bluuebunny/crossref_metadata_2025 huggingface dataset:
Loading Correlation for Reliability Analysis of Reinforced Concrete Columns
Authors: Tang Chang Hui , Yang You Cheng
Published: May 2011

A major difficulty in reliability analysis of reinforced concrete (RC) columns subjected to both axial compression and bending moments is the interaction between strength of bending and axial compression. In particular, the limit state function cannot be explicitly expressed due to this interaction. This paper analyzes the correlation between load effects. Given the calibration point, a mathematical expression for the load correlation, rMN, in terms of eccentricity of dead load and live load, eG and eQ, is established, which physically clarifies the relationship of rMN with load path. Given the ratio of eccentricity k = eG/eQ and the ratio of load effects r, the reliability analysis for RC columns with considering the correlation between load effects can be analyzed by using the correlation relationship proposed in this study and FORM method. This study provides an effective and practical approach to the reliability analysis.
Lateral-Torsional Coupled Seismic Response of Asymmetric Multi-Tower Base Isolated Structures with Large Floors
Authors: Dang Yu , Huo Kai Cheng , Qin Fang Fang
Published: May 2011

The special type isolated building defined as asymmetric multi-tower base isolated structure with large floor is discussed in this paper. The rigid layers in series models are obtained and the elastic time history method is used to analyze the performance and seismic response of the structure. With the objective of studying the influence of the mass eccentricity in the towers and the asymmetric towers, coefficients of shear force, the ratios of period and the ratios of drift are discussed. The following conclusions have been attained: Torsional drift can be significant depending on the isolated layer in the asymmetric multi-tower with large floor. Comparing with the fixed base structures, this special type isolated building still can be reduced torsional response. The effect of isolation is reduced with the mass eccentricity in the towers and the asymmetric towers increases. It is concluded from the study that the multi-tower base isolated building with large floor should be symmetric and central in order to increase performance of isolation.
Fractal Characteristic Analysis of Seismic Responses of SDOF Systems Subjected to Near-Fault Ground Motions
Authors: Yang Di Xiong , Zhang Chang Geng
Published: May 2011

From the perspective of fractal geometry, the irregularity and complexity of near-fault ground motions and seismic responses of single degree of freedom (SDOF) are analyzed. Based on the box-counting method, the fractal dimensions of 30 acceleration time series of near-fault ground motions from Taiwan Chi-Chi earthquake and California Northridge earthquake are calculated. It is indicated that the acceleration time series of ground motions present the statistical fractal property, and the influence of characteristics of near-fault ground motions on their box dimensions is remarkable. Moreover, the box dimensions of ground motions reflect their frequency property to a large extent, and can be regarded as alternative index to represent their frequency content. Finally, for the time histories of seismic dynamic responses of elastic and inelastic SDOF systems subjected to near-fault ground motions, their box dimensions are computed to examine the fractal property.
Seismic Vulnerability Analysis of Mid-Story Isolation and Reduction Structures Based Stochastic Vibration
Authors: Chang Pei Ju , Zhu Jian
Published: May 2011

This study focus on derivation of such fragility curves using classic mid-story isolation and reduction structures (MIRS) in China metropolis. A set of stochastic earthquake waves compatible with the response spectrum of China seismic code selected to represent the variability in ground motion. Dynamic inelastic time history analysis was used to analyze the random sample of structures. The result reveal that good effect for superstructure and reduction effect for substructure of MIRS is favorable and obvious under major earthquake, Weak position of MIRS was be pointed out and fragility curves of typical MIRS of China was obtained finally.
Surface Displacement of a Semi-Cylindrical Hill above a Subsurface Elastic Cylindrical Inclusion under SH-Wave
Authors: Lv Xiao Tang
Published: May 2011

Scattering of SH-wave by a semi-cylindrical hill above a subsurface elastic cylindrical inclusion in half-space is studied by complex variable function. Firstly, the whole solution domain is divided into two parts, and the solutions that satisfied the boundary conditions are constructed in two parts respectively. Then according to the “conjunction” condition of junction interface and the boundary condition around the subsurface elastic cylindrical inclusion, a set of infinite algebraic equations about the problem can be obtained. Finally the computational results of surface displacement were provided and discussed.
Analysis on the Influence of Dowel Bar at Joints on Load Stress of Pavement Slab in the Pumping Area
Authors: Yang Bin , Cheng Chung Tong , Huang Li Fang
Published: May 2011

A 3D finite element model is used to investigate the state of load stress developed in concrete pavement with dowel bar under the effect of typical pavement damages of pumping area of slab corner and pumping area of transverse joints edge. The results indicate that slab corner stress tends to decrease with the increase of slab thickness and possesses a nonlinear growth as pumping area increases; when the pumping area of slab corner is less than 1.5m×1.5m, the maximum pavement slab tensile stress is less than or close to the load stress in critical loading position. Stress in transverse joints edge also grows in a nonlinear tendency and axle load also grows gradually with the expansion of pumping area, of which the slope of the curve in the relationship between stress and void size is much greater. Whether it is a pumping area of slab corner or pumping area of transverse joints edge, pavement slab deformation and stress are significantly reduced after setting the dowel bar. Therefore, dowel bar can improve the stress state of concrete pavement obviously.
Experimental Analysis of the Slip Phenomenon of Sewage Sludge
Authors: Zhang Li , Feng Min Quan , Zhang Xiao Bin
Published: May 2011

