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15 October 2014, Volume 33 Issue 5 Previous Issue    Next Issue

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Fixed End Method to Solve Shear Lag Coefficient of Continuous Box Beam Xiang Zhongfu, Jiang Junqiu, Huang Haidong 2014, 33(5): 1-6.  DOI: 10.3969/j.issn.1674-0696.2014.05.01 Abstract ( )   PDF (1066KB) ( )   Based on the superposition principle, a simple and practical calculation method to solve continuous box beam shear lag effect, that is, the fixed end method was proposed, which also met the accuracy requirements. The calculation formula of the shear lag coefficients of continuous box girder in constant load (even load) was derived. Through comparing with the results obtained from dissecting method, superposition method and finite element method, the proposed method turned out to be reliable and applicable, which was suitable for the calculation of the shear lag of thin walled box continuous beam. References | Related Articles | Metrics

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Distortional Effect of Trapezoid Single Box-Double Cells Composite Beams Zhang Yanling, Hou Zhongming, Li Yunsheng, Liu Peiye 2014, 33(5): 7-12.  DOI: 10.3969/j.issn.1674-0696.2014.05.02 Abstract ( )   PDF (1333KB) ( )   In order to reveal the distortional effect of the trapezoid single box-double cells steel-concrete composite beams, the distortional deformation mechanism was researched by the ANSYS software under the independent distortional loads which were decomposed from the eccentric vertical load, and the influence of diaphragms and slips at the bond surface on the distortional deformation were also analyzed. The main conclusions are that, the distortional deformation of the trapezoid single box-double cells composite beams includes the first anti-symmetric distortional deformation and the second symmetric distortional deformation; the end diaphragms can reduce the first distortional deformation and stress apparently, but have little influence on the second distortional effect; the diaphragm at middle span can decrease both the first and the second distortional deformation and stress obviously; the slip at the bond surface will increase both the distortional deformation and stress. So the end and middle-span diaphragms should be set in the trapezoid single box-double cells composite beams, but the diaphragms at other locations should be limited or deleted. And the slip at the bond surface should be considered in the distortional effect analysis. References | Related Articles | Metrics

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A Fine Calculation Method for the Main Cable Fabrication Length of Self-Anchored Suspension Bridge Han Xuhui, Yuan Yangguang, Chen Anyang, Zhao Jianfeng, Shu Tao 2014, 33(5): 13-16.  DOI: 10.3969/j.issn.1674-0696.2014.05.03 Abstract ( )   PDF (667KB) ( )   The unstressed length of the main cable is an important parameter that influences the finished state of bridge structure. At present, the calculation methods for the fabrication length of the main cable center strand have been well studied. Based on the previous studies, a fine calculation method for the fabrication length of the main cable was proposed. Firstly, the main cable was simulated by cable element and the unstressed length of the main cable center strand was calculated according to the finished state of bridge of target structure. Secondly, the unstressed length of each main cable strand was amended considering the actual spatial distribution of main cable at anchorage end and the cable saddle. Finally, the proposed calculation method was verified by taking a self-anchored suspension bridge as an example; meanwhile, the exact fabrication length of each main cable strand was given. References | Related Articles | Metrics

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Dynamic Characteristics of CFST Arch Bridge in Construction Stage by Tower-Cable-Arch Integration Modeling Zeng Yong, Tan Hongmei 2014, 33(5): 17-22.  DOI: 10.3969/j.issn.1674-0696.2014.05.04 Abstract ( )   PDF (1153KB) ( )   Due to the coupling effects between arch rib, cable and tower, only the tower-cable-arch integration modeling can simulate the true dynamic characteristics of concrete filled steel tube (CFST) arch bridges in construction. The current largest span CFST arch bridge — Hejiang 1st Yangtze River Bridge model (model 1) in the tower-cable-arch integration construction was established by finite element software ANSYS, and its dynamic characteristics were also investigated. And the dynamic characteristics of model 1 were compared with those of cable-arch model without the consideration of tower (model 2). Research results show that considering the tower effects, the fundamental frequency of model 1 drops by 12%, compared with model 2. Due to the coupling effects of arch rib and tower, the higher vibration modes of CFST structures are complex, the structure transverse stiffness are notably weak and CFST structures have the outstanding wind sensitivity; the high frequencies of two models are nearly close to a straight line. The change of cable forces has little influence on low frequency. References | Related Articles | Metrics

