bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of Stability and Reinforcement of Faults of Baihetan Arch Dam
Authors: Guan Fu Hai , Liu Yao Ru , Yang Qiang , Yang Ruo Qiong
Published: May 2011

With the deformation reinforcement theory (DRT), numerical simulation of Baihetan arch dam and foundation is carried out. According to the unbalanced forces distribution, fault F18and shear zone LS3318are the key reinforcement regions and unbalanced force of each fault is the corresponding optimal reinforcement force which is to maintain a stable state. To verify the validity of the results of numerical simulation, geomechanical model test of Baihetan arch dam is carried out. By analyzing displacement of corresponding measuring point in the overloading process, and observing failure of transverse section at each elevation, the results show that the unbalanced force distribution of each fault is consistent with the damage law of faults in geomechanical model test.
Two-Way Pre-Stressing Technology Applied to Large-Scale Aqueduct of Tanglai Channel through Beita Lake
Authors: Li Zhuo , Liu Si Hong , Yang Xu Dong , Mai Shan , Feng You Ting
Published: May 2011

In view of particularity of the Tanglai channels aqueduct，which crosses Beita Lake, the conventional construction methods and technologies fail to work, so the new two-way pre-stressing technology is employed. After the sidewalls in large span structures of aqueduct were pre-fabricated and hoisted，the secondary floor was poured in design and construction plan. The results show that the comprehensive function of aqueduct is implemented in complicated conditions，such as short construction period，larger span of structures，navigation under aqueduct，pre-fabrication and hoisting of larger sidewalls. The stress and deformation of aqueduct meet the requirements of design code.
Strain-Rate Sensitivity of Concrete: Influence of Temperature
Authors: Yan Dong Ming , Xu Wei
Published: May 2011

Knowledge about the dynamic properties of concrete is vital to the design and safety evaluation of large-scale concrete structures subjected to seismic excitation. There are many factors affecting the dynamic properties of concrete such as moisture content and temperature. Though a lot of concrete structures have been designed to withstand low temperature, research on the strain-rate sensitivity of concrete under low temperature condition is still very limited so far. In this study, both tensile and compressive experiments were carried out to investigate the influence of temperature on the rate-dependent characteristics of concrete. Tensile experiments of dumbbell-shaped specimens were carried out on a MTS810 testing machine and compressive tests on cubic specimens were performed using a servo-hydraulic testing machine. Specimens at two types of temperature, room temperature 20oC and low temperature -30oC, were characterized. The strain rate varied over a wide range. It was concluded from the test data that the strengths of specimens at both types of temperature tended to increase as strain rate increased. Temperature had slight influence on the rate-sensitive behavior of concrete when concrete specimens were dry; however, test on saturated specimens indicated that the role of temperature on the mechanical behavior of concrete subject to dynamic loading was very significant. This phenomenon may be attributed to the state of free water in concrete.
Analysis of the Tensile Cracking of Rock-Concrete Materials Based on Elasto-Viscoplastic Model
Authors: Huang Yao Ying , Zheng Hong
Published: May 2011

Suppose there is time course during the cracking and deforming process, the tensile cracking of rock-concrete materials was analyzed by means of elasto-viscoplastic model and its calculation steps were illustrated as well in this paper. The expression of function Φ in elasto-viscoplastic theory was studied; what’s more, it was comparatively analyzed the tensile cracking of rock-concrete materials by elasto-viscoplastic model and the maximum tensile stress criterion respectively. There are some differences comparing with the study of plastic yield by elasto-viscoplastic model, when analyzing the tensile cracking of rock-concrete materials on the basis of elasto-viscoplastic model, the function Φ should be the stress or stress formula of the direction where the principal stress firstly reaches the tensile strength; it is proved by the example analysis that it is feasible to study the tensile cracking of rock-concrete materials by elasto-viscoplastic model and there is no iteration stability issues.
The Study of Cemented Sand and Gravel Constitutive Model
Authors: Sun Ming Quan , Yang Shi Feng
Published: May 2011

Basing on triaxial experiments, the paper conducts the research to Cemented Sand and Gravel constitutive model. Using virtual rigid spring method, the Cemented Sand and Gravel constitutive model with considering the softening characteristics of material is established, and parameters needed are determined, the model establishes the foundation of non-linear analysis of Cemented Sand and Gravel structure. Mechanical properties and constitutive model study of Cemented Sand and Gravel is key to Cemented Sand and Gravel faced eath-rockfill dam. Basing the Mechanical properties triaxial experiment of the material, the paper gives further discussion on the constitutive model of Cemented Sand and Gravel. From the results of the triaxial test, when the cemented material content is smaller than 20kg/m3, the stress strain curve agrees quite well with hyperbolic law to which the normal gravel test curve also obeys, the exception is the increase of shearing strength. If the cemented material content is more than 30kg/m3, there is a peak value on the stress strain curve, the curve (before peak value) shows that axial strain increase with deviatoric stress with the increment gradually changing slowly, i.e. the stress strain curve has obvious nonlinear feature. the curve peaks value at the axial strain =2％, the stress strain curve present softening pattern that deviatoric stress decreases with the strain increase if continuous applying axial load. When axial strain lies between 2% and 6%, the shearing strength of samples decreases rapidly, after this interval, the shear strength tends to the stable value in the final. It is core problem the paper try to solve that how to describe Cemented Sand and Gravel constitutive model.
Research on Mechanical Properties and Sectional Form of CGS
Authors: Sun Ming Quan , Yang Shi Feng
Published: May 2011