Wall slip of sweage sludge and affect slip possible factors were studied experimentally by using a rotational rheometer with parallel plate fixtures and by means high speed camera. In the steady shearing flow, the technique involves placing a straight line marker monitoring of wall slip,checking the gap dependence of the stress/ strain data. For sweage sludge of water content 80%, in the shearing flow it was found that, as the strain amplitude increasing, the stress data obtained at different gaps, then, at the certain strain amplitude, started to diverge, indicating that wall slip occurred. But for sweage sludge of water content 90%, these curves are superimpose, indicating no slip occurred. In the dynamic oscillatory shear flow, we analyze the total wave. While strain, stress amplitude decreases with the time, while strain, the stress amplitude remains constant.
Performance Evaluation of BRA Modified Asphalt Mastic Based on Analysis of Microstructure and Rheological Mechanics Property
Authors: Wen Long , Wang Xiao Jiang , Liu Hao , Wu Hao Xiang , Cui Bao Lin , Cui Xiao Yi
Published: May 2011

Buton rock asphalt (BRA) is possessed of both performance and economic advantages. In order to reveal the modification mechanism, X-ray diffraction experiment (XRD), X-ray fluorescence spectrum analysis and environmental scanning electron microscopy experiment (ESEM) are used to study on microstructure of BRA in this paper. It demonstrates that BRA can extremely adsorb free bitumen due to abundant microscopic pores, which consists of 70~80 percent Buton rock (BR) minerals and 20~30 percent pure rock asphalt (RA). RA with high viscosity is strongly adsorbed internal and outer of the surface of BR, which has high alkaline pH, high crystallization and strong surface activity. Then a special microstructure named “RA~BR” blend with stable property and strong spalling-resistance capability develops. Meanwhile, dynamic stability rheology test (DSR) is employed to study on the rheological mechanics property of BRA modified asphalt mastic. The high temperature performance grade (PG) level of BRA modified asphalt mastic with different mixing content is determined. The reasonable mixing content of BRA in matrix asphalt is 20~30 percent. The research proves that BRA modified asphalt possesses wonderful high temperature stability and has broad prospects for pavement application.
Research on Modifier and Modified Process for Rubber-Particle Used in Rubberized Concrete for Road
Authors: Tian Shuai , Zhang Tong , Li Ye
Published: May 2011

This paper studies the optimum proportion of rubber-particles in rubberized concrete for road, tests the impact of 12 modifiers and their modified processes in rubberized concrete and discusses the function mechanism of the modifiers in rubberized concrete. Research indicates: the optimum proportion of rubber-particles in rubberized concrete for road is low mix-proportion (volume ratio<5%); inorganic salt as modifier can markedly enhance the bonding strength between rubber-particles used in road and cement and improve the physical properties of rubberized concrete, among which CaCl2 produces the most effect; but organic solution, acidic or alkaline solutions are not fit to be used as modifiers in rubberized concrete for road.
A New Calculation Method for Cracking Width of Beam with High Strength Rebar
Authors: Dong Chun Min , Guo Ke Dong , Sun Jia Jia
Published: May 2011

With the application of high strength concrete and rebar, the influence of concrete strength on cracking width of reinforced concrete beam with high strength rebar is becoming more and more important. To investigate the effect of concrete strength on cracking width of reinforced concrete beam with high strength rebar, the experiment including 6 simply supported T-beams with high-strength rebar and 2 beams with ordinary-strength rebar have been made. Then the relevant specifications advised in Code for Design of Concreter Structure (GB50010-2002) are revised according to the experiment results so as to considering the influence of concrete on cracking width. A new cracking width method considering the influence of concrete strength on cracking width for reinforced concrete beam with high strength rebar is proposed. Finally, the comparisons between predictions and experiment results have been conducted, which shown that the proposed new cracking width method agreed with experiment results well.
Microscopic Mechanics of Debris Accumulation Body with Expansive Fine Grain and PFC Numerical Simulation
Authors: Zheng Li Ning , Xie Qiang , Zhao Wen , Qu Meng Fei , Li Chun Hua
Published: May 2011

To study the influence mechanism of the excavation stability of the debris accumulation body by the expansive fine grain, it has used by Particle Flow Code, based on indoor test, the fine-grain expansive effect has divided into fine-grain intensity attenuation and volume expansion, and it has linear decreased down from the surface on the accumulation body. Based on the contrastive analysis between simulated result and traditional finite element, the Particle Flow Code is more accurate and true. The analysis result has suggested that when consider the expansive action, the damage model is changed into surface sliding from part slump, and the X-direction stress added 20kPa in the interior of the accumulation body, and the whole sliding force added 30% more or less. At present, the field excavation situation is consistent with the calculation result.
Influence of Connection Location on Dynamic Characteristics of Three-Towers-Connected High-Rise Building
Authors: Yuan Wei Bin , Wang Lie De
Published: May 2011

