最新刊期
卷 31 ， 期 2 ， 2009
- 摘要：The tubegusset plate connections are widely used in electric transmission towers. However, there is little technical information regarding the behavior of tubegusset plate connections. Thus, a analytical parametric study was conducted to investigate the behavior of tubegusset plate connections. The analytical results were compared with the existing experimental results. It was found that the finite element analysis results were in good agreement with the experimental results. In the parametric study, the effects of geometry, chord load and stiffener on the ultimate strength were considered. Based on the analytical results, a design method for predicting the ultimate strength of tubegusset connections was proposed, and its applicability was verified.9836|1281|0更新时间：2023-11-28
- 摘要：In order to solve the calculation problems of the curved beam, an arbitrary crosssection beam and composite beam, a degenerated 3D fiber beam element is derived based on the degenerated theory. According to the basic assumption of plane section, the 3D displacement field equations of an arbitrary point are discretized in terms of nodal displacements, which take account of shear deformation effect. Furthermore, the tangent stiffness matrix formulation, which takes geometric and material nonlinearity into account, is deduced using Update Lagrange formulation. A finite element method program has been developed, and several typical examples are tested to demonstrate the effectiveness, accuracy and versatility of this beam element.10559|1084|0更新时间：2023-11-28
- 摘要：By the methods of microdamage theory, the relations of rock mass parameters and rock parameters in experiments were obtained; it is considered that to make the microdamage theory for determining the rock parameters possible only in condition that the crack density parameters are obtained reasonably. The methods to determine rock mass crack density have been set up through the intactness index of rock mass and elastic wave equation as well as the geological investigating statistical method, The differences of rock crack density given by these three methods were discussed; based on the statistical data, the Taylor method and generalized selfconsistent method and the Taylor medium method were compared in respect of the influence of crack interaction and the adaptability to the rock parameters . The results show that the reasonable results can be obtained by determining rock crack density from intactness index of rock mass and rock mass parameters by the Taylor medium method.2801|1830|0更新时间：2023-11-28
- 摘要：This paper explored bending performance of tubegusset joint primarily according to experiment and finite element model. The method which is used to determine ultimate strength of the joint was proposed on the base of three joint types including /4 circle ribbed, half circle ribbed and circle ribbed stiffeners. Compared with the Japanese electricity transmitting steel tubular tower manufacture norm, a conclusion has been drawn that the ultimate strength has relationship with several different parameters. The result shows that the ultimate strength of the joint is related not only to the wall thickness t, diameter D, length of gusset plate B and the yield deflection δ at the top of the relevant section under the current status of the region, but also to the ribbed plate. The formula about ultimate strength has important application value for engineering design.3873|408|1更新时间：2023-11-28
- 摘要：The manufacturing deviation of grids structures was assumed to be in normal distribution, and the normal random sampling was realized by acceptancerejection method. Based on the finite element method and probability method, the initial displacement and stress of grids structures due to manufacturing deviation were analyzed. Numerical example showed that the random manufacturing deviation produced large initial stress, which induced buckling failure of some spatial grid members, and had a large effect on the safety of the grids structures and could not be ignored. It also showed that the method obtained had guiding significance for the design and fabrication of grids structures.3357|344|1更新时间：2023-11-28
- 摘要：Taking the temperature effect and geometric nonlinearity into consideration, the nonlinear vibration equation of monolayer cable net for pointsupported curtain wall was derived by assuming the net as a continuum membra. By the Galerkin method, the partial differential equation was transformed into ordinary differential equation which was solved with LP method and KBM method. Taking the monolayer cable net for pointsupported curtain wall of Zhongguancun Culture Building as an example, the effects of temperature, amplitude, initial displacement and exterior excitation on the nonlinear vibration were discussed. The example indicates that the temperature has great influence on the nonlinear vibration of monolayer cable net and the vibration of monolayer cable net for pointsupported curtain wall shows a hard spring characteristic.3030|449|1更新时间：2023-11-28