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Influence of Hydrodynamic Pressure on Seismic Response of Piers in Deep Water Zhang Jie, Zeng Jinming, Zhu Dongsheng 2014, 33(5): 23-28.  DOI: 10.3969/j.issn.1674-0696.2014.05.05 Abstract ( )   PDF (1119KB) ( )   Taking a deep water pier bridge as the research project, the linear and nonlinear analysis on hydrodynamic pressure on seismic response of deep-water piers were carried out by Morison equation and the radiation wave theory. The influence results of hydrodynamic pressure on seismic response of piers calculated by above two methods were compared and the difference was obtained. The results show that in both methods the hydrodynamic pressure increases the structure dynamic response of the piers, and the influence value obtained by the radiation wave theory method is lager than that obtained by Morison equation; nonlinear analysis methods to analyze the seismic response of the bridge should be used when deep-water bridges enter the nonlinear state under strong seismic response; adopting the hydrodynamic pressure in the specification is not safe when the water depth is larger. References | Related Articles | Metrics

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Warning Level of Large-Span Continuous Rigid Frame Bridge in Single Live Load Wu Haijun, Li Jun, Huang Youbang, Wang Qingzhen, Yue Shun 2014, 33(5): 29-31.  DOI: 10.3969/j.issn.1674-0696.2014.05.06 Abstract ( )   PDF (757KB) ( )   The status quo that the bridge security state was determined by the live load response was analyzed, and the idea that the operational state determining and warning of bridge structure were carried out by structure stress response in single live load was proposed. Based on the reliability corresponding with different live load effects, the idea that the live load standard values, frequent values and quasi-permanent values were designed as the live load threshold values of warning and judging was proposed. The stress distribution characteristics of Jiangjin Yangtze River Bridge in actual single live load were analyzed, and the warning threshold values were obtained by the calculation principle of the stress warning value in single live load, and the actual warning level of bridge in single live load was assessed. References | Related Articles | Metrics

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Bridge Crack Detection Based on Differential Equations Wang Jiawei, Yang Tingting, Jiang Wei 2014, 33(5): 32-36.  DOI: 10.3969/j.issn.1674-0696.2014.05.07 Abstract ( )   PDF (1361KB) ( )   Aiming at the shortcomings of time-wasting, high risk and cost in the traditional process of detecting the bridge crack, fractional differential theory and sobel operation were combined and applied into the image edge detection. Therefore, a novel bridge crack detection model based on fractional differential theory was obtained. The theoretical analysis and simulation results show that comparing with the current edge detecting methods, the proposed model not only can detect the edge features of the images better, but also can detect more texture detail information. Furthermore, the objective evaluation indexes, such as connectivity, false detection rate and missing rate, show that the proposed method is an effective edge detection method, which can better achieve the purpose of bridge crack detection. References | Related Articles | Metrics

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Bridge Crack Automatic Detection System Based on Stereo Vision Zhang Kaihong, Luo Lin, Yan Yu 2014, 33(5): 37-41.  DOI: 10.3969/j.issn.1674-0696.2014.05.08 Abstract ( )   PDF (891KB) ( )   Bridge crack is an important indicator for bridge safety evaluation. Aiming at the disadvantages of high error, high missing detection rate and poor real-time capability in the traditional detection method of bridge crack, the bridge crack automatic detection system based on stereo vision was designed, combining with the digital image processing technology. The system obtained the feature points’ coordinates through camera calibration, setting feature points and preprocessing the crack images, and then the binocular distance measurement principle was applied to measure the crack depth. Moreover, the length and width of the crack was calculated by the statistics of related binary image pixels. The experimental results show that the proposed system can accurately measure bridge crack’s length, width and depth online in real-time. References | Related Articles | Metrics

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Bridge Load Level and Consumption of T-Beam Prime Materials Zou Zhuyu, Wang Liping 2014, 33(5): 42-46.  DOI: 10.3969/j.issn.1674-0696.2014.05.09 Abstract ( )   PDF (923KB) ( )   The increment of the consumption of prime materials of the monolithic 30m span of the prestressed concrete T-beam model in the same safety reserve was obtained by improving the vehicle load level under the condition of unaltered stiffness. With the help of monadic linear regression and path analysis method, the quantitative relation between the consumption of prime materials (concrete, steel) of monolithic T-beam and the range of improving the vehicle load level was determined. The conclusion can help relevant departments to make decision about the plan of managing overloading and improving load. References | Related Articles | Metrics