With the increase of the height, the lateral stiffness of high-rise buildings decreased. The high and flexible structures would have large movement when they are suffered lateral forces arising from earthquakes and winds. Compared with the ordinary high-rise buildings, the dynamic characteristics of the connected tall building will be changed by the connection; its seismic response and background of excitation are more complicated. Various finite element models with different connection location are established in order to find out the change of dynamic characteristics caused by the connection. According to modal analysis, the natural periods and mode shapes of different models are obtained. By utilizing the time history analysis method, El Centro earthquake wave was inputted, the seismic responses are obtained. The difference of results and summarized variation of dynamic characteristics with connection factors are analyzed. The results show that structural natural period and mode shape will be changed when the connection position changing. Under the seismic excitation, the change of location has little effect on the displacement time history and the maximum displacement, but the influences to the acceleration time history and the maximum acceleration value are obvious.
Load Spectra Development for a Heavy Traffic Expressway
Authors: Wei Jin Cheng , Yu Cheng , Ma Shi Jie
Published: May 2011

To study the traffic characteristic and axles load spectra of a heavy load expressway, WIM data was collected, axle configuration and vehicles classification was determined. The characteristic of truck traffic monthly distribution and the truck hourly distribution was studied and axle load spectra for major tuck types were developed. The results show that there were more than 30 truck types running on the expressway, the peaks of truck traffic monthly distribution was in April, September and December and the rush hour of the hourly distribution was at midnight. All major axles had a bimodal pattern of load spectra. The second peak of single axle was about 12 to 13 ton, tandem axle 14 to 22 ton and the tridem axle 28 to 32 ton. More than 50% of axles were overloading.
Study on Influencing Factors of Flow-Ability of Cement Asphalt Mortar
Authors: Li Yun Liang , Tan Yi Qiu , Ou Yang Jian , Wang Jin Feng
Published: May 2011

Flow-ability of CA mortar is characterized by fluidity, and the effects of the CA mortar fluidity according to water, time, and feeding sequence are studied. Studies have shown that the amount of the used of water affects the fluidity most, in which the suitable amount of water is between 0.23 and 0.28. With the time delay, the flow-ability of CA mortar is reduced. When mixed with SBR latex, the process of decay of the flow-ability is significantly reduced. Feeding sequence has great effect on fresh mixed CA mortar. In the mixing process, to avoid asphalt emulsion and cement dry material in direct contact, the speed of demulsification is reduced, which can effectively increase the flow-ability of CA mortar.
Application Study on High Modulus Asphalt Concrete in Bridge Pavement
Authors: Li Yun Liang , Tan Yi Qiu , Meng Liang
Published: May 2011

A type of high modulus asphalt was prepared by mixing modifier into SBS modified asphalt and used for confecting HMAC-16 high modulus asphalt concrete with finished product of modified asphalt from Liaohe oil field. This paper investigates pavement performance of high modulus asphalt concrete and its practical application in bridge pavement. Results obtained by application in practical project show that the high modulus asphalt concrete is provided with outstanding high-and-low temperature performance and water damage resistance which are suitable for bridge pavement.
Research on the Soil Slope Stability Based on Soil Strength Deterioration in Seasonal Frozen Areas
Authors: Ge Qi , Wu He , Gong Ya Feng
Published: May 2011

Soil slope is one of the main parts of the road engineering. The stability of the slope is an essential prerequisite to ensure the safe operation of road transport. In seasonal frozen regions, shallow landslide hazards in soil slopes usually happen, which pose a serious threat to road safety operations. During the melting process, there forms stagnant water lubrication between the melting soil and freezing soil interface, which constitutes the weak interface of landslide hazard. Special methods to form the freezing – thawing (F-T) surface is designed, and takes consider the interface strength as the foundation of experimental tests, then opening to research the soil slope stability. Safety factor modification of the soil slope is presented. The conclusions of this paper present well theoretical and applied value to the regional slope failure analysis.
Properties of the Saline Soil in Southern Xinjiang and Study on its Improvement Mechanism
Authors: Jia Lei , Yan Song Hong , Li Yuan
Published: May 2011

The causes and status of saline soil in southern Xinjiang are stated simply, and the properties of it are presented based on experiment. Much emphasis is laid on the improvement mechanism design and the scheme comparison. On this foundation, a series of tests are conducted. The functions of different subgrade fillers and the reasonable proportion of them are studied. The result reveals that improvement scheme II-3 can effectively decrease anion content in saline soil, and mixed with cement and active material fly ash, can significantly increase the strength of the soil mass, and decrease water involved in expansion and frost heave. The research findings can provide an economical and applicable reference to the solving of problems such as frost heave, salt expansion and melt sinking of the saline soil subgrade.
Bi-Objective Superior Combination Method of the Post-Construction Settlement Forecasting of Subgrade
Authors: Lai Tian Wen , Zhou Qi Yun
Published: May 2011