- 摘要：To set up a mechanical model of threepoint loading for the intellectual measuring equipment of cable tension, the cases for elastic support with two ends of hinged support and those of fixed support with consideration of the influence of the cable were systematically studied. The equations for the upper and lower limits of the cable tension T as well as those for the real measured values have been obtained. A more rational equation for online measuring the cable tension by “Threepoint Bending Method” has been derived through secondary measurement.4299|1953|1更新时间：2023-11-28
- 摘要：Referring to the criterion of seismic fortification intensity 8 specified by national seismic design code, a /2scaled model of single span and twostory frame composed of RC beams and Tshaped steel reinforced concrete (SRC) columns has been made. A seismic evaluation was performed by the quasistatic testing, including failure pattern, stiffness degradation, ductility and energy dissipation. The experimental results show that the frame has good seismic behavior, and section steel in the columns plays an important role in earthquake resistance. On the basis of experimental study and analysis, it concludes that the seismic behavior of frame with SRC specialshaped columns can satisfy the requirements of seismic fortification. 3100|1433|19更新时间：2023-11-28
- 摘要：Based on the equilibrium of static forces and coordination of deformations, with considering the effects of bond strength variation and crack width development at different stress stage of reinforcement in tension cracks, the average stress strain relationship of unanchored zone of RC structure under bond and slip action has been derived. The typical test on reinforced concrete beams was simulated with average constitutional relationship and the result was compared with that of real test. The analytical results show that the model using average constitutional relationship with considering bond and slip in unanchored zone of RC structure can give a result close to that of test and simplify the nonlinear analysis.2974|1820|3更新时间：2023-11-28
- 摘要：In order to put the Internal Stretch Forming Space Lattice Structure (ISFSL) into practice, based on the Geometrical Displacementiterative Method, the Displacementiteration Formfinding Arithmetic in R Coordinates is proposed，in which only the displacementiteration is exerted on span coordinates of ISFSL. A detailed study on the formfinding process is carried out, which is based on an ISFSL with a long span of 80m. The result shows that this arithmetic is very simple with great efficiency and working speed. When the sixth iteration is accomplished, the maximal absolute value of error of coordinates is only as follows: ΔR=7.03E-04m, Δθ=6.7E-0°, ΔZ=.04 E-0m，which is satisfied to the engineeringoriented need. The arithmetic also ensures the continuum and integrality of the structural forming and loading analysis, and is quite fit to the formfinding study of ISFSL. 2349|1065|4更新时间：2023-11-28
- 摘要：The damage failure mechanisms of coalrock under unloading condition during deep mining is different from those under traditional loading condition, starting from the unloading condition position to study the dynamic disaster of coalrock has become a new direction in the disaster study. The rock mechanics electrohydraulic servo test system (MTS815) and acoustic emission system (8CHS PCI2) are used to study the coalrock deformation damage and acoustic emission (AE) characteristics. The results show that the failure of coalrock under unloading condition exhibits strong brittleness and happens in sudden and is mostly of tensileshear failure type. The evolution curve of cumulative ringdown count of acoustic emission can better reflect the coalrock unloading damage evolution process, and the whole unloading failure process can be divided into three stages: the stage of damage weakening, damage stably development stage and the stage of accelerated damage development. During the mining process the confining pressure of the coalrock is unloaded, the coalrock rapidly arrives at the third stage of the whole unloading failure process, and the damage is accumulated rapidly and the fracture failure of coalrok occurred suddenly, then follows the coalrock dynamic disaster.2810|1964|9更新时间：2023-11-28
- 摘要：Based on the uncertainty measurement theory, a uncertainty average clustering measurement model for tunnel surrounding rock classification was established. Due to the uncertain factors in judging the engineering quality of rock masses, seven indexes, i.e., the rock grade, rock weathering degree, rock mass structure, elasticity longitudinalwave velocity of rock mass, influence degree of geological structure, development of joint fissure and ground water regime, were used as the discriminating factors. the indexes functions of unascertained measurement of 20 sets of rock samples were established, and the centre of the classification was indicated by using the average of classification of samples. The weight of indexes was calculated by entropy weight theory, and a prediction for the classification of residual tunnel surrounding rock was carried out using the rules of credible recognition. Each of the 20 sets of tunnel surrounding rockmass samples was tested according to the model, and the correctness rate is 100%. The other 10 sets of tunnel surrounding rock samples were predicted by using this model. The results show that the uncertainty measurement model classification agrees well with the actual measured ones. Therefore, it shows that the uncertaity measurement model is effective, available and can be applied to classification of tunnel surrounding rock in underground engineering. 3533|1511|7更新时间：2023-11-28