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Epoxy Mortar and Concrete Bonding Performance of Subtropical Area Yan Guotai, Xie Jinqi, Huang Zhen, Chen Xinlin 2014, 33(5): 47-50.  DOI: 10.3969/j.issn.1674-0696.2014.05.10 Abstract ( )   PDF (621KB) ( )   Comparison tests and studies of different epoxy mortar were conducted under different working conditions, in order to ensure the bonding performance between the thin epoxy mortar grout layer and concrete bridge beams in the bridge deck pavement engineering at sub-tropical areas. The results show that the bonding strength of the primer of epoxy mortar will be affected when it is exposed to the strong sunshine; with the increase of exposure time, the bonding strength decreases significantly. However, the influence of exposure under the sunshine can be erased by grinding and cleaning the exposed primer surface. Moreover, the application of epoxy mortar without primer can ensure the bonding strength. References | Related Articles | Metrics

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Influence of Foamed Asphalt on Viscosity Reduction Based on Orthogonal Experiment Xu Dawei, Jiang Chunxiang 2014, 33(5): 51-55.  DOI: 10.3969/j.issn.1674-0696.2014.05.11 Abstract ( )   PDF (558KB) ( )   In order to study the viscosity reduction effect of the foamed asphalt under different foamed conditions, 70# conventional asphalt and SBS modified asphalt were selected to do the orthogonal experiment. After the studies on the viscosity of the foamed asphalt under different foamed conditions, the results are as follows: the influence degree of viscosity reduction of 70# conventional asphalt is water consumption＞foaming temperature＞foaming water temperature; its viscosity reduction effect is optimal, when the foaming temperature is 150 ℃, water consumption is 3% and the temperature of water is 20 ℃. The influence degree of viscosity reduction of SBS modified asphalt is foaming temperature＞water consumption＞foaming water temperature; its viscosity reduction effect is optimal, when the foaming temperature is 160 ℃, water consumption is 3% and the water temperature is 60 ℃. References | Related Articles | Metrics

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Heating Temperature Gradient and Machinery Operating Parameter Control of Asphalt Pavement in Hot In-Place Recycling Engineering Shu Qin, Hu Zhuyun, Ren Dacheng, Guo Xiaohong 2014, 33(5): 56-60.  DOI: 10.3969/j.issn.1674-0696.2014.05.12 Abstract ( )   PDF (677KB) ( )   Considering the heating problems of old pavement in the hot in-place recycling technology, the heating of asphalt pavement was calculated and analyzed, according to the heating theory of asphalt pavement and mixtures. The idea that asphalt heating temperature should set gradient in the hot in-place recycling technology was proposed, and the principles and methods of setting heating temperature gradient were provided. References | Related Articles | Metrics

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Application of Graded Siliceous Sandstone Liu Tangzhi, Huang Xichun, Zhang Jianwei, Li Junjie 2014, 33(5): 61-64.  DOI: 10.3969/j.issn.1674-0696.2014.05.13 Abstract ( )   PDF (776KB) ( )   According to the large differences of siliceous sandstones in physical properties, the feasibility of using siliceous sandstone as graded broken stone material was undertaken, which was based on Fu-Feng-Shi Expressway of Chongqing and the evaluation of their physical and mechanical properties through laboratory test. Secondly, the reasonable gradation types based on the CBR index were selected. Finally, the fine aggregate limestone was mixed with sandstone to get the graded broken stone and explore its interrelated properties. The results show that the siliceous sandstone rubble with low density and high water absorption can be used as the graded broken stone material; continuous gradation on the basis of CBR index is more reasonable; the strength of structure can be improved at a certain degree by blending fine aggregate limestone; the strength of graded broken stone is significantly influenced by fine aggregate with plasticity index under 0.075 mm and aggregate strength between 1.18 and 4.75 mm. The strength of graded sandstone is mainly composed of various levels of gravel packing. References | Related Articles | Metrics

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Effect of Vehicle Load on Semi-rigid Base Asphalt Pavement in the Early Stage of Open Traffic Liu Junqin, Ma Shibin, Chen Han 2014, 33(5): 65-69.  DOI: 10.3969/j.issn.1674-0696.2014.05.14 Abstract ( )   PDF (834KB) ( )   To explore the mechanical response of asphalt pavement structure under vehicle loads in the early period of highway open traffic, firstly, the road performance parameters of pavement material in 7, 14, 21, 28, 35d at 10 ℃ and 20 ℃were gained through laboratory experiments. Then the variation rule of vertical displacement, compressive strain and tensile stress under factors, such as age, axle load and temperature was calculated out by utilizing KENPAVE program. The correctness of the calculation results was verified by actual detection. References | Related Articles | Metrics