The more used forecasting method of post-construction settlement of subgrade is to analyze the measured data to determine the forecasting model parameters，and then use this model to forecast the post-construction settlement in actual projects. Currently used forecasting methods are Hoshino method, index curve method, hyperbolic method and so on, these methods have their advantages, disadvantages and applicability. To make the best use of the advantages and avoid the disadvantages, accordingly the combination forecasting method is proposed that can both comprehensive utilization the information provided in a variety of forecasting methods and also improvement of the forecasting accuracy. Then a superior combination forecasting model is established by the highest forecasting precision and the best forecasting stability. Taking the measured data of post-construction settlement of subgrade for example, comparison of fitting precision and forecasting precision of various forecasting methods , and show that the superior combination method has advantages of higher fitting precision, forecasting precision and their stability.
Discussions of Tire Ground Pressure Distribution Model
Authors: Li Yan Ru
Published: May 2011

Though there have been some experimental studies to discuss laws of grounding shape and grounding pressure, the acknowledged mathematics model has not established. In order to discuss the law of tire ground pressure distribution, pressure distribution models of round rectangles grounding shape and ellipse grounding shape are advanced differently. Parameters setting method and 3-D graph of different ground pressure distribution are presented, and expressions of ground area, mean ground pressure, most ground pressure and the normal stress on the ground are deduced. Results show that the grounding shape of tire is close to ellipse or rectangle as load varying, and the distribution of grounding pressure express convex or concave under different tire pressure and loading.
Coupling Pipes Car-Following Model with GM Model
Authors: Ge Ying En , Wu Na , Sun Bing Rong
Published: May 2011

This paper proposes coupling the Pipes car-following model with the GM model to formulate a new car-following model that can generate consistent separation distances between the leading and following vehicles. First, an example is given to show that the GM car-following model can lead to different separation distances at the same steady speed. Secondly, a new model is formulated by coupling the Pipes model with the GM model and it is shown that the only meaningful attractor of the new model is one producing consistent separation distances at the same steady speed. Furthermore, the relationship of those macroscopic traffic flow quantities inherent in the new car-following model has also been investigated. In the steady state, the resulting speed-density relationship is exactly the same as one derived from the Pipes model. In the dynamic case, the derived speed-density relationship is a partial differential equation. Numerical experiments are carried out to show that the new car-following model can generate consistent separation distances between the leading and following vehicles.
Multistate Traffic Flow Headway Fitting
Authors: Ding Heng , Chen Wu Wei , Zhang Wei Hua , Chen Jun Jie
Published: May 2011

Influenced by a variety of factors, such as driving skill, traffic composition, signal control, traffic management, and traffic environment and so on, the traffic flow characteristic parameter statistics embodies multi-state characteristic which is incapable to describe precisely by using a single distribution model. In order to fit the headway characteristic parameter of multi-state traffic flow, based on the denseness of mixture Gamma distribution, the data could be fitted more accurately with the method of expectation maximization algorithm and by means of controlling the number of branches under the condition of precision beyond 95%. Take actual survey data as the example, this paper compares the fitting errors of negative exponential distribution, Erlang distribution and mixture Gamma distribution and the result shows that the fitting result based on mixture Gamma distribution is closer to actual case.
Research on Collision Avoidance Method of Car Anti-Head-and-Rear Based on Safe Distance Model
Authors: Sun Zhong Liang , Wang Xiao Kan , Zai Shou Xiang
Published: May 2011

The present rear-end collision accident proportion on the road increases day after day, car collision avoidance system is more and more paid attention. Analysising the existing car collision avoidance system, we propose a car anti-collision algorithm based on safe distance model in this paper. This method takes the influence factors of safety distance for main parameters which fully considers the speed change and the acceleration change of the car 1 and the car 2. It may realize real-time information acquisition and warning judgment according to the state of car 2, the car could automatic braking if necessary. VB simulation shows that the algorithm can effectively avoid collision, also automatically maintain the distance between vehicles, and lay a foundation for further research on the unmanned car.
Test and Analysis of Noise Reduction Effect for Different Heights and Distances of Sound Barrier
Authors: Liu Yan , Yang Bing , Zhang Xiao Pai , Zhong Zhi Fang , Dong Hua Xin , Sun Hua Yun
Published: May 2011

Based on the comparative analysis on the low-noise road surface, noise reduction green belts, noise barriers and other noise reduction methods, the sound barrier is put forward as an important method for reducing the city road traffic noise. The noise reduction effects for different heights and different distances of the sound barrier are tested and analyzed through noise and vibration test and analysis system, the following conclusions can be drawn. At the same heights from the ground, the father the test points away from the noise barrier, the higher the sound pressure level will be; At the same distances from the sound barrier, the nearer the test points from the ground, the smaller the sound pressure level will be; All of the sound pressure level curves have basically the same variation trend and the main noise frequency band is from 160 to 1600Hz; In the high frequency range which is greater than 1600Hz, the sound pressure level decrease significantly, indicating that the sound barrier has better noise reduction effect for high frequency range. The results provide the basis for the design of the sound barriers.
Microcrack Evolution and Stress-Strain Relationship of Saturated Concrete
Authors: Zheng Dan , Li Xin Xin
Published: May 2011