- 摘要：The stability of rock mass project is mainly controlled by the rock mass structure, and faults are the large geological discontinuity plane commonly encountered in rock mass engineering. The stability of surrounding rocks is restricted by mechanical property and location to underground cavern of faults, the detailed studies carried out by analysis of numerical calculation and construction monitoring datum of underground powerhouse of Three Gorges Project show: the distribution of stress and deformation of surrounding rock masses containing a fault are badly deteriorated, the distribution of stress and deformation are obviously different under different natural stress field and position of fault; The influence of friction strength of fault on deformation of surrounding rocks is more obvious when a fault is located near the crown, but the cohesion is more when wall nearby, and the influence is more distinct with side pressure coefficient increases.3365|1352|9更新时间：2023-11-28
- 摘要：In the construction of hydraulic tunnel, the engineering quality problem is often caused by concrete cracks and insufficient thickness of roof lining. This problem attracted great attention of the most engineers that whether the structure performance of this kind of lining can meet the design criteria or not, especially under unfavorable conditions. Based on the onsite inspections of the lining defects in Baishanzui tunnels, the model and size of the defects are analyzed with FLAC program. The study shows that the defects have obvious adverse influence on the stability and safety of the tunnel lining, however, if a backfilling grouting is carried out and the cracks are repaired, the integrality of lining is restored, the behavior of lining will be improved and can meet the design criteria as well. 2676|1586|1更新时间：2023-11-28
- 摘要：The microbiology was introduced in foundation treatment. Several Carbonatemineralization microorganisms and polysaccharides viscose microorganisms were screened and the microorganisms No.ATCC 6453，3，polysaccharides viscose microorganisms 5 and 6 were used in silt modification. The engineering properties of silt before and after modification were compared by unconfined compressive strength test and indoor seepage test. The microstructures of silt incorporating different microorganisms were analysed by mean of scanning electron microscope and energy dispersive Xray (EDX) analysis. And the modification mechanism of silt has been revealed. These studies indicate that certain engineering properties of silt can be improved by incorporating microorganisms.2909|1588|16更新时间：2023-11-28
- 摘要：Based on the problem during the practice in geological hazard susceptibility zoning, by constructing the threemark (-1，0，1) matrix and introducing optimum transfer matrix, the faintness about weight choice and the consistency check method of judgment matrix for traditional AHP were improved，and the difficult weight quantization problem for each appraise factor of the hiberarchy model had been solved; accordingly, the Improved AHP model had been built. At the last, this method was applied to a concrete zoning practice about geological hazard susceptibility.The application result shows that the zoning practice in Yongchuan region about geological hazard susceptibility is practical and effective.2510|551|13更新时间：2023-11-28
- 摘要：Safe evacuation is the most fundamental requirement of fire safety measures in buildings. Many computer based evacuation models have been developed to quantify and model human movement in the buildings. Two methods are usually used to represent the building enclosure in these models: fine and coarse networks. This paper presents a fine network model and a coarse network model based on these methods respectively, and develops an integrated network model that integrates both network methods for efficient and detailed assessment of evacuation in large and complex buildings. To demonstrate the advantages of using the integrated network model, the results of its simulation for a highrise office building and a large shopping mall are discussed and compared to the simulation results of the fine network model and the coarse network model. It shows that the integrated model can be used to simulate evacuation in large and complex building and is adequate in representing details of the evacuation process. 3931|529|3更新时间：2023-11-28
- 摘要：The advantages and shortcomings of traditional method and Finite Difference Method (FDM) for the calculation of cantilever slab model with void beneath cement concrete slab corner and analysis on the results were carried out. The traditional method assumes that the cement concrete slab with void below was a cantilever slab with constant sections. The influence of loading eccentricity was not considered while more than two wheel loads were exerted on the concrete pavement, which can be overcome by using Finite Difference Method. With FDM, the stress and displacement distributions of any parts of the cement concrete slab can be easily achieved. The results indicate that when the concrete slab with void beneath the slab corner was assumed to be a cantilever slab, regardless of calculation by traditional method or by FDM, the cement concrete pavement will be destroyed even under the condition of minimum traffic grade. The fatigue stress and road deflection obtained by FDM are bigger than that obtained by the traditional formula, so bigger safety factor should be employed in the road design.2907|330|2更新时间：2023-11-28