CSG is a kind of new dam type between earth- rockfill dam and concrete gravity dam. It proved to be feasible under massive experiment about the mechanical properties of CGS. Our research group believes that the sectional form changes correspondingly different content of gelled material and controlling factors of dam stability. Then the research of thought and design theory are put forward, and existing problems of current works was studied as well.
Appliance of 3-D Composite Layered Element in RCC Dam
Authors: Gao Rui
Published: May 2011

A numerical calculation method and a new type element of EFM for the simulation of the RCC dams is presented. It takes into account the more relevant features of RCC, such as the transversely isotropic, the layered character, the strength unequal to tension and compress and the discontinuities. A 3D model of RCC Dam, built in South-West of China, is used to perform the corresponding analyses. The result shows the location of third height to dam heel in upstream dam will be crack between layers. So it is very dangerous for arch dam. In the the locations of third height to dam toe and dam crest of the downstream of the dam will occur the stresses concentration, so some of engineer measures must be adopted to avoid the damage.
Uniaxial Compressive Strengths of Artificial Freshwater Ice
Authors: Zhang Li Min , Li Zhi Jun , Jia Qing , Li Guang Wei , Huang Wen Feng
Published: May 2011

The uniaxial compression test was performed on artificial freshwater ice with a precise control-temperature unit compression tester of ice under -5, -10, -15, -20 and-30°C temperatures and strain rates ranging from 10-8 to 10-2 s-1. The loading direction was parallel to ice surface. The results showed that the compressive strength was very sensitive to the strain-rate. The uniaxial compressive strengths reached the maximum value at the ductile-brittle transition region, and the region was gradually close to the lower strain-rate with the decreasing temperature of test. Both the strain-rate and uniaxial compressive strength dependences could be expressed in terms of power function in the relevant ductile range of strain-rate. The tests also revealed that failure stress of ice increases with decreasing of temperature at the same strain rate.
Rheological Fracture Analysis of Arch Dam Hell
Authors: Yang Ling Qiang , Chen Ying Ming
Published: May 2011

Based on the normal H-K rheology model, a new rheological model containing fracture elements for concrete or rock cracked body is introduced. The method to ascertain rheology state is put forward. The new rheological model can change to Maxwell or Kelvin model to express the instantaneous failure, delayed failure state and the accelerating segment. The researching failure element method was used to study the crack propagation. Then the cracking elements were studied using rheology mechanics to solve the cracking time. At last a case study was given to validate the method is feasible.
Seismic Response of Submerged Floating Tunnel Based on Numerical Analysis
Authors: Su Zhi Bin , Sun Sheng Nan
Published: May 2011

To study the seismic response of submerged floating tunnel, a numerical model of submerged floating tunnel is set up based on the potential fluid theory. According to the parameters of designed submerged floating tunnels at home and abroad, main factors that affect the dynamic response of submerged floating tunnel were analyzed by numerical method. The results show that, the investigated parameters, such as tether spacing, external diameter of tube, immersion depth of tube, water depth and tube concrete thickness, have strong influence on the global behavior of the submerged floating tunnel. Definitely, by the caring choice of such features, it is possible to optimize the submerged floating tunnel structural behavior.
Anti-Seismic Capacity Analysis and Structural Appraisal & Reinforcement of a Multi-Story Masonry Building with Load-Bearing of Longitudinal Wall
Authors: Ma De Yun , Zuo Yong Zhi , Teng Hai Wen , Huo Da
Published: May 2011

Based on the analysis for damages of masonry structure from Wenchuan earthquake, the seismic behavior of multi-story masonry school building is analyzed, and the seismic behavior with load-bearing structural system of longitudinal wall is mainly discussed. Based on the analysis and study, several problems which need more attention to the seismic appraisal and reinforcing design are pointed out, and finally the differences and correlation of seismic appraisal, as well as seismic design are discussed.
Study on the Mechanism of Magnesium Sulfate to Cement and C-S-H Gel
Authors: Li Xiu Juan
Published: May 2011

The microstructure of cement test block and the C-S-H gel attacked by magnesium sulfate is observed by means of scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS)and X-ray diffraction(XRD).It is found that the presence of Mg2+ makes C-S-H gel decalcify, dissolve and decompose, which thereby increasing the erosion of SO42- on the concrete. The decomposition of C-S-H and the generation of M-S-H result in the loss of concrete strength and the ultimate destruction of concrete.
Nonlinear Dynamics of Supported Cylinder Subjected to Axial Flow
Authors: Jin Ji Duo , Qin Zhao Hong
Published: May 2011