The strength and stress-strain relationship of saturate concrete is investigated in this paper. The influence of moisture to concrete strength is assumed to be related to cement surface energy reduction by water. The initial elastic modulus of concrete is obtained by considering the deformation of both pore and microcracks in concrete. The stress-strain relationship is achieved with damage mechanics by comparing the damage evolution rules between dry and saturated concrete under external loading. The comparison between experiments and the results by the model proposed in this paper indicates a favorable agreement.
The Damage Characteristic Influence and the Seismic Measure Research on the Frame Structure by the Filler Wall
Authors: Yang De Jian , Mao Sai Lan
Published: May 2011

The paper analyses the damages of the frame structure with bottom weak layer considering of Wenchuan earthquake. The analysis result indicates the current design method "pure frame" is imperfect. The related research shows that important reason for the bottom weak layer’s breakage is the stiffness mutation which is caused by the filler wall. If we arranged partial shear wall structure in the bottom weak layer, the adverse effects of stiffness mutation will be decreased, and improve the seismic performance of the frame structure with bottom weak layer.
Influence of Flow Shallowness on Scour Depth at Semi-Integral Bridge Piers
Authors: Akib Shatirah , Othman Faridah , Sholichin Mohammad , Fayyadh Moatasem M. , Shirazi S.M. , Primasari Budhi
Published: May 2011

The paper presents the experimental study on the effect of flow shallowness on the scouring at semi-integral bridge piers. The experimental work was conducted in the Hydraulic Laboratory of University of Malaya. Out of 1020 data collected in the flow shallowness and time evolution experiments, 60 data were chosen at maximum scour depth to be analyzed. 30 data for sediment size of d50 = 0.8 mm and 30 data for d50 = 0.26 mm were taken at each side of the piers. The results showed that similar trend was produced for both sediment sizes, the depth of scour increased with the flow depth. Almost all of the data plotted gave the best correlation coefficient. The scour depth at the left and right side of the pier were almost averaged.
3D Finite Element Analysis on ChaHanWuSu CFRD Built on Thick Alluvium Deposits
Authors: Sun Da Wei , Wang Kang Ping , Yao Hui Qin
Published: May 2011

As a very popular dam style, more concrete- faced rockfill dams have been built in the world, but there is presently only a few high CFRDs with dam height more than 100m built on thick alluvium deposits. ChaHaWuSu CFRD with dam height 107.60m and the maximum thickness of alluvium deposits 46.70m, has been built in Xinjiang province, China recently. The excessive of displacement of foundation and dam body may lead to big deformation of peripheral joint and cause the failure of seal materials and produce water leakage. Therefore, 3D finite element analysis was carried out to estimate the deformation of dam. Firstly, 3D mesh including surrounding mountain and alluvium deposits was established by use of advanced grid discreteness technique. Secondly, Desai thin layer elements were adopted to model the interface between the face slab and cushion layer. Moreover, joint elements were adopted to model the joints between the face slab and plinth, plinth and connecting slab, connecting slab and connecting slab, connecting slab and diaphragm wall. Finally, large scales of equations solving method were adopted in the procedure thus the computer calculation time was greatly reduced. The calculation result was compared with the monitored deformation date of ChaHaWuSu CFRD. All in all, the above research will do much benefit to the CFRD design on thick alluvium deposits.
A General Time Domain Solution for the Waterhammer of Liquid-Filled Piping System
Authors: Yang Ke
Published: May 2011

The paper has obtained a unified final solution for the waterhammer equations. The proposed solution, covering all kinds of initial conditions and boundary conditions, has been proved to be written in the form of the d'Alembert's wave functions. The periodical influence of the initial conditions on the results is discussed. The proposed solution, with two kinds of algebraic equations containing only finite terms, is suitable for numerical calculation, convenient for programming and liable to dealing with complex pipe systems. An example has been given to show the use of the method. The skill to perform the inverse Laplace transform in obtaining the solution is different from the traditional ones and can be extended to use in many other problems including the FSI waterhammer problem.
Dynamic Elastic-Plastic Analysis of Reinforcement Geogrids Applied in High Earth-Rockfilled Dam Slope
Authors: Zhu Ya Lin , Kong Xian Jing , Zou De Gao
Published: May 2011

Considering the dynamic response of high earth-rockfilled dam, dynamic elasto-plastic analysis method for dam slope reinforcement with geogrids was set up. Based on this model, the paper analyzed the deformation and failure mechanism of dam slope, as well as the effect of connection, the length, the spacing and the stiffness of geogrid on dam with deformation. The results show that geogrids with high elastic modulus and proper extensibility will apparently reduce the deformation and imporve the stability of the dam slope. In the case of high dam slope, the reinforcement length of geogrids is supposed to be 2a (a is the slip surface length), and the spacing is 2m.
Investigation of Groundwater Potential in Melaka District of Malaysia
Authors: Shirazi S.M. , Hosen Imran , Sholichin Mohammad , Akib Shatirah
Published: May 2011