- 摘要：The study on the coordination deformation between asphalt mixture and Fiber Bragg Grating strain sensor (FBG) is the precondition and foundation to solve the problem of FBG application in pavement. According to the two kinds of FBG developed recently (they were classified into three categories based on the application features), we designed an accuracy evaluation testing method for FBG and asphalt mixture coordination deformation, and conducted the strain test of asphalt mixture by static loading and dynamic loading. The result indicates that using FBG after strain modification to measure the internal stain of the pavement structure is feasible. Compared with other kinds of sensors, module matching FBG has a better test effect, and this kind of FBG is able to reflect the accumulative deformation of asphalt mixture to some extent.3118|389|13更新时间：2023-11-28
- 摘要：Based on the structural feature of dumbbellshaped section of concretefilled steel tube (CFST), a combined spatial beam element is presented. In this structure, two steel tubes, two core concretes, one web and the concrete in web cavity are firstly considered as general spatial beam elements, then they are assembled into a spatial combined beam element according to the plane hypothesis and transformation matrix formed from master and slave nodes. A FORTRAN program for CFST arch with dumbbellshaped section has been developed, and the numerical example shows that the steel tubes and core concretes bear mainly the axial forces with small moments, thus, a modified formula for lattice column method to calculate axial forces of the upper and lower limbs of CFST with dumbbellshaped section is deduced. Comparison of the results from the modified formula with those from an example indicates that the modified formula gives relatively accurate results. 2931|283|2更新时间：2023-11-28
- 摘要：In the research of settlement renovation nowadays, because of the lack of a quantitative analysis, it was difficult to get a scientific, reasonable, systemic quantitative conclusion. This paper is presented to build a scientific,systemic and quantitative analysis method through which many influence factors invloved in the research of settlement, such as physical environment, social behavior and relatoins among these factors were quantitatively analyzed to get a system with generative simulation in the whole and detailed quantitative analysis for each individual factor, and to make the communication and judgement of the result easy. 3561|394|1更新时间：2023-11-28
- 摘要：Transit oriented development (TOD) presents a sustainable urban development strategy by creating an efficient integration of land use and public transit. A TOD planning model for the land use of urban rail station area was explored by means of a multiple objective mathematical programming model. Three objectives were considered: encouraging transit system volume, promoting livable communities, and balancing land use. The model can easily be solved by transforming it into a linear multiprogramming problem. The Xujiahui rail rapid transit station area in Shanghai is chosen as case study to illustrate the model application and planning results. The result indicates that the model would be efficient in practice.5512|380|4更新时间：2023-11-28
- 摘要：To make the biomass tablets heated fully in a fluidized pyrolysis liquefaction process, it ought to be ensured that sufficient biomass granules stay long enough in the bed so as to meet or exceed the expected pyrolysis temperature. That is, the prerequisite is that the staying time must be more than or equal to the pyrolysis time. However, the staying time is decided by the flow speed and CFB parameters, and the pyrolysis time is controlled by the heat transfer process of biomass particles in a fluidized bed both of which are closely related to the parameters of biomass particles. This paper analyses the heat transfer process of the biomass in the pyrolysis reaction tower, establishes a simplified model of heat transfer with a gassolid flow, studies the rule of pyrolysis time and staying time changing with the biomass size and finds out a theoretical method of selecting the expected parameters of biomass granule to ensure the full pyrolysis of biomass materials.3309|378|0更新时间：2023-11-28
- 摘要：Yangtze River is abundant of water and can provide enough water as cooling and heating source for water source heat pumps (WSHP). A pair of contrast experiments with openloop system and closeloop system of WSHP were finished in order to get the heat pump's COP, the system's COP and the distribution of water temperature in the heat exchanger etc. This paper compared the characteristic and the COP of these two kinds of system. The heat pump's COP of the openloop system and closeloop System are 3.08 and 3.77 respectively, and the system's COP are 2.83 and 2.80 respectively. At last, applications of openloop system and closeloop System of WSHP at Yangtze River were analyzed and the key problem for attention was pointed out in the paper. 3409|765|5更新时间：2023-11-28
