway to induce apoptosis.
基金supported by the National Basic Research Program of China(2011CB302402)the National Natural Science Foundation of China(Grant Nos.91118001,11171053)+1 种基金the West Light Foundation of the Chinese Academy of Sciences,China Postdoctoral Science Foundation Funded Project(Grant No.2012M521692)the Chinese Academy of Sciences Visiting Professorship for Senior International Scientists(Grant No.2010T2G31)。
文摘This paper deals with the structural analysis problem of dynamic lumped process high-index differential algebraic equations(DAE)models.The existing graph theoretical method depends on the change in the relative position of underspecified and overspecified subgraphs and has an effect to the value of the differential index for complex models.In this paper,we consider two methods for index reduction of such models by differentiation:Pryce’s method and the symbolic differential elimination algorithm rifsimp.They can remedy the above drawbacks.Discussion and comparison of these methods are given via a class of fundamental process simulation examples.In particular,the efficiency of Pryce’s method is illustrated as a function of the number of tanks in process design.Moreover,a range of nontrivial problems are demonstrated by the symbolic differential elimination algorithm and fast prolongation.
基金The authors acknowledge Eric R.Kent and Jizhang Wang for assistance with editing the manuscript.This work was supported by Six Talent Peaks Program in Jiangsu Province(2015-ZBZZ-021)Key R&D Program of Jiangsu Province(BE2016354)Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘Quantitative analysis on cutting notch of tea stalk is one method to better understand shear resistance and mechanical properties of the stalk,which could improve cutting performance and efficiency for tea harvesting.Optimal design of the cutter might be achieved through structural analysis of cutting notch by X-ray micro-computed tomography(micro-CT).The third inter-node of the stalks were sampled and scanned by micro-CT after they were cut at different cutting depths(0.7,1.5,2.3 mm)and cutting edge angles of cutter(30,35,40).The structural change of the cutting notch and cutting force was observed.Grey-scale histogram analysis and bimodal segmentation method were used to extract the information about cutting notch from 2D slice images.A 3D model of the stalk was established with reconstruction and volume rendering.Besides,maximum crosssectional area ratio of cutting notch(MCSARCN)and volume ratio of cutting notch(VRCN)were calculated.The results show that MCSARCN and VRCN had a closely relationship with the cutting force,cutting depth and cutting edge angle according to 3D tomographic images and 2D slice images.Both MCSARCN and VRCN increased with cutting depth,despite of cutting edge angle.For cutting edge angle of 30,35and 40at different cutting depths,MCSARCN increased from 4.89%to 9.47%,from 8.51%to 22.83%and from 4.30%to 16.87%,respectively.Meanwhile,VRCN increased from 1.59%to 2.13%,from 2.98%to 5.76%and from 3.04%to 5.01%,respectively.When cutting depth was 1.5 mm,cutting force increased but VRCN present a decreased trend with cutting edge angle.X-ray micro-CT could be used to analyze the structure on cutting notch of tea stalks which is helpful in optimizing the structural parameters of the cutter.
文摘Structural analysis problems can be formulized as either root finding problems,or optimization problems.The general practice is to choose the first option directly or to convert the second option again to a root finding problem by taking relevant derivatives and equating them to zero.The second alternative is used very randomly as it is and only for some simple demonstrative problems,most probably due to difficulty in solving optimization problems by classical methods.The method called TPO/MA(Total Potential Optimization using Metaheuristic Algorithms)described in this study successfully enables to handle structural problems with optimization formulation.Using metaheuristic algorithms provides additional advantages in dealing with all kinds of constraints.
文摘The suspension coil spring is one of the most important components in a vehicle suspension system. Its primary function is to absorb the vibrational shocks that are occasioned by irregular road surface to provide the vehicle with stability and ride comfort. The main objective of this study is to design a suspension coil spring made of structural steel for light duty vehicles with the aim of weight and cost reduction. This study was motivated by the government of Ghana’s actions to industrialise the automotive sector of the country through government policies and programs. The study made use of high carbon steel and low carbon steel as the control materials and structural steel as the implementing material. This was done to determine the suitability of structural steel for vehicle suspension coil spring. The study analysed parameters such as total deformation, equivalent Von Mises stress, maximum shear stress, and safety factor in the static structural analysis. The fatigue analysis also analysed parameters such as fatigue life and fatigue alternating stress. The results of the study revealed that the suspension spring made of structural steel has superior properties against all the parameters set for this study apart from deformation. The two control materials that are known for suspension coil spring design and manufacture have better properties to withstand deformation than the implementing material.