In this paper, the stability and nonlinear dynamics are studied for a slender flexible cylinder subjected to axial flow. A nonlinear model is presented, based on the corresponding linear equation of motion, for dynamics of the cylinder supported at both ends. The nonlinear terms considered here are only the additional axial force induced by the lateral motions of the cylinder. Using six-mode discretized equation, numerical simulations are carried out for the dynamical behavior of the cylinder to explain, with this relatively simple nonlinear model, the flutter instability found in experiment. The results of numerical analysis show that at certain value of flow velocity the system loses stability by divergence, and the new equilibrium (the buckled configuration) becomes unstable at higher flow leading to post-divergence flutter. As the flow velocity increases further, the quasiperiodic motion around the buckled position occurs, and this evolves into chaotic motions at higher flow.
Numerical Simulation of the Dynamic Behavior of Deep-Water Semi-Submersible Platform under Wind and Waves
Authors: Zhai Gang Jun , Tang Dong Yang , Xiong Hong Feng
Published: May 2011

Taking a deep-water semi-submersible drilling platform and its mooring system which will be used in South China Sea area as an example, the motion responses of this platform in the frequency and time domains are analysed. In the frequency domain, the three-dimensional potential flow theory is emploied to calculate, the response function of six degrees of freedom and some hydrodynamic parameters, such as additional mass and additional damping. In the time domain, the non-linear time-domain coupling analytical method is used to calculate the motion responses of this platform under the action of wind and waves. Then according to the time series of motion response, the influence of the Jonswap spectrum’s parameters, including wave height and peak factors on the platform’s heave response is analysed.This numerical simulation results provides an reference for the target platform’s actual construction.
Experimental Study of Sea Ice Forces on a Structure and its Stability
Authors: Dong Ji Wu , Li Zhi Jun , Zhang Li Min , Li Guang Wei , Han Hong Wei
Published: May 2011

A structure was designed to reduce the large forces exerted by level ice on offshore structures in shallow icy waters, by breaking the large ice floes into small pieces from flexing-induced failure. A series of model tests was conducted to simulate ice loads on the structure. A concrete model of it was adopted to verify the stability of the structure under the action of ice floes, which had five different thicknesses. The results show that ice forces on the structure are low and that the stability of the structure under different sea bed is good.
Analysis of the Energy Efficiency of Frequency-Changing Water Supply by Secondary Pressurizing in Residence Community
Authors: Li Ya Feng , Zhang Xiao Ning , Chen Wen Tong
Published: May 2011

In order to run the secondary pressurizing pump station in the residence community more economically, the operating principles, control methods and suit conditions of four kinds of water supply systems were introduced and they are: common circular soft started constant pressure frequency-changing system, circular soft started constant pressure frequency-changing system with little capacity pumps, high efficiency frequency-changing system within full flow area and variable flow and pressure system. The energy efficiencies of these kinds of water supply systems were analyzed with their engineering applications. The issues to be concerned in these water supply systems were also discussed.
Influence of Catalytic Conditions on Hydrogen Peroxide Decomposition by Modified Activated Carbon
Authors: Huang Xiao Hua , Liu Zhen Zhong
Published: May 2011

Iron and manganese oxide /activated carbon composite (GACF1M3) was prepared and the experiment conditions including pH ,GACF1M3 dosage and organic effect were evaluated in the H2O2decomposition. The results showed that the decomposition of H2O2increased with time ,GACF1M3 can decompose H2O2about 75% in 120min . The amount of H2O2reflected the maximum usage rate of the GACF1M3 when the dose was 100mg. The highest H2O2decomposition of GACF1M3 was achieved at pH 8.5, the maximum OH· production was pH 5.0.The presence of HA can increase H2O2decomposition while TCP has the opposite effect.
Operation and Maintenance of Wastewater Treatment Plants: Case Studies in China
Authors: Yin Meng Meng , Zhang Ke Feng , Wang Yong Lei
Published: May 2011

This paper considers on-going problems relevant to operation and maintenance in wastewater treatment plants in China. Positive and negative practices in developed countries such as the UK and U.S. have been indicated for the purposes of comparison. This research looks at the aspects of institutional structure, human resource management, public participation, financial resources, and technical management which have been regarded as the key points to analyse for effective wastewater management. Relevant information has been collected and analysed to develop appropriate solutions that would assist decision-makers and operators to solve some of the problems of wastewater management and to operate and maintain wastewater treatment plants in China properly.
Regulating Strategies of Strengthening Nitrogen Removal for Low-Carbon Wastewater in Reversed A2/O Process
Authors: Chen Jie Yun , Zhang Zhi , Xie Li Hua , Kong Ling , Yin Xiao Jing
Published: May 2011