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Truck Dynamic Load on Uneven Pavement Wei Lianyu, Yang Zhenglong, Li Siqian 2014, 33(5): 70-72.  DOI: 10.3969/j.issn.1674-0696.2014.05.15 Abstract ( )   PDF (627KB) ( )   In response to the question of the relationship between the truck dynamic load and pavement structure mechanical response, the SM2000C dynamic weighing instrument was used to collect and analyze the test data of the actual dynamic load of the cars in the full load and overload situation with different speed on Cangzhou arterial highway. ABAQUS finite element software was applied to establish a three-dimensional pavement structure model for dynamic simulation using half-wave sinusoidal dynamic load, and the simulation results were compared with the dynamic load values measured by test. The results show that, the proposed model can well simulate the dynamic load changes of the truck crossing through a certain pavement structure, which can be applied to actual engineering. References | Related Articles | Metrics

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Source Apportionment of Pollution of the Main Stream in Three Gorges Reservoir of Chongqing Zhai Jun, Li Lingli, Xiao Haiwen, Yu Qiuyang 2014, 33(5): 73-76.  DOI: 10.3969/j.issn.1674-0696.2014.05.16 Abstract ( )   PDF (786KB) ( )   Based on the water pollution characteristics of the main stream in Three Gorges reservoir of Chongqing, eight typical water quality indexes such as CODCr, TP and NH3-N were selected. The water quality of the main river in the Three Gorges reservoir was evaluated by the multivariate statistical analysis method, the significant source apportionment and contribution rate of water pollution of the main river in the Three Gorges reservoir were quantitatively analyzed. It was proposed that there were three main kinds of typical water pollutants of “Three rivers” (Yangtze River, Wu River, Jialing River) mainstream in the Three Gorges reservoir of Chongqing, including aerobic organic pollutants, eutrophic pollutants such as N, P and pathogeny feces pollutants, whose contribution rates were 31.25%, 23.09% and 16.67% respectively. References | Related Articles | Metrics

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Step-Pool Flow Field Structure Characteristics Huang Huadong, Qi Lijian, Yu Guo’an, Chen Shehong 2014, 33(5): 77-80.  DOI: 10.3969/j.issn.1674-0696.2014.05.17 Abstract ( )   PDF (1105KB) ( )   Taking the natural step-pool system in mountainous rivers as the research subject, the numerical simulation method of k-ε turbulence was used to research the related properties between flow structure and energy dissipation of the bottom of step-pool under different flow rates. The experiment results show that the development of the step-pool recirculation zone has increased the time for water circulation in the deep pit district, promoting the dissipation of residual energy, which is extremely beneficial to the security and stability of the riverbed. In the pit area, in the process of mainstream converting into vortex, turbulence is extremely strong and energy is dispersed into the mainstream around quickly and uniformly, which prevents the riverbed from directly destroying by increase of energy. In addition, step-pool automatically adjusts the step-pool structure to adapt the different flow conditions situation and optimizes the structure, so that the flow of water becomes smoothly and the pressure distribution becomes uniformly, which improves the stability and safety of the structure. References | Related Articles | Metrics

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Contributing Rate of Slope Gradient to Landslide Growth in Qianjiang District of Chongqing Wang Huan, Pan Daihong, JinYancai 2014, 33(5): 81-84.  DOI: 10.3969/j.issn.1674-0696.2014.05.18 Abstract ( )   PDF (417KB) ( )   The landslide hazard is serious in Qianjiang district, and the slope gradient is an important factor that affects the development of landslide hazard. To make a quantitative analysis on the relationship between slope gradient and landslide development, the slope gradient was divided into 9 value intervals, and the contribution rates of different slope gradients to landslides’ number, area and volume were analyzed. The results show that slope gradient in the range of 15°～30° makes highest contribution to landslide growth, slope gradient in the range of 10°～15° and 30°～40° contributes secondly, and slope less than 10° and more than 40° contributes lowest. The results correspond with the actual situation, which can provide a reliable basis for landslide hazard zoning in Qianjiang district. References | Related Articles | Metrics