The paper assesses groundwater quality and productivity in Melaka, Peninsular Malaysia. 238 data set shallow boreholes, 20 data set deep boreholes were collected and continuous pumping test data were used to determine productivity of the aquifers. 68 water samples were tested for water quality. The productivity of the wells and the characteristics of the aquifer were evaluated by pumping test using both the constant discharge rate and steps drawdown methods. The potential of shallow groundwater is low with average discharge <5 m3/hour. The potential of deep groundwater is high category with average discharge > 20 m3/hour. The results show that 32% (538 km2) from total area of Melaka district (1650 km2) is low potential categories, 56% (922 km2) is moderate and 12% (194 km2) is high. Based on the chemical data, the quality of deep aquifer is fresh. Therefore, it is available for drinking water with minimum treatment.
Empirical Formula for Calculating Maximum Acceleration of Concrete-Faced Rockfill Dam
Authors: Zhou Hui , Li Jun Jie , Kang Fei
Published: May 2011

On the condition of different dam heights and different shapes of river valley, 3-D dynamical responses of concrete-faced rockfill dams subjected to different seismic intensity input are analyzed based on equivalent-linear model in this paper. The results show that on the condition of the same dam height and the base acceleration excitations unchanged, the position of the maximum acceleration on the axis of the top moves from the middle to the riversides symmetrically with the increase of the river valley width. For the narrow river valley, the position of the maximum acceleration which occurs near the riversides to the wide valley is on the middle of the axis at the top. The result negates the application of 2-D dynamical computation for wide valleys, and shows that for the seismic response of high concrete-faced rockfill dams, the seismic amplification factor along the axis should be given, except for that along the dam heights. Statistical analysis is also made to the seismic coefficient, and an empirical equation for calculating the maximum acceleration of the dam is provided, which provide an reference for the seismic stability analysis of rockfill dams using pseudo-static method.
Bearing Capacity and Mechanical Behavior Experiment on Large Diameter-Expanding Pile
Authors: Jiang Jian Qing
Published: May 2011

Combined with the pile foundation engineering of a super-large highway bridge, vertical static loading test of pile with expanded diameter was carried out. The pile’s load-settlement curves, axial forces of the different pile’s section and the pile-soil interaction friction were obtained from the test. The load transfer mechanism and bearing behavior of the pile with expanded diameter under vertical load were studied. The results show that the ultimate load of the testing pile is more than 6000kN. The pile-soil interaction of the pile with expanded diameter behaviors as friction pile, and the bearing capacity of the segment with expanded diameter accounts for 40% of the ultimate load. These studies provide important references for similar projects.
Experimental Study on Adhesion Strength of Freshwater Ice Frozen to Concrete Slab
Authors: Jia Qing , Tian Wen , Lu Yong Chao , Peng Xu Ming , Yu Jing Rui
Published: May 2011

The adhesion strength tests of freshwater ice frozen to concrete material were performed in a reservoir by the precise control-temperature unit of ice at five temperatures (-2 °C, -4 °C, -6 °C, -8 °C, -10 °C) and the displacement rate in a range of 10-4-100 mm/s. The fitting curve of the peak adhesion strength and ice temperature was presented. The test results show that the frozen adhesion strength is very sensitive to the displacement rate. The frozen adhesion strength reaches the peak value at the ductile-brittle transition region, and the region is close to the lower strain-rate with decreasing temperature. The transition region of displacement rate is 3.0×10-4-7.5×10-3 mm/s. The results provide some design parameters for reservoirs in cold regions.
Deep Sliding Stability Analysis of Gravity Dam Based on FEM Strength Reduction
Authors: Guo Li Na , Li Tong Chun , Lu Shan Shan , Guo Ya Jun
Published: May 2011

Anti-sliding stability in deep foundation of Shatuo gravity dam is studied in this paper. Combined with the static and dynamic analysis of anti-sliding stability in deep foundation of gravity, strength reduction finite element method is used to do static calculation of anti-sliding stability firstly. The horizontal seismic strength can be gotten in order to be applied to the baseplane based on response spectrum method, thus dynamic calculation of anti-sliding stability can be carried out. The calculation result shows that static and dynamic anti-sliding stabilities in deep foundation of gravity meet the requirements.
A New Non-Stationary Stochastic Seismic Ground Motion Model and its Application
Authors: Wang Zhi Hua , Gu Chong Shi
Published: May 2011

Considering the uncertainty and the time variation of frequency contents of real seismic excitation, a new versatile stochastic strong ground motion model named general stochastic seismic ground motion (GSSGM) model is presented in this paper. Some essential assumptions for the earthquake process used in this paper are first given. The intensity and energy of the target seismic ground motion are used to determine the model parameters. The frequency contents are demanded to be agreed with the main characteristics of the target ground motions. The GSSGM model is appropriate to simulate the stationary, intensity non-stationary and fully non-stationary stochastic processes. Additionally, a simple non-stationary stochastic seismic response analysis procedure based on the GSSGM model and the pseudo excitation theory is put forward. The presented non-stationary stochastic seismic response analysis procedure is later applied in the seismic response analysis of a real homogeneous earth dam. The non-stationary analysis results display the effects of non-stationarity on the seismic response of the dam and reflect the main phenomena of dynamic embankment-foundation interaction. The results indicate that the GSSGM model and the presented analysis procedure are effective.
Study on Non-Depositing Critical Velocity of Water Delivery in Pipeline System under Different Conditions of Sediment-Laden Water Source
Authors: He Wu Quan , Cai Ming Ke , Zhang Ying Pu
Published: May 2011