According to the ineffective denitrification and the initial controlling technique flaws for low-carbon source in reversed A2/O process, and full scale experimental studies were conducted to strengthen denitrification at normal and low temperature days in 2008~2010, to ensure the best conditions of biological denitrification and promote the stable and efficient operation of the system. The results showed that in normal temperature seasons of 2008, after shortening the HRT of the primary sedimentation tank to 1/3 of design value, improving the MLSS to 4500mg/L, setting the first section of the aerobic zone as the denitrification transition section and improving the reflux ratio, available carbon source was increased by 15%, the effluent NH3-N was 2.5mg / L and the removal rate was 90%, the effluent TN was 17 mg/L and the removal rate was increased to 54% and unit power consumption was reduced by 15% to 0.22Kw•h/m3.At low temperature seasons of 2008~2009,by improving the MLSS to 6000mg/L, extending the sludge age to enrich a large number of nitrification and denitrification bacteria, controlling DO at about 1.2mg / L in the aerobic zone and so on, the effluent NH3-N was 3 mg / L and the removal rate was 88%, the effluent TN was 15.5 mg/L and the removal rate was 62%. In low temperature of 2009 ~2010, besides the same measures as before, adding a blender in the first section of the aerobic zone to provide a better anoxic environment for denitrification and to improve nitrogen removal, the effluent NH3-N was 3 mg / L and the removal rate was 87%, the effluent TN was 13.5 mg/L and the removal rate was 66%.
Study on the Short-Cut Nitrification which in a Sequencing Batch Reactor (SBR) under the Effect of Sludge Age
Authors: Yang Hui , Cui Hui Hui , Zhang Yu , Xu Yue
Published: May 2011

Sludge age (SRT) is one of the primary influencing factors in the system of short-cut nitrification, in order to select a suitable SRT, in the stable operation of SBR, with the simulated wastewater as treatment object, the response effect and the sludge floc characteristics of short-cut nitrification are investigated by changing the SRT. Experiment has proved that the longer SRT the more complete nitrification. When the SRT for the 10d time, the NO2--N accumulation rate was maximum. When the SRT is short, the biological floc phase composed mainly by bacilli, and the surface of the sludge floc is rough and structure is loose. When the SRT is longer, the reactor's biological floc phase mainly composed by the coccus and has got relatively smooth surface with a compact structure. Rod-shaped bacteria are the good characteristics of the phenomenon of the short-cut nitrification.
Phosphorus Removal in Biological Aerated Filters by Chemically Enhanced
Authors: Ma Ying Ying , Li Xin , Dong Wen Yi
Published: May 2011

Phosphorus removal by biological aerated filter(BAF) is ineffective, its effluent TP is much more than 0.5mg/L, so chemically enhanced phosphorus removal is neccessary. To solve this problem, domestic wastewater through BAF by adding metal salts in the aerobic tank was studied. The ferric chloride and aluminum chloride were chosen as the metal salts. The results showed that: the removal rate of TP rose with the Me/P (Me=Fe, Al)mass ratio increased, the influence on other performance of BAF by chemically enhanced synchronously was not severe, with TP in the effluent below the standard of 0.5mg/L; to ensure the concentration of effluent TP was less than 0.5mg/L, the optimum mass ratios of dosing were Fe/P=3, Al/P=2.5; proper aeration intensity could maintain the proper micro-flocculation state in BAF, which was helpful to TP removal.
Study on the Characteristics of Biodegradable Dissolved Organic Carbon and Bacteria Regrowth in Drinking Water Distribution-System of a Chinese City
Authors: Ma Jian Wei , Liu Jun Liang , Li Xin
Published: May 2011

Many researchers pay their attentions to the biostability of drinking water more and more. Biodegradable dissolved organic carbon can provide a good indicator for biostability of drinking water in distribution-system. The main objective of this study was to research the regulations of concentration changes of biodegradable dissolved organic carbon and the populations of the total bacteria in water distribution-system of a city in china. The field experiments showed that the values of biodegradable dissolved organic carbon decreased along the main pipes in the water distribution-system, and the rate of the decrease was lower in the front part of the two main pipes than in the back part. At the same time, the populations of the total bacteria increased in the front part of the NO.1 main pipe and decreased in the back part. Our research provided the theoretical foundation for limiting the bacteria regrowth and to ensure the biostability of drinking water.
Catalytic Decomposition Kinetics and Mechanism of Hydrogen Peroxide by Modified Activated Carbon
Authors: Liu Zhen Zhong , Deng Hui Ping , Chen Zhan Li
Published: May 2011

Modified activated carbon composites were prepared and their catalytic properties were evaluated in the H2O2decomposition. Activated carbon alone showed very low activities compared to iron and manganese oxides / activated carbon composites, suggesting that the presence of Fe and Mn in the oxide plays an important role for the activation of H2O2. The presence of Mn in the composite structure produced a remarkable increase in the reactivity. The obtained results showed that the peroxide decomposition catalyzed by GACFM met pseudo-first-order kinetic and the maximum OH· production was on GACF1M3.The decomposition mechanism of H2O2was analyzed in detail.
Investigation on Double-Tube Copper-Aluminum Column-Wing Type Radiators
Authors: Liu Jie , Zhang Shuang Xi , He Yu Feng
Published: May 2011

The calculation formulas are provided for calculating the heat release and metal thermal intensity of double-tube copper-aluminum Column-wing type radiator, and the reliability of the theoretical calculation is verified. The metal thermal intensity is taken as an optimization index, with theoretical calculations for different sorts of tube diameters and overall dimensions, obtains the optimalizing dimension of the radiator.
Study on Fire Smoke Control of Underground Annular Channel
Authors: Jiang Xue Peng , Chen Rui Yu , Xu Zhi Sheng
Published: May 2011