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Research Status and Trend of Debris Flow and Flood Disasters of Mountainous Highway Chen Hongkai, Tang Hongmei, Zhu Xiuzhu, He Xiaoying, Tang Lan 2014, 33(5): 85-91.  DOI: 10.3969/j.issn.1674-0696.2014.05.19 Abstract ( )   PDF (1120KB) ( )   Debris flow and flood disaster is the major geological disaster in highway construction and maintenance in China, with high frequency, wide distribution, serious damage and other basic characteristics. Based on the search and analysis of domestic and foreign research literature, the research status of flood disaster of mountainous highway debris flow could be generalized into four aspects, including the highway washout of flood, debris flow dynamics mechanism, evaluation of flood hazard of highway and highway flood prevention technology, and the research progress of every aspect was elaborated. Based on the reduction demand of mountainous highway debris flow disaster, the weaknesses of the current research were pointed out, such as debris flow erosion and debris flow sediment consolidation mechanism, mud-rock flow-silting road section, highway traffic emergency access technology at the roadbed gap of highway along river, damage mechanics mechanism of highway roadbed and bridges along river. Four directions for further research on reduction of flood disaster and debris flow disaster in mountainous highway were proposed, namely is, the dynamic characteristics of debris flow in complex medium, highway roadbed along river and bridges damage mechanics mechanism, highway road emergency traffic technology, emergency safety warning method, system and equipment of road damaged by debris flow disaster. And the main thought of each research direction was interpreted in detail. References | Related Articles | Metrics

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Application of Grey Renewal Model on Landslide Dynamic Monitoring Cai Jun 2014, 33(5): 92-94.  DOI: 10.3969/j.issn.1674-0696.2014.05.20 Abstract ( )   PDF (472KB) ( )   Grey system theory was used in the data analysis of landslide dynamic monitoring, and Grey Renewal GM (1, 1) Model was proposed to forecast the landslide. Least square was used to get the parameters of Grey Renewal GM (1, 1) model. Test methods were given to inspect the accuracy of the proposed model. According to the measured data of actual landslide, the analysis and prediction results of Grey Renewal GM (1, 1) model were compared with those got by the traditional GM model. Comparison results show that the Grey Renewal GM (1, 1) model is better than the traditional GM model in accuracy, fitting data and forecasting data. References | Related Articles | Metrics

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Optimum Design for Cross-Section of Gravity Retaining Wall Based on Reliability Ye Chenmao, Wang Fei 2014, 33(5): 95-97.  DOI: 10.3969/j.issn.1674-0696.2014.05.21 Abstract ( )   PDF (439KB) ( )   The traditional gravity retaining wall design didn’t take the randomness of design variable into account, which couldn’t achieve a unified effect of economy and safety. The gravity retaining wall design based on the reliability was introduced, which took the randomness of each design variable into account. The proposed design took the cross-sectional area of gravity retaining wall as the object function, and took the anti-slides, anti-tilts reliability and the section structure request as constraint condition. A general mathematical solver LINGO was adopted to optimize the design of the gravity retaining wall. Finally, the obtained results of section size not only met the requirements of bearing capacity, but also met the reliability requirements. Comparing with the traditional design, the proposed design gets both safety and economy benefit, which brings more benefit for the construction of the project. References | Related Articles | Metrics

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Effect of Shear Dilatancy Angle on Bearing Capacity of Foundation Hu Shijing，Yao Shenglei，Yu Miao 2014, 33(5): 98-101.  DOI: 10.3969/j.issn.1674-0696.2014.05.22 Abstract ( )   PDF (734KB) ( )   Based on the classical elastoplastic theory, the dilatancy equations of Mohr-Coulomb model was analyzed and reasoned by the non-associated flow rule. By using ABAQUS-nonlinear FEM software, the bearing capacity of foundation in condition of different dilatancy angles was imitated and computed. The results show that the bearing capacity of foundation increases with the increase of dilatancy angle. The range of the dilatancy angle (3/4～5/6)φ is given by using ABAQUS simulation, which can be useful for practical engineering. References | Related Articles | Metrics