Non-depositing critical velocity is an important parameter in project design for low pressure pipe irrigation system in irrigation districts of sediment-laden water resource. The velocity used to be calculated through the critical velocity equation for solid particles delivery in pipeline system. However, the calculation error is relatively large due to the small sediment content and the large fine-textured particle content. This paper conducted different non-depositing critical velocity experiments under 6 sediment concentrations and 4 pipe diameters. The impacts of sediment concentration, pipe diameter, particle size and distribution on the non-depositing critical velocity of water delivery in pipeline system were analyzed based on the experimental results.
Clogging Mechanism of Muddy Water Delivery Pipe and Technology of Anti-Clogging
Authors: Cai Ming Ke , He Wu Quan
Published: May 2011

Muddy river is the water source for most northern channel irrigation districts in China. Pipe clogging is the main problem to limit development of pipeline delivery irrigation technology in this area. The key to solve the problem is to determine the critical non-deposit flow velocity and the corresponding technologic measures. Based on part achievements of national “863” project, characteristic and operation of northern irrigation district , this paper analyzed the pipe clogging mechanism caused by muddy water and put forward a set of efficient pipe anti-clogging measures, which are confirmed to be practical through the application in a project.
A Study on PHC Pipe Pile Spur Dikes Three-Dimensional Finite Element Numerical Modeling in the Lower of Yellow River
Authors: Wang Zhong Fu , Zhou Min , Zhang Bao Shen
Published: May 2011

Based on the analyses of the traditional rockfill groins of spur dikes，the PHC pipe pile groin is presented.The functions of the riverwall protection function, anti-erosion performance, and structure design of the groin were analyzed. By the three-dimensional finite element numerical modeling, when the scour depth of spur dike is 20m, the safty coefficient of spur dike is 1.21 and the maximum deformation is 1.3 centimeter. The studies are shown that the PHC pipe pile have high strength, stability and anti-erosion performance; The deign of double-row pile is applied to the head of spur dike where the displacement is maximum and improves stress boundary condition of the spur dike and improves the whole stability effectively.
Shear Failure of Seabed Induced by Wave at the Chengdao Sea, the Yellow River Estuary
Authors: Chang Fang Qiang
Published: May 2011

The shear failure mechanism induced by wave of seabed at the Chengdao Sea was analyzed, one model to calculate the shear failure was established, and the factor of safety of shear failure at the different locations was calculated, some conclusions were gotten: (1) The shear stress at the seabed induced by wave and gravity along the submarine slope are the main triggers to cause shear failure, and the shear stress at the seabed surface induced by wave and currents can be ignored; (2) At extreme sea conditions, the shear failure regions are mainly distributed within the north-west and south-east. The shear failure depth of north-west area is within 4m, and that at south-east is relatively large, beyond 4m in depth. (3) The shear failure of Chengdao Sea was mainly controlled by wave stress in seabed. The shear failure region and depth calculated in this paper can be referred in oil engineering facilities design and construction.
The Selection and Numerical Simulation of Marine Engineering Floating Pier Structure
Authors: Liu Wen Bai , Su Ke Jia , Xi Shi Lei
Published: May 2011

As a type of very large floating structures，the design concept of the grid structure is applied to the marine engineering floating pier structure. The grid structure has many merits such as high structural strength, stiffness, integrity, lower weight and high degree of industrialization. A finite element software named ABAQUS is used to analyze the stress and strain of the marine engineering floating pier structure in the marine environment. The analysis shows that the structure meets the engineering requirements in structural strength, stiffness, stability and wave resistance.
Effect of Liquid Properties on the Reduction of N-Nitrosodimethylamine with Zinc(0)
Authors: Han Ying , Chen Zhong Lin , Shen Ji Min , Liu Yue
Published: May 2011

The effect of the common cations, anions and humic acid on the reduction of NDMA with zinc(0) was investigated. The NDMA removals were not the influenced greatly by the cations. All the anions depressed the NDMA final removal in the order of SO42-＜Cl-＜HCO3-=NO3-＜S2-. The humic acid of the varied concentrations inhibited the NDMA final removal. The initial NDMA removals were enhanced by several ions and the humic acid. The enhancements could be due to the promotion of the passive film breakage, the generation of reactive sites or the inhibition of the passive film formation. The final removal decrease may be caused by the diminishing reactive sites or the competing effects from the ions.
Treatment of Refractory Pharmaceutical Wastewater with Combined Bio-Technologies
Authors: Chen Zhan Li , Huang Xiao Hua , Sun Xian Rong , Liu Zhen Zhong , Zhan Jian
Published: May 2011

This unbiodegradable pharmaceutical wastewater is treated by the process of hybrid hydrolysis acidification technique (HHAT) with anaerobic-low DO condition and the hybrid aerobic bio-technology consisted of alternate-flow biological reactor (ABR) and two-way-flow biological aerated filter (TBAF). The largest plant in pharmaceutical wastewater treatment at home was built. The practice shows that the organics can be greatly removed and the effluent can reach the First Grade Discharge Standard which can be reclaimed with advanced treatment. The performance indicates that the treatment is stable.
Fractal Dimension of Floc Growth in Micro-Coagulation Stage II: Some Normal Influencing Factors
Authors: Li Hao Yu , Nan Jun , He Wei Peng
Published: May 2011