Aiming at the characteristics of many crossroads and large slope of ground exits in Suzhou Underground Annular Channel, fire resistant shutters were advised to set as flexible compartment. The whole channel was divided into 6 smoke control sections by fire resistant shutters and exits and ventilation shafts. The schemes of smoke control and people evacuation were presented. Smoke flow in 6 fire scenes was simulated by FDS 4.0. The results show that fire smoke could be discharged to ground along planned route to ensure the safe evacuation of people and cars, and show that the smoke control schemes are reasonable and effective.
Experimental Study of a Solar Assisted Air Source Heat Pump in Heating Condition
Authors: Liu Yin , Zhou Guang Hui , Ma Jing
Published: May 2011

In order to improve the performance of air source heat pump in low temperature conditions, designed a solar assisted air source heat pump with the gas-liquid bio-sources heat exchanger. The heat pump can work with solar heat water and air as a heat source at same time. The heating performance of the heat pump in low temperature conditions was tested. The results show that, in comparison to the single air source heat pump, the heating performance of the solar assisted air source heat pump is improved remarkably. When the solar water flow is at 0.6m3/h and the outdoor environment temperature is -7°C, the heating capacity raised about 38% and the COP raised about 30%. When the outdoor environment temperature is -15°C, the heating capacity and the COP all raised more than 50%.
Decoupling Control of Gas Mixing Based on Fuzzy-Single Neuron Adaptive PID
Authors: Xu Shao Chuan , Jing Yuan Wei
Published: May 2011

The gas mixing pressuring and calorific value control of gas mixing process have the characteristics of strong coupling, nonlinear, uncertainty and large time-varying. If the calorific value of mixing gas is unstable in gas pressurization station, the quality and quantity of iron and steel production will be affected. In this paper, an compound decoupling control method of fuzzy-single neuron adaptive PID is proposed according to the mixing gas pressure and calorific value decoupling control, the fuzzy decoupling controller is used to realize the initial adjustment of mixing gas and pressure, which has the characteristics of rapidity and anti-interference performance. The fine adjustment work of control process is completed by the secondary adjustment of adaptive PID controller of single neuron, the design of controller has the ability of parameter self-learning, and the simulation results show that this design scheme has a better dynamic performance than traditional PID scheme to verify the feasibility of this method.
Heat Transfer Performance of Integration of Enclosed Evacuated Tube Solar Collectors and Building Envelopes
Authors: Yu Guo Qing , Gong Xiao Hui , Xie Tian Tian
Published: May 2011

A new type of enclosed evacuated tube solar collector integrated with building envelopes is introduced. The distinguished feature of this new device is that gaps between the evacuated tubes are filled with sheet glass and the evacuated tubes, sheet glass and edges form an enclosed cover on the building envelope. The heat loss behind this kind of solar collector is studied theoretically and experimentally and compared with conventional open evacuated solar collector. The results of research indicate that: 1) The air chamber temperature of the enclosed solar collector is rising with the increasing outside temperature and it is much higher than the outside temperature, owing to the enclosed chamber and the solar heat gain in the chamber. For the open solar collector, the air temperature behind the evacuated tubes is nearly the same as the outside temperature. 2) In the night, the heat loss of integration with the closed air chamber door is less than the open one, but the difference is not large. In the daytime, the heat loss through the building envelopes behind the enclosed solar collectors is significantly reduced with the closed air chamber doors.
Test Comparison Research Mechanics Performance between Sisal Fiber Concrete and Rubber Powder Concrete
Authors: Bao Hui Ming
Published: May 2011

By means of the tests on the mechanics performance of the reinforcing concrete mixed with sisal fibers or rubber powder of certain content are investigated. The compressive strength, tensile strength and flexural strength, etc. are compared. The test indicates that when the test condition is same, the compressive strength, tensile strength and flexural strength of the sisal fibers concrete are better than those of the rubber powder’s. The sisal fiber concrete is environment friendly than the rubber powder concrete. And it has widely value of spread and utilization.
Study on Air Conditioning System Design Method of Recreational Guild Hall Based on Architecture Environment Requirement
Authors: Tian Yu Lan , Zhang Wen Yan
Published: May 2011

Recreational guild hall usually has the characteristic of the special architectural form, complex architectural adornment and high requirement of indoor temperature/humidity, airflow distribution, noise and lighting. Air conditioning system design was optimized based on architecture environment requirement of recreational guild hall. The method was applied on the air conditioning system design of Nanjing Longjing recreational guild hall and the effect is satisfactory.
A Proposal for Winter Outdoor Design Temperature of Intermittent Heating
Authors: Wang Ying Ying , Liu Yan Feng
Published: May 2011

Based on the statistical method of the heating outdoor design temperature in HVAC design code, we use two calculation methods to analyze the outdoor design temperature and the heating load of some typical cities for intermittent heating . The results show that: the heating outdoor design temperature is higher 3.8 °C and 4.6 °C than that of the current standard value for long-term and short-term intermittent heating respectively, accordingly, the heating load of the long-term and short-term intermittent heating can be reduced by 9% and 15% according to the new outdoor design temperature calculated by this paper.
Three-Dimensional Numerical Simulation of Downburst Wind Occurrded in Wuhan
Authors: Li Yan , Qu Wei Lian , Wang Bin , Wang Yi Fei , Ji Bai Feng
Published: May 2011