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Modeling of General Road Impedance Based on Security and Time Kong Lingzong, Liu Benmin, Zhou Xiaohuan, Li Zhizhong 2014, 33(5): 102-106.  DOI: 10.3969/j.issn.1674-0696.2014.05.23 Abstract ( )   PDF (916KB) ( )   In the case of emergency, in order to improve the speed of rescue and achieve the fastest relief in disaster areas, the optimized route selection model in emergency situations is needed to establish. A model of general road impedance based on security and time was proposed, according to the characteristics of the road network in the case of emergency. To overcome the defect of the conventional road impedance model considering only time factor, the network security was introduced into the model, which improved the conventional road impedance model. Finally, the optimized path in the case of emergency was obtained by Dijkstra Algorithm. Combined with the actual rescue case, the optimized route selection model was established, which was proved to be more suitable for the actual rescue by comparison with the conventional path selection model. References | Related Articles | Metrics

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Information Sharing System of Traffic Congestion Based on TCP/HTTP Protocol Liu Zunmin, Qu Dayi, Chen Xiufeng, Chen Wenjiao 2014, 33(5): 107-110.  DOI: 10.3969/j.issn.1674-0696.2014.05.24 Abstract ( )   PDF (1001KB) ( )   In the identification of traffic congestion state, the original data acquisition usually adopted the floating car and road test equipment, which usually had large error and seriously affected the accuracy of various traffic analysis models. An information sharing system of traffic congestion based on TCP/HTTP was proposed, which could effectively integrate two kinds of information resources: the objective information data of the simulated floating car and traffic flow was collected by the TCP protocol; meanwhile, the subjective information data of traffic congestion state was uploaded by the HTTP protocol in real-time. The proposed information sharing system included traffic congestion information sharing collection, floating vehicle information collection simulated by intelligent terminal, traffic flow information collection of intersections, which could realize the function of remote calling schedule of the intelligent terminal. The proposed system can provide the most intuitive decision support for traffic congestion analysis. References | Related Articles | Metrics

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Data Fault Diagnosis Model Based on Data-Driven Lu Baichuan, Zhang Kai, Ma Qinglu, Deng Jie, Liu Quanfu 2014, 33(5): 111-115.  DOI: 10.3969/j.issn.1674-0696.2014.05.25 Abstract ( )   PDF (1161KB) ( )   During the process of fault diagnosis of traffic and bridge monitoring data, it was found that the fault information had a property of multi-scale, and sometimes part of it was covered by noise, so a data fault diagnosis model based on data-driven was proposed. In order to diagnose the fault, firstly, an improved wavelet threshold method was joined to remove most of random high frequency noises, which improved the data reliability. Secondly, the reconstructed signals were decomposed by multi-scale wavelet packet. And then, the model finished the mission of the fault detection and isolation by combining Wavelet Packet Energy Analysis and Principal Component Analysis. Finally, the proposed model was applied in a case study of bridge deflection data fault diagnosis. The results show that the model has many advantages such as lower fault and fail rate, and stronger anti-noise ability. References | Related Articles | Metrics

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Lane Marking Detection Method Based on Texture Feature Dang Hongshe, Guo Chujia 2014, 33(5): 116-119.  DOI: 10.3969/j.issn.1674-0696.2014.05.26 Abstract ( )   PDF (687KB) ( )   In order to improve the accuracy of the lane line detection, an accurate lane line detection method was proposed, according to the feature that the texture features in the foreground region of lane image information were clearer. Aiming at the corresponding texture features in the lane left by rut, the characteristic diagrams of 5 scales and 8 directions were obtained by Gabor transform analysis with different scales at different directions. The characteristic diagrams were fused and texture direction characteristic together with index value of each pixel was obtained. The direction index value of each pixel was used to vote for the vanishing point, and then the vanishing point of the road was determined. Furthermore, a sector scanning area was determined by the vanishing point, and the lane marking was positioned. At last, the equation was established. The experimental results show that the method has strong robustness in strong light, shadow and lane line cloak. References | Related Articles | Metrics

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Mobile Highway Transportation Monitoring and ManagementSystem Based on Cloud Computing Zhao Yan, Du Wenguang, Yang Yong 2014, 33(5): 120-123.  DOI: 10.3969/j.issn.1674-0696.2014.05.27 Abstract ( )   PDF (1130KB) ( )   Due to the loose cooperative relationship between enterprise, transportation service providers and the driver, so it is difficult to implement the active and real-time positioning of transport vehicles. At the same time, the investment of a monitoring and control system with wide coverage self-built by enterprises will be huge. In view of this, the mobile highway transportation monitoring and management system based on cloud computing was established, which achieved the active monitoring and management in goods transportation process and the real-time and convenient monitoring and management controlled by mobile phone with less investment. GIS map, LBS (Location Based Service), GPS mobile phone positioning and EDI electronic data interchange was the support for the system to build the cloud computing platform, which realized each function of highway transportation monitored and managed by mobile terminals and Internet terminals through the operation of operators. References | Related Articles | Metrics