基金Project(2012GK2025)supported by Science-Technology Plan Foundation of Hunan Province,ChinaProject(2013zzts039)supported by the Fundamental Research Funds for Central South University,China
文摘A hierarchical structural decomposition analysis(SDA) model has been developed based on process-level input-output(I-O) tables to analyze the drivers of energy consumption changes in an integrated steel plant during 2011-2013. By combining the principle of hierarchical decomposition into D&L method, a hierarchical decomposition model for multilevel SDA is obtained. The developed hierarchical IO-SDA model would provide consistent results and need less computation effort compared with the traditional SDA model. The decomposition results of the steel plant suggest that the technology improvement and reduced steel final demand are two major reasons for declined total energy consumption. The technical improvements of blast furnaces, basic oxygen furnaces, the power plant and the by-products utilization level have contributed mostly in reducing energy consumption. A major retrofit of ancillary process units and solving fuel substitution problem in the sinter plant and blast furnace are important for further energy saving. Besides the empirical results, this work also discussed that why and how hierarchical SDA can be applied in a process-level decomposition analysis of aggregated indicators.
文摘In this paper, the fuzzy-set-based structural possibility theory is investigated, and this theory can be used to deal with the subjective uncertainties in the design of engineering structures. Furthermore, a comprehensive model of structural safety assessment, which can merge subjective uncertainties with objective uncertainties, is presented. In this model, the fuzziness of stress-strength inference model, safety margin functions of single or multiple limit-state, structural failure state and the final assessment result are taken into account. This continuous model can be transformed into an equivalent model of probability-based and solved by the present structural reliability analysis method and parallel algorithm. An example is given to show the main idea of the method presented in this paper.
基金This research receives funding from the Maryland Department of Transportation State Highway Administration.
文摘This paper studies the deterioration of bridge substructures utilizing the Long-Term Bridge Performance(LTBP)Program InfoBridge^(TM)and develops a survival model using Cox proportional hazards regression.The survival analysis is based on the National Bridge Inventory(NBI)dataset.The study calculates the survival rate of reinforced and prestressed concrete piles on bridges under marine conditions over a 29-year span(from 1992 to 2020).The state of Maryland is the primary focus of this study,with data from three neighboring regions,the District of Columbia,Virginia,and Delaware to expand the sample size.The data obtained from the National Bridge Inventory are condensed and filtered to acquire the most relevant information for model development.The Cox proportional hazards regression is applied to the condensed NBI data with six parameters:Age,ADT,ADTT,number of spans,span length,and structural length.Two survival models are generated for the bridge substructures:Reinforced and prestressed concrete piles in Maryland and reinforced and prestressed concrete piles in wet service conditions in the District of Columbia,Maryland,Delaware,and Virginia.Results from the Cox proportional hazards regression are used to construct Markov chains to demonstrate the sequence of the deterioration of bridge substructures.The Markov chains can be used as a tool to assist in the prediction and decision-making for repair,rehabilitation,and replacement of bridge piles.Based on the numerical model,the Pile Assessment Matrix Program(PAM)is developed to facilitate the assessment and maintenance of current bridge structures.The program integrates the NBI database with the inspection and research reports from various states’department of transportation,to serve as a tool for condition state simulation based on maintenance or rehabilitation strategies.
基金supported by grants from the National Key R&D Program of China(2019YFC1606701)。
文摘Plant-based fermentations provide an untapped source for novel biotechnological applications.In this study,a probiotic named Lactobacillus fermentum 21828 was introduced to ferment Lentinus edodes.Polysaccharides were extracted from fermented and non-fermented L.edodes and purified via DEAE-52 and Sephadex G-100.The components designated F-LEP-2a and NF-LEP-2a were analyzed by FT-IR,HPGPC,HPAEC,SEM,GC-MS and NMR.The results revealed that probiotic fermentation increased the molecular weight from 1.16×10^(4) Da to 1.87×10^(4) Da and altered the proportions of glucose,galactose and mannose,in which glucose increased from 45.94%to 48.16%.Methylation analysis and NMR spectra indicated that F-LEP-2a and NF-LEP-2a had similar linkage patterns.Furthermore,their immunomodulatory activities were evaluated with immunosuppressive mice.NF-LEP and F-LEP improved immune organ indices,immunoglobulin(Ig G and Ig M)and cytokines concentrations;restored the antioxidation capacity of liver;and maintained the balance of gut microbiota.F-LEP displayed better moderating effects on the spleen index,immunoglobulin,cytokines and the diversity of gut microbiota than NF-LEP(200,400 mg/kg).Our study provides an efficient and environment-friendly way for the structural modification of polysaccharides,which helps to enhance their biological activity and promote their wide application in food,medicine and other fields.