Downburst is a strong downdraft generated below a cumulonimbus cloud, which hits the ground rapidly and causes significant low-level wind shear. It is a strong destructive regional weather phenomenon, which is the main reason for the transmission towers. In recent years, some scholars have researched the finer wind field characteristics and wind load of downburst by using the method of CFD. But the initial conditions are all assumed due to the small synoptic scale, the short lifecycle and the big measurement difficulty of downburst. So downburst wind load can not be taken into account in structural design. Based on the 3-D convective storm numerical model, by inputting temperature, humidity and wind fields detected in Wuhan radiosonde station at 8pm on July,27th,2007, simulation has been accomplished to understand the characteristics of the wind field in the place where the downburst incurred actually. The result provides model data and parameters for CFD simulation, which has directive significance to concern the high intensity downburst wind load in structure design.
Vibration Modes Coupling Effect in the Wind-Induced Response of a Ribbon-Like Long Span Roof
Authors: Li Shao Long , Fan Xu Hong , Chen Jia Guang
Published: May 2011

The test conditions and main results of wind tunnel test for an exhibition hall and a stadium ribbon-like long span roof of a Sports Convention Center are introduced. We got the average and fluctuating wind pressures of the roof. Then we use typical points measuring method to analyze them. According to the energy contribution method, dominant modes are identified, and the modes response energy is calculated. The coupling coefficient between background displacement response and resonant displacement response is presented in this paper. The stadium calculation mode are Analyzed. The results show that the coupling coefficient numerical range for the ribbon-like long span roof is larger than single-layer spherical shell. When we use energy contribution method to select vibration modes in calculating ribbon-like structure response, Error range is large if the coupling effect is ignored, and some compensatory modes need to be found.
Research Progress and Prospect to Civil Engineering Structure Passive Control
Authors: Wu Li Xiang , Qu Shu Ying , Zhang Jia , Hou Xing Min
Published: May 2011

In this paper, the structural passive control which has the broad application prospect in seismic shock resistant and the wind-resistant design of civil engineering is introduced. the principle and wide application of structure passive control technology including basal isolation, energy dissipation damping and shock absorption damping in civil engineering are expounded, and the development for passive control technology development is prospected.
The Time-Frequency Analysis for Energy Dissipation Shed-Tunnel’s Rockfall Impact Signal Based on Wavelet Theory
Authors: Wang Lin Feng , Tang Hong Mei , Chen Hong Kai
Published: May 2011

Shed-tunnel is one of common prevention measures along the highway. Through the wavelet theory we denoised the rockfall impact signal when the rock impact the ordinary shed-tunnel and the energy dissipation shed-tunnel. And then we evaluated the wavelet theory’s denoise effect by the signal-to-noise ratio. The calculation result indicated that the denoise effect is very good. At last, through the autocorrelation analysis and time-frequency analysis for the rockfall impact signal, it was found that the ordinary shed-tunnel’s impact signals didn’t have obvious frequency and the frequency contained many component,but the energy dissipation shed-tunnel’s impact signals had obvious frequency. So the energy dissipation shed-tunnel’s impact signals had a relatively fixed cycle and frequency. The received frequency of rockfall impact by the time-frequency analysis could provide the basis for the design of energy dissipation shed-tunnel’s natural frequency.
Influence of Fiber Geometry on the Mechanical Properties of Ultra-High Performance Fiber Reinforced Concrete (UHPFRC)
Authors: Yang Song Lin , Diao Bo , Ye Ying Hua
Published: May 2011

Ultra-High Performance Fiber Reinforced Concrete (UHPFRC) has been a technological breakthrough offering compressive strength over 100MPa and tensile strength over 10MPa with true ductile behavior. Three types of frequently used fibers including flattened end, hooked end and crimped fibers, were used in producing UHPFRC with fiber volume ratios of 1%, 2%, 2.5% and 3% to investigate different reinforcing effect of fiber geometry on UHPFRC. The results showed that specimens with flatted fibers showed the highest flexural tensile strength, and specimens with crimped fibers showed the lowest flexural tensile strength. The optimum volume ratio for the flattened end fibers or hooked end fiber was 2%. The hooked end fibers were more preferable for producing ductile UHPFRC.
Research on Dynamic Process of Large-Scale High-Speed Landslide Disasters
Authors: Fan Yun Yun , Liu Xiao Li , Wang En Zhi , Wang Si Jing
Published: May 2011

The large-scale high-speed landslide has a strong destructive power which seriously threatens human lives and belongings. In order to study the dynamic process of large-scale high-speed landslide disasters and find the causes, the back analysis is made to study the Frank slide, a typical large-scale high-speed landslide disaster which happened in Canada, by combining dynamic model equation and method of finite volume discretization. At the same time, the simulation realizes the reappearance of the dynamic process of large-scale high-speed landslide disasters. It is can be seen from the calculation results which are identical to the actual situation that the established theoretical model and the numerical solution are effective. Besides, the low bottom friction parameter obtained from the back analysis shows that the decrease of the friction resistance is one of the most important causes of large-scale high-speed landslide. The further analysis reveals that several factors such as high-speed motion, fluid pressure on the sliding surface and high normal stress can reduce the friction resistance on the sliding surface.
Analysis of the Stability Conditions of Qing River Gushubao Landslide Mass
Authors: Shuo Zhang , Wei Tan , Feng Li
Published: May 2011