The coagulation experiment, with Kaolin as objects, aluminum chloride (PAC) as coagulant and hydrated MnO2 as coagulant aid, were accomplished under different conditions. In the experiment, the particle size distribution and turbidity in water were detected by on-line detector. The results show that increase PAC dosage, original turbidity, hydrated MnO2 dosage and coagulation time will make the fractal dimensions of floc growth in micro-coagulation stage increase. The fractal dimensions of floc growth in micro-coagulation stage increasing means more particle size <5µm flocs are removed. Hydrated MnO2 can strengthen micro-coagulation.
Effect of pH and Temperature on Coagulation Efficiency in a North-China Water Treatment Plant
Authors: Guan Di , Zhang Zhen , Li Xing , Liu Hui
Published: May 2011

This research focused on the effect of water temperature and pH to coagulation efficiencies in low turbidity water. And the optimum dose of coagulant was determined. Simulated the treatment processing, the organic matters and turbidity removal capacities of polyaluminum chloride (PACl) were measured in parameters of turbidity, CODMn and UV254 with different experimental conditions. The results indicated that the PACl optimum doses were 28mg/L. By increasing water temperatures in the range of 4°C～18°C, the turbidity removal efficiency was gradually enhanced, while the organic loading removal performed few correlations to temperatures. And the effective pH range was 6.0~9.0, that appeared greater influence on turbidity removal than organic loadings.
Application Research on Treatment of Micro-Polluted Raw Water in Winter Western Mountainous Cities Using Composite Coagulants of PAC-PDM
Authors: Xiang Ping , Zhang Nan , Jiang Shao Jie , Zhang Zhi
Published: May 2011

In this study, micro-polluted raw water in winter western mountainous cities was treated by PAC-PDM . The CCD model of response surface methodology was employed to investigate the removal rate of turbidity . Taken the model as constraint conditions and taken the minimum agent cost as the objective function, optimization model of composite coagulants is established. The results showed that when the turbidity was 1 NTU，the dosage of PAC (based on Al2O3) is about 26mg/L, and the proportion of optimization model of composite coagulant PAC-PDM is 5% and the dosage of PAC (based on Al2O3) is about 8mg/L. Therefore the dosage of PAC of the optimized composite coagulant could be decreased by about70%, and agent costs decreased by about 56% compared with those of PAC.
Experimental and Numerical Investigation on the Seismic Behavior of Large-Scale Beam to Column Exterior Joints with Composite Slab
Authors: Chen Shi Cai , Yan Wei Ming , Tian Xiao Ming , Gao Jie
Published: May 2011

In order to analyze seismic behavior of large-scale exterior joints of high-rise precast concrete structures, an experimental study on seismic performances of precast beam to column exterior joints with composite slab was conducted with large full-scale models. The failure pattern, hysteretic characteristic, skeleton curve, displacement ductility and energy dissipation, were analyzed. The results provided some information about the seismic behavior of the joint. However, due to the unique nature of the specimens, several other key parameters could not be varied. Therefore, a numerical joint model taking the bar slippage into consideration was developed based on the OPENSEES software and validated against the results of experimental test, then the parameters analysis was carried out. The study results indicated that the overall seismic performance of cast-in-place joint is almost equal to that of the monolithic specimen.
Experimental Research on Performance of Water-Cooled VRF System in Winter in Shanghai
Authors: Song Ying Qian , Fan Rui , Long Wei Ding
Published: May 2011

Water-cooled Variable Refrigerant Flow system (WCVRF) is like a connection of water source heat pump system and air-cooled VRF system and it has almost all advantages of both systems. For its better application in China, it is necessary to give a research and analysis through experiment firstly. So in the paper, the water-cooled VRF system is introduced firstly, then the practical experimental lab including test data point, system design and diagram in Tongji university is shown and explained clearly. Finally, through the analysis on test data such as inlet and outlet water temperature of unit, the power used of unit and water pump etc., we can see the instantaneous coefficient of performance (COP), seasonal COP and integrated part load value (IPLV) of whole system. All the results are helpful for the better application of water-cooled VRF system.
Hourly Heating Load Prediction of Radiant Floor Heating System Based on the BP Neural Network
Authors: Li Xiang Li , Lin Duan Mu , Wang Ren Jin , Wang Xing Wei
Published: May 2011

An improved error transfer BP neural network model is use to predict the dynamic heating load in a house or a dwelling unit with the character of hour heating load. Compared with the conventionally physical model, the computation consumption is reduced greatly for the less number of the parameters by improving the error transfer ways. The numerical simulation and experimental measure in a low energy consumption building of Dalian city are performed and the BP neural network model was based entirely on the field survey data. The results show that the simulated results are well agreed with the experimental data and the averaged relative error is less than 5%. Furthermore, this improved model can predict accurately hour heating load during the course of next 24 hours and it is favorable for predicting the short time heating load problems.