文摘This paper delves into the critical aspects of sheet pile walls in civil engineering, highlighting their versatility in soil protection, retention, and waterproofing, all while emphasizing sustainability and efficient construction practices. The paper explores two fundamental approaches to sheet pile design: limit equilibrium methods and numerical techniques, with a particular focus on finite element analysis. Utilizing the robust PLAXIS 2016 calculation code based on the finite element method and employing a simplified elastoplastic model (Mohr-Coulomb), this study meticulously models the interaction between sheet pile walls and surrounding soil. The research offers valuable insights into settlement and deformation patterns that adjacent buildings may experience during various construction phases. The central objective of this paper is to present the study’s findings and recommend potential mitigation measures for settlement effects on nearby structures. By unraveling the intricate interplay between sheet pile wall construction and neighboring buildings, the paper equips engineers and practitioners to make informed decisions that ensure the safety and integrity of the built environment. In the context of the Cotonou East Corniche development, the study addresses the limitations of existing software, such as RIDO, in predicting settlements and deformations affecting nearby buildings due to the substantial load supported by sheet pile walls. This information gap necessitates a comprehensive study to assess potential impacts on adjacent structures and propose suitable mitigation measures. The research underscores the intricate dynamics between sheet pile wall construction and its influence on the local environment. It emphasizes the critical importance of proactive engineering and vigilant monitoring in managing and mitigating potential hazards to nearby buildings. To mitigate these risks, the paper recommends measures such as deep foundations, ground improvement techniques, and retrofitting. The findings presented in this study contribute significantly to the field of civil engineering and offer invaluable insights into the multifaceted dynamics of construction-induced settlement. The study underscores the importance of continuous evaluation and coordination between construction teams and building owners to effectively manage the impacts of sheet pile wall construction on adjacent structures.
基金supported by the China Geological Survey (Grant Nos. DD20160083, DD20160344-05)the Chinese Academy of Geological Sciences Research Fund (Grant No. CAGS-YWF201706)
文摘The West Junggar Orogenic Belt(WJOB)in northwestern Xinjiang,China,is located in the core of the western part of the Central Asian Orogenic Belt(CAOB).It has suffered two stage tectonic evolutions in Phanerozoic,before and after the ocean–continental conversion in Late Paleozoic.The later on intracontinental deformation,characterized by the development of the NE-trending West Junggar sinistral strike-slip fault system(WJFS)since Late Carboniferous and Early Permian,and the NW-trending Chingiz-Junggar dextral strike-slip fault(CJF)in Mesozoic and Cenozoic,has an important significance for the tectonic evolution of the WJOB and the CAOB.In this paper,we conduct geometric and kinematic analyses of the WJOB,based on field geological survey and structural interpretation of remote sensing image data.Using some piercing points such as truncated plutons and anticlines,an average magnitude of^73 km for the left-lateral strike-slip is calculated for the Darabut Fault,a major fault of the WJFS.Some partial of the displacement should be accommodated by strike-slip fault-related folds developed during the strike-slip faulting.Circular and curved faults,asymmetrical folds,and irregular contribution of ultramafic bodies,implies potential opposite vertical rotation of the Miao’ergou and the Akebasitao batholiths,resulted from the sinistral strike-slipping along the Darabut Fault.Due to conjugate shearing set of the sinistral WJFS and the dextral CJF since Early Mesozoic,superimposed folds formed with N–S convergence in southwestern part of the WJOB.