The stability conditions after the instability of sliding is a concern issue; it is the significant foundation to conduct objective assessment for selecting engineering management measures. According to the geological background and geological exploration data, some representative sections as well as their stability conditions were studied and analyzed based on limit equilibrium method for rigid block and three-dimensional nonlinear FEM in this paper. The impacts on the slop stability by different depths of the transient saturated zone caused by groundwater as well as rainfall infiltration were taken into consideration during the calculation analysis. It is indicated by the results that the impacts on the landslide mass displacement by rainfall have distinguish spatial properties; the impacts on vertical displacement is bigger than that of the horizontal direction; the obvious impacting zone is located in the little backer anterior border area of the landslide mass. The calculation results can provide important references for the control and reinforcement of the landslide mass as well as the prevention of landslide hazard during the later engineering construction activities.
The Influence of Seismic Input in the Oblique Direction on the Strong-Column Weak-Beam Mechanism for RC Frame
Authors: Ma Hua , Liu Chun Yang , Li Zhen Bao , Han Jian Qiang , Chen Shi Cai
Published: May 2011

In current seismic design code of each country in the world, the mainstream of earthquake input for calculating the building is to use X and Y directions conveniently. The X and Y directions are the main axis of the building, and the strong-column weak-beam damage mechanism has been considered only followed to these main axis. However the building response in the oblique direction is higher than in the main axis, and the frequency in the oblique direction of the building is higher than the X or Y direction as well. Moreover the column usually connects with two beams in the orthogonal directions and the strength ratio of the column to beams in the oblique direction is less than in X or Y direction. Therefore it could be the major reason to cause the column-plastic-hinge damage mechanism during the earthquake. In this paper, it is discussed how the seismic input in the oblique direction influence on the strong-column weak-beam damage mechanism for RC frame through the perspectives of the dimensional mechanical analysis, cyclic loading experiment and the finite element analysis for the dimensional column-beam joint, and then proposed that considering the seismic input in the oblique direction is necessary in the future structural design in order to reach the actual strong-column weak-beam mechanism.
The Study of Wind Load Characteristics of Round Earth Building Roof Based on Wind Tunnel Test and Numerical Simulation
Authors: Peng Xing Qian , Shao Kun , Gao Zhi Fei
Published: May 2011

Since the "Fujian Earth Building" was on the list of the world heritage list, the protecting work of Earth Building gets more and more important. This paper adopts the method combining wind tunnel test and numerical simulation, using CFD software to establish the representative building model of round monolayer Earth Building and get the wind load characteristics in different wind direction. And the wind tunnel tests confirmed the reliability of simulated results. The results provide reference to the protection and wind-resistant design for Earth Building and modern building of Earth Building mode.
Analysis and Computation of the Temperature Field of Concrete Filled Steel Tubular Columns
Authors: Han Jin Sheng , Cong Shu Ping
Published: May 2011

The simplified calculation method of the temperature field of concrete filled steel tubular columns under fire conditions was studied for convenience. Firstly, a numerical program of finite difference method was developed to calculate the temperature field of concrete filled steel tubular columns subjected to fire, and the calculation results of the program have good agreement with the experimental results. Secondly, the effects of the steel tube thickness, the steel tube diameter and the type of concrete aggregate were analyzed on the base of plentiful experimental and numerical results. Finally, the effects of some major factors on the temperature field were simplified, and the simplified calculation method was presented to calculate the temperature field of concrete filled steel tubular columns based on data fitting. The precision of the simplified calculation method can satisfy the accuracy requirement of engineering practices.
Nonlinear Stability Analysis on Vessels Subjected to External Pressure
Authors: Teng Zhen Chao , Ji Jing
Published: May 2011

To determine stability performance and the critical load of the short cylinder vessel which is made of steel, this paper carried out the finite element linear buckling analysis for 5 meters long steel pressure vessel and obtained buckling critical load. Then performed the nonlinear instability analysis by the arc-length method and obtained the load-displacement curves of the overall stability of the pressure vessel structure. The critical load can be got by twice the elastic slope method and double-tangent intersection method, and the loads are slightly higher than the result of the theoretical calculation, so the result of the theoretical calculation is safe and reliable. Finally, several measures keeping stability of short cylinder pressure vessel are proposed.
Research on Behavior of Circular Steel Tubes with Different Coating Subjected to Fire Load
Authors: Zhou Ming , Wang Xin Tang , Yin Jie , Xie Zhi Guo
Published: May 2011