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Demand Level Identification of Regional Passenger Transport Corridor Based on Ordered Probit Model Li Li, Ding Hongfei 2014, 33(5): 124-127.  DOI: 10.3969/j.issn.1674-0696.2014.05.28 Abstract ( )   PDF (1152KB) ( )   To ensure the rational allocation of regional passenger transport corridor capacity resources, the demand level was selected as the dependent variable, and personal income, trip purpose together with psychological preferences were selected as the control variables. Therefore, an Ordered Probit model for the passenger demand level identification was established. Based on the Chengdu-Chongqing passenger transport corridor survey data, a three-dimensional view of the effect of the control variables on the dependent variable within the transport corridor was depicted by the use of oprobit command of Stata software to achieve the parameter estimation and by means of interpolation technology of MATLAB software. The results show that the demand level recognition model can well reflect the demand level of tourists with different influencing factors. References | Related Articles | Metrics

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Multifractal Analysis of the Baltic International Tanker Routes Based on MF-DFA Method Han Huayi, Qian Bin, Wang Xuefeng 2014, 33(5): 128-133.  DOI: 10.3969/j.issn.1674-0696.2014.05.29 Abstract ( )   PDF (1006KB) ( )   The fractal theory is an extremely important and new non-linear research tool in the modern economics. It was chosen to be applied into the shipping finance creatively. Based on the daily revenue rates data of Baltic Dirty Tanker Index (BDTI) and Baltic Clean Tanker Index (BCTI), the crude oil and refined oil market were proved to have the multi-fractal characteristics through the method of MF-DFA. At the same time, further calculation of the generalized Hurst exponent about the BDTI and the BCTI was carried out, and the conclusion that refined oil market owned more obvious multi-fractal characteristics than the crude oil market did was drawn, which provided a new theoretical idea and direction for BDTI forecasting and risk management. References | Related Articles | Metrics

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Rationality Evaluation on the Road Engineering Project Security Xu Maozeng, Wu Ke, Liu Guangfeng 2014, 33(5): 134-139.  DOI: 10.3969/j.issn.1674-0696.2014.05.30 Abstract ( )   PDF (683KB) ( )   The current road engineering project security types were summarized from the perspective of the road construction enterprise. The rationality evaluation model on the road construction enterprise security types based on the fuzzy set, membership function and fuzzy statistical method was proposed. A numerical example was carried out to prove that the proposed evaluation model was feasible. The research results show that the bid security, performance security and quality security are rational; the migrant workers salary security tends to be rational, and others are thought to be irrational at present. In addition, the reasons why the irrational security types appear are analyzed and the improvement measures are also proposed. References | Related Articles | Metrics

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Acoustic-Vibration Prediction of Large Jacket Platform Jiao Ziquan, Sun Yonggan, Ma Jun 2014, 33(5): 140-146.  DOI: 10.3969/j.issn.1674-0696.2014.05.31 Abstract ( )   PDF (1698KB) ( )   Acoustic vibration software VA ONE was used to research the noise problems of large jacket platform, and the basic theories and methods of acoustic calculation (finite element method, the boundary element method and statistical energy analysis method) were applied to the platform noise study. Taking the features of the large-scale jacket platform into account, the noise prediction studies of the platform opening area and the living compartments were carried out respectively. Noise contours of the platform deck and the superscalar area were obtained by calculation, and corresponding measures were also proposed. The noise level of platform living and working compartments was obtained, two types of noise reduction measures for the typical cabin were proposed. Through the contrast, a noise reduction measure with stronger feasibility and better economy was found out. References | Related Articles | Metrics

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Study on the Energy Utilization Ratio of Vehicles Driving Conditions Based on the Chassis Dynamometer Zhang Peng , Chu Jiangwei 2014, 33(5): 147-151.  DOI: 10.3969/j.issn.1674-0696.2014.05.32 Abstract ( )   PDF (991KB) ( )   The foreign and domestic research status on driving conditions was analyzed and the function and composition of chassis dynamometer system were introduced and then the concepts of energy consumption, energy state and energy utilization ratio were proposed. According to the driving distance of vehicle under the acceleration, deceleration, uniform and idle speed conditions and the free driving distance, the different energy utilization ratio models were established and applied to the driving conditions in China. Moreover, the chassis dynamometer system was used to simulate actual driving conditions on road and measure the sliding distances of various speeds, thereby the free driving distance of corresponding speed was obtained and the energy utilization ratio under driving conditions in our country was calculated. The research results show that energy isn’t in full use. References | Related Articles | Metrics