- 摘要：Heating with gas can reduce air pollutant emission and therefore becomes a new sort of peak load heatsource. To study the atmospheric environmental impact, we adopted a newly built combined heating system and simulated its pollutant dispersion for centralized and distributed peak heating. The simulations were based on the improved regulatory environmental impact assessment (EIA) guidelines for atmospheric environment. The model developed an algorithm for infillwinddirection simulation and exported pollutant contours for comparisons. Simulation results show that the system's atmospheric environmental impact is related not only to the pollution emission quantity per quantificational heating, but also to the distribution of heat resource in the gas fired boilers. The centralized peak heating has comparatively small environmental impact; for distributed peak heating, the more concentration of gas fired boilers distribution is applied, the more serious environmental impact will be. In addition, the optimum setting proportion of gas fired boilers should be between 0.2 and 0.6 from the perspective of environmental impact.3128|345|0更新时间：2023-11-28
- 摘要：This study reported the feasibility of adsorption of heavy metals from acidic solution using chestnut inner shells (CIS), an environmentallyfriendly natural adsorbent. The adsorption characteristics of CIS for heavy metals were studied by a series of lab scale experiments. The result of adsorption test shows that CIS gives effective removal of heavy metals from acidic solution (pH 2), attaining Cd 98.9%, Pb 99.6%, Zn 98.9%, Cu 98.7% with addition of 30 g/L CIS within 1 h. Thermodynamical test shows that the adsorption capacities of CIS for four kinds of heavy metal are Cd 3.2, Pb 90.8, Zn 27.3, Cu 52.4 mg/g. A kinetic test shows that the adsorption equilibrium is attained within 1 h, and the kinetic behavior of adsorption could be described by Elovich Model. The relationship between the adsorption rate and reaction time is in adverse proportion. At the same time, the adsorption of CIS on Cd, Pb, Cu, Zn is followed by specific order, Pb2+>Cd2+>Cu2+>Zn2+. 3703|1563|1更新时间：2023-11-28
- 摘要：The distribution of turbulence intensity under different rotation speed was analyzed to seek micro indexes reflecting hydraulic conditions of active sludge system by PIV (Particle Image Velocimetry) in a stirring SBR (Sequencing Batch Reactor). Based on the SBR degradation capacity, flocs structure under different rotating speed of stirring paddle, the influences of turbulence intensity on the degradation capacity were studied, and the indexes of turbulence intensity in the main part of stirring zone and other parts were given. The results show that the specified degradation constant of the pollutants in the active sludge reactor increases firstly and then decreases with the increasing of turbulence intensity. The optimum indexes of turbulence intensity in the experiment are 1.4% of main part and 0.34% of other parts. The turbulence intensity indexes in the active sludge system reflect part differences of hydraulic conditions. The turbulence intensity has remarkable influence on the breaking up of active sludge in the main part of stirring zone, while it has good correlation with the collision and gathering of sludge flocs in other parts of the reactor.2698|928|1更新时间：2023-11-28
- 摘要：Life Cycle Assessment(LCA) technology is an effective means in determining sewage treatment processes scientifically. This paper uses a sewage treatment process facility as the main line with the application of LCA technology. The Whole Life Cycle of the municipal wastewater treatment plants is divided into three stages：construction stage, operation stage, discarding and removing stage. This paper analyses the whole life cycle of the municipal wastewater treatment plants by the basic framework of LCA. Not only environmental load but also economic and technical factors are contained in the LCA mode. It is demonstrated by the concrete example of two municipal wastewater treatment plants, with evaluating the advantages and disadvantages of the two treatment processes accordingly. 3635|2152|3更新时间：2023-11-28
- 摘要：The removal of oxytetracycline (OTC) in water by UV, UV/TiO2, UV/Zeolite, and UV/Composite photocatalyst with different ratio was investigated respectively with a 32W lowvoltage mercury lamp. The effects of composite photocatalyst concentration, initial OTC concentration and pH value on degradation were also investigated. It was shown that the UV/Composite photocatalyst with 10% TiO2 and 90% Zeolite was an effective one to remove OTC in water. And in a solution with 50 mg/L OTC in ultrapure water the OTC was removed by 99% within 120 min with the help of 300 mg/L composite photocatalyst. The degradation of OTC by UV/Composite photocatalyst was little influenced by its initial concentration, but influenced by its initial pH. In the environment with pH+2~10, the OTC was removed by more than 95% within 120 min with the help of UV/Composite photocatalyst, when the pH is above 10, the removal rate is rapidly decreased. 3074|1861|3更新时间：2023-11-28
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