The fire experiment was conducted for three of circular steel tubes protected with two different gypsum fireproof panel and the steel tube without any protective material. The fire response temperature of surface of steel tubes was measured and the axial compressive bearing capacity of the specimens after fire were tested and analyzed. The test results show that gypsum fireproof panel has better fire protection characteristics. It is noted that the variation of temperatures of inner surface of gypsum fireproof panel under fire is consistent with the temperature of outer surface of the steel tube. The maximum difference of temperature between the outer surface of the tube and the furnace space is 150°C as the fire keeps stable for the steel tube without any protection. It is concluded that two of the specimens protected with gypsum fireproof panel have larger post-fire capacity, which means that the gypsum fireproof panel has better effect on fireproof of the steel tube under fire.
Simplified Method for Horizontal Displacement Calculation of Frames at Elevated Temperature
Authors: Jing Ya Tao , Wu Bo
Published: May 2011

The paper extracts two types of investigated models from frames in fire according to their horizontal deformation characteristics, and provides a simplified method to calculate horizontal deformation of frames, which can be applied to single- and multi-layers frames. Compared with the results by finite element analysis, it shows that the simplified method is a feasible method for the horizontal displacement estimation of frames in fire, and the treatment of the column restraint rigidity for multi-layers frame is appropriate.
Heavy Metal Pollution of River Sludge in Taiyuan
Authors: Tan Hui Jie , Zhang Chi , Wang Zeng Zhang , Li Ping
Published: May 2011

Samples of the sludge were collected from urban channels in Taiyuan city, and its pollution characteristics of heavy metals were researched. As the emphasis, the distribution regularity of five chemical speciation about Cd, Cr, Zn, Cu, Ni, Pb were analyzed. The results showed that the concentration of Ni, Zn, Cr over standard in various degrees. The residual metal fractions had a higher proportion for all heavy metals. Cd, Zn and Ni were predominantly associated with the carbonates bonded metal fraction and the organics-sulfide bonded metal fraction. Cu, Pb and Cr were predominantly bound to the organics/sulfide and Fe/Mn oxides, but their proportion are different. The bio-transportation index of Zn and Ni are larger than the others. This is the emphasis of heavy metal pollutions control for the local channels.
Study on Synergetic Catalytic Ozonation of Nitrobenzene in Nebulizing Systems
Authors: Duan Hai Xia , Qu Jia Hui
Published: May 2011

The removal effect of nitrobenzene (NB) in water by VUV/O3/GAC synergetic catalyzing method in a nebulizing system was studied. In addition, the effects of the droplet size, the nebulization height, O3 flux, free radical scavengers and active carbon usage frequencies on the degradation of NB were investigated. In this study, a spray nozzle that could produce 10-micrometer droplets were adopted, a UV lamp that emitted 185nm VUV light was used as the light source and a layer of 0.5cm granular active carbon was laid at the bottom of the experimental apparatus. The results showed that, in the apparatus, when the NB concentration in deionized water was 200mg/L, the nebulization height was 1.3m, O3 flux was 150mg/L, the removal rate of NB reached 95.3%. Supercarbonate acted as a catalyst in the system.
Choices of Environmental Policy and Principle Functions Orientated on the Fragile Ecological Areas of Northwest Sichuan Province
Authors: Pei Wei Zheng , Li Jia , Wang Huan , Li Yong
Published: May 2011

Based on the strategy of development priority zones and the requirements of regional policies in China, this paper discusses the main function orientation of ecologically-vulnerable areas of northwestern Sichuan in its social and economic development. A series of development strategies in terms of regional industry development, population distribution, ecological restoration and protection are put forward. Several environmental policies are discussed, such as building up the opening ecological protection mechanism, further improving ecological compensation policy and the establishment of green GDP system. This work has positive theoretical and realistic significance for us to seize the opportunities of the new round of West Development, promote the coordinated development of Sichuan and ensure the ecological safety of the Yangtze River and the Yellow River.
Evaluation of the Low-Emission Construction Model of Steel Structure Civil Building
Authors: Chen Wei , Wan Jing , Cai Yu Chun
Published: May 2011

The increasing world population and the shortage of adequate housing create an enormous demand for future housing with an expectable demand for sustainable solutions. The low-emission construction model of steel building system could be introduced and promoted in the civil building. There are four main ways including the standardized design, industrialized production, assembly of construction and social services to develop this model which can meet the demands of the function goal, the low-emission goal and the cost-benefit ratio evaluation criteria. Which way should be applied as the uppermost one is the key problem to realize the environment protection strategy scientifically in housing industry. The evaluation model was proposed and the AHP method was applied in calculation to draw the conclusion that the standardized is most important countermeasure.
Study on Hysteretic Energy Dissipation of SMA Wires, Bars and Plates
Authors: Zhang Ji Gang , Liu Yan Mei , Zhang Jing Jing , Gao Ke Yong
Published: May 2011

Through tensile tests of shape memory alloy(SMA)wires,bars and plates, this paper analyzes hysteretic energy-dissipating capacities of thesesmartSMA materials in cyclic loading conditions. According to the test results, this article demonstrates the influence on energy dissipating capacity of SMA wires,bars and plates by different strain amplitudes, loading frequencies, cyclic numbers and pre-strains, then obtains change rules of hysteretic energy-dissipation.The test results show that the SMA wires is better than the other two SMA bars and plates, the SMA wires, bars and plates had better to be trainingbefore civil engineering application.