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Thermal Structure Coupling Temperature Field of Heavy Duty Disc Brake Luo Tianhong, Wu Bude, Luo Wenjun, Huang Xinggang, Li Chunhong, Zhong Zhi 2014, 33(5): 152-156.  DOI: 10.3969/j.issn.1674-0696.2014.05.33 Abstract ( )   PDF (905KB) ( )   For the disc brake with features of good heat dissipation, heat fading and high stability, the plan that the disc brake was applied to the heavy-duty vehicle brake system was proposed. A thermal-structure coupling mathematical model of the disc brake, the three dimensional temperature field model and friction interface coupling model were established, considering the influence of temperature on the friction coefficient and expansion coefficient. Thermal-structure coupling finite element method was used to analyze the brake temperature field distribution rule under the condition of high pressure and the braking processes under different conditions were also simulated respectively. The results show that at the end of the braking, the temperature field of friction pair is distributed along the circumferential direction and it has large temperature gradient along the radial and axial direction. The maximum temperature has approximately linear relationship with load and braking initial velocity in braking process when the friction plate adopts high-temperature-resistant material. And the maximum temperature is affected by elastic modulus of friction plate rather than the braking speed. References | Related Articles | Metrics

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Research on Structure Optimization of Support Structure Based on Random Vibration Analysis Tang Bo 2014, 33(5): 157-160.  DOI: 10.3969/j.issn.1674-0696.2014.05.34 Abstract ( )   PDF (846KB) ( )   The support structure which can provide support stiffness and vibration damping is the key component for the normal work of electronic equipment in complex work environment. Based on finite element method,modal analysis and random vibration theory，the systematic dynamic model of the support structure was set up. Using the Lanczos algorithm, the modal characteristics of the system were obtained. The structural optimization design for the support structure was performed considering the actual random vibration incentives. It shows that natural frequencies are increased. Also, the dynamic stress and displacement response of the support structure become more uniform and reasonable. The stress concentration phenomenon is avoided. The method has certain theory and project application value. References | Related Articles | Metrics

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A Method for Estimating Equivalent Rotational Inertia of Chassis Dynamometer He Changyuan, Zhu Maotao, Wang Guolin , Zhang Shupei, Huang Xuan 2014, 33(5): 161-164.  DOI: 10.3969/j.issn.1674-0696.2014.05.35 Abstract ( )   PDF (627KB) ( )   In order to make the vehicles’ braking process on Chassis Dynamometer platform as far as possible consistent with that on the road, the estimation of equivalent rotational inertia was required to be as far as possible close to the true value. Considering redistribution of vehicle axle load in the braking process and selection of turning radius, a method for estimating equivalent rotational inertia was put forward. The proposed method was used for the calculation of front axle equivalent inertia and used for two wheel drum experiment, which was suitable for the analysis on electric vehicle braking energy recovery process. Through the comparison of results of bench experiment and real vehicle road test, the results prove the validity of the proposed method. References | Related Articles | Metrics

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Rationing Efficiency of Public Rental Housing in Chongqing Pan Yuhong, Lin Junwei, Sun Qi, Zeng Yiwen, Zhang Xinming 2014, 33(5): 165-170.  DOI: 10.3969/j.issn.1674-0696.2014.05.36 Abstract ( )   PDF (999KB) ( )   The first batch of public rental housing met a cold market in Chongqing. In order to improve the situation, the government lowered the public rental application requirements, which canceled the application requirement of income limit. The information was obtained by network collection and field research, and the rationing status of Chongqing public rental housing was analyzed. The unfavorable factors which affected rationing efficiency of public rental housing were obtained by the questionnaire. And the data was deeply investigated by SPSS software, which revealed the difference of different influence factors affecting different segments of the “sandwich class”. Finally, combing with the conclusions got by comprehensive empirical research, questionnaire surveys and data analysis, the corresponding measures and proposals were put forward to improve the rationing efficiency of Chongqing public rental housing. Moreover, some of the problems which should be noted in the future course of the planning, construction and rationing operation of public rental housing were pointed out. References | Related Articles | Metrics