基金granted by the National Natural Science Foundation of China(91855103,91855207 and 91855212)the Ministry of Science and Technology(2016YFC0600401 and 2016YFC0600102)the State Key Laboratory of Lithospheric Evolution(SKL-Q201801)
文摘The Makran represents a huge accretionary wedge in SE Iran that resulted from the long-lasting subduction of the Neotethys Ocean since the Mesozoic. From west to east, this accretionary wedge extends ~1000 km between the Minab Fault in Iran, and the Ornach-Nal Fault in Pakistan. The ongoing oceanic subduction characterizes this belt between the Iranian Plateau and the Tibetan Plateau, both of which were generated by collision of Eurasian with the Arabian and Indian plates, and provides an ideal target to recover the tectonic history of subduction. The western Makran located in Iran can be subdivided into four units: The North Makran ophiolitic mélange, the Inner Makran, the Outer Makran, and the Coastal Makran. Based on our detailed structural analysis and geochronological dating, we obtain several new results that can help us to better understand the structural evolution:(1) The North Makran ophiolitic mélange includes thick piles of volcanic rocks and limestone that directly cover the mantle peridotite, so it is likely to be part of an Early Cretaceous volcanic arc by our zircon dating at ~115 Ma on mafic intrusions;(2) The entire western Makran underwent three phases of deformation. D1 is characterized by top-to-the S/SW thrusting as evidence by southward emplacement of the ophiolitic mélange onto the Eocene sedimentary rocks. D2 deformation strongly folded the pre-late Miocene/early Pliocene strata that also corresponds to the final emplacement of the ophiolite to the surface. D3 structures extends in a N-S direction with top-to-the W kinematics that overthrust the Miocene sandstone onto the Pliocene fluvial sediments along the Minab Fault;(3) Combined with geological and geochronological relationship, D1 occurred at ~45-35 Ma, D2 initiated in middle Miocene and ended with a regional late Miocene-early Pliocene uncomformity, and D3 structures are still active as the subduction continues.
基金National Natural Science Fund of China under Nos.52168072 and 51808467High-level Talents Support Plan of Yunnan Province of China(2020)。
文摘At present,there is not much research on mid-story isolated structures in mountainous areas.In this study,a model of a mid-story isolated structure considering soil-structure interaction(SSI)in mountainous areas is established along with a model that does not consider SSI.Eight long-period earthquake waves and two ordinary earthquake waves are selected as inputs for the dynamic time history analysis of the structure.The results show that the seismic response of a mid-story isolated structure considering SSI in mountainous areas can be amplified when compared with a structure that does not consider SSI.The structure response under long-period earthquakes is larger than that of ordinary earthquakes.The structure response under far-field harmonic-like earthquakes is larger than that of near-fault pulse-type earthquakes.The structure response under near-fault pulse-type earthquakes is larger than that of far-field non-harmonic earthquakes.When subjected to long-period earthquakes,the displacement of the isolated bearings exceeded the limit value,which led to instability and overturning of the structure.The structure with dampers in the isolated story could adequately control the nonlinear response of the structure,effectively reduce the displacement of the isolated bearings,and provide a convenient,efficient and economic method not only for new construction but also to retrofit existing structures.
文摘In architecture,interlace structural concept is considered as a new design approach for cosmopolitan cities with high density to minimize the land use and increase the interaction.With various architectural approach,land resources can be minimized by this interlace concept for residential complexes.Such buildings will eliminate the reduction of land resource problem and on the other side safety measures in structural design is incorporated by interlace concept of buildings.This new concept can be constructed steel or reinforced concrete.In this paper,an analytical approach has been presented for these buildings in architecture and structural design.In the research,design considerations were taken for interlaced structures with reinforced concrete and steel.Components of steel structure,isolated footing,and columns.This paper is presenting a step wise process for interlaced structures.They are identification of project area,layout and model preparation,analysis and design of concrete interlaced structure,analysis and design of steel interlaced structure,drafting of the plans and costing and estimation of the structures.Comparison of both reinforced concrete and steel structures were carried out.The main aim of the paper is to provide a comparison between steel and concrete interlaced structure.A cost estimation was carried out to determine optimum design and construction for interlaced structures.
基金the support for this work provided by the Brazilian Science Foundations:CAPES,CNPq and FAPERJ.
文摘Floors subjected to mechanical equipment loads frequently present problems associated with excessive vibration which can cause human discomfort or even reduce the structure service life.In this context,this work aims to develop an analysis methodology in order to assess the fatigue performance of steel-concrete composite floors,when subjected to vibrations induced by mechanical equipment.The studied structural model corresponds to a steel-concrete composite floor spanning 10 m by 10 m,with a total area of 100 m^(2).The numerical model developed for the dynamic analysis adopted the usual mesh refinement techniques present in finite element method(FEM)simulations implemented in the ANSYS program.The investigated floor dynamic response was calculated through the consideration of the dynamic loadings imposed by the mechanical equipment,simulated based on the use of harmonic forces applied on the concrete slabs.Furthermore,the dynamic structural response was performed considering several scenarios for the positioning of the equipment,in order to verify the occurrence of excessive vibration.The fatigue assessment is based on a linear cumulative damage rule through the use of the Rainflow-counting algorithm and S-N curves from traditional design codes.The results of this investigation indicated that the equipment position affects directly the floor dynamic structural response and also significantly influences the structure service life.
