Responsible Institution:The Ministry of Education of the People's Republic of China (MOE)
Sponsor:ChangAn University
Publisher:Editorial Department of Journal of Traffic and Transportation Engineering
Chief Editor:Aimin SHA
Address: Editorial Department of Journal of Traffic and Transportation Engineering, Chang 'an University, Middle Section of South Second Ring Road, Xi 'an, Shaanxi
Abstract: Vehicle running speed and pavement friction coefficient were considered as random variables. Two performance functions of vehicle skidding failures based on quality point model and considering roll motion were proposed, and the safety reliability of vehicle moving on curve road was analyzed. The skidding probability of each horizontal curve with limiting minimum radius recommended by Technical Standard of Highway Engineering (JTG B01—2003) was calculated, the failure probabilities of two performance functions were compared by varying pavement friction coefficient and vehicle running speed, and the reliability design flow of horizontal curve radius was presented. Analysis result indicates that skidding probability calculated by the performance function considering roll motion is larger than that calculated by quality point model, and truck is more vulnerable to skid than car on the same road environment. Vehicle is simplified as quality point, roll motion and vehicle type difference are ignored in the horizontal curve design, these are adverse to truck safety. 5 tabs, 6 figs, 17 refs.More>
Abstract: The Duncan-Chang models for subgrade and soil were used, the maximum settlement of joint subgrade surface was chosen as an objective function, and the sensitivity functions and most sensitive parameters of the models were studied in the joint condition of subgrade. The detection data of settlement plates in actual engineering were used to inverse relevant parameters. Differential settlements of subgrade surface after laying pavement structure were calculated by using relevant parameters. Analysis result indicates that modulus index n is the most sensitive parameter for E-B model of subgrade, and the model is also obviously affected by modulus coefficient kE. Damage ratio Rf is the most sensitive parameter for E-B model of soil, and the model is also obviously affected by kE. and n. Detection data of settlement plates buried on soil surface and embankment middle layer can be used to inverse the most sensitive parameters of the Duncan-Chang models. Calculated settlement curves of joint subgrade surface after constructionhave good comparability with actual measurement curves of similar engineering. The numerical simulation with inversion parameters can describe the settlement characteristics of subgrade in joint condition. 3 tabs, 10 figs, 14 refs.More>
Abstract: In order to find out the idle reasons of loess dam embankment culvert for highway, the calculation model of reservoir was established according to the geological boundary conditions of U-shaped gully for embankment upriver water storage. In out water modes were set up based on the characteristics of embankment in-out water. Pool level formulae were proposed based on seepage mechanics and evaporation theory. Water level was calculated with simulated embankment parameters from investigation and actual measuring, and was contrasted with the actual situation of embankment water storage. Analysis result shows that highway loess dam embankment is of upper limit water levels without drainage and the influences of mud and sand in normal rainfall, that are ideal average water level and upper limit peak water level. The upper limit water level is not related with storing time. The essence reason for idle culvert is that upper limit peak water level is less than the bottom elevation of culvert, and the effect of upper limit peak water level on balancing storage should be considered in actual design. 4 tabs, 9 figs, 16 refs.More>
Abstract: In order to study the impact effect of vehicle-bridge coupled vibration on highway double-deck steel truss bridge, contact point between wheel and bridge surface was regarded as fringe, vehicle-bridge coupled vibration system was divided into vehicle subsystem and bridge subsystem based on separation method. The motion equations of vehicle subsystem and bridge subsystem were established respectively by using virtual work principle and finite element method. Vehicle subsystem was connected with bridge subsystem through displacement coordination condition and the balance relation of vehicle-bridge interaction at contact point between wheel and bridge surface, and system response was obtained by using iterative method. A highway double-deck simply-supported steel truss bridge was taken as study case, 3D beam grillage finite element model was established by using ANSYS software, and the influences of vehicle speed, bridge damping, bridge surface roughness and different loading modes on vehicle-bridge coupled vibration were studied. Analysis result indicates that there is not very regular function relation between vehicle speed and the impact factor of highway double-deck steel truss bridge. The impact factors of internal force and displacement for all bars become smaller with the increase of bridge damping. Bridge surface roughness is an important incentive for vehicle-bridge coupled vibration, poor bridge surface can make vehicle vibration more intense, and can induce greater impact effect on the whole and part of bridge. When loading modes of single layer and double-layer are different, the whole dynamic responses of bridge change little, the local dynamic responses of bridge are more obvious, so local impact effect should be considered in the design of bridge.More>
Abstract: In order to research the debonding failure of reinforced concrete(RC) beam flexural strengthened with high strength stainless steel wire mesh, the debonding failure in the anchorage area of strengthened beam plate-end was taken as research object, Smith-Teng model was revised to calculate the debonding failure of beam strengthened with fiber reinforced plastics(FRP) or bonding steel based on anchorage tests at the plate-end of 8 strengthened RC beams. The calculation model of debonding bearing capacity at the plate-end of beam strengthened with high strength steel wire mesh was established. The debonding failure at the middle part of strengthened beam was taken as research object, the middle part between two nearby flexural cracks of RC beam was regarded as arithmetic element, the stress condition of steel wire mesh was analyzed, and the calculation models of bonding shear stress and debonding normal stress at the middle part of strengthened beam were deduced. The debonding criteria at the middle part of strengthened beam were proposed, and the models were validated. Analysis result indicates that the upper limit of the calculation model of debonding bearing capacity at plate-end equals 0.57, it is in accordance with test result. The difference between the value calculated by the model of debonding bearing capacity at the middle part and test result is approximately 3.77%, so the calculation model is feasible.More>
Abstract: Based on the wheel/rail contact model of Polach's large creep theory, the creepage corresponding the saturated adhesion coefficient was determined in the brake condition of wagon. As block pressure was taken as the optimization objective and the creepage was taken as the objective function, vehicle dynamics model was built in SIMPACK environment under considering braking system. By ARX system identification, the reference system of creepage response was modelled in SIMULINK environment. On the purpose that the creepages of MBS model and reference model kept consistent during the brake, the creepage response was tracked by using MIT adaptive control technic, and an optimized method to apply block pressure was obtained. Compared with other ordinary methods, the optimized method decreases 71.6% of the maximal creepage and 11.8% of vehicle velocity at braking end, which can effectively eliminate wheel/rail slide and shorten the brake distance to a certain extent.More>
Abstract: Multigrid method was introduced into the calculation of wheel/rail adhesion under wet condition at high speed, and the influence of train speed and contact pressure on water film thickness was investigated under wet condition without thinking about surface roughness. Numerical analysis result shows that surface roughness and water film thickness have same order, and surface roughness is not ignored. Partial lubrication theory was applied to study the contact characteristics of wheel and rail under water lubrication based on the numerical analysis result, and the relationship between train speed and adhesion coefficient was investigated. Computation result indicates that with the increase of train speed, adhesion coefficient decreases rapidly, and its values are below 0.1. The comparison of experimental result obtained by JD-1 testing machine at the simulation speeds of 60, 90 and 120 km·h-1 and numerical analysis result shows that the maximum relative error of adhesion coefficient is less than 8%, so the numerical analysis method is accurate to estimate adhesion coefficient.More>
Abstract: In order to accurately control the safe berthing of large ship, the characteristics and berthing process of large ship were analyzed, the mathematic model of its auxiliary berthing instrument was established, and the berthing instrument and its display system of software terminal were designed. The two-point position differential global positioning system(DGPS) technology, automatic identification system(AIS) technology and wireless fidelity(WiFi) technology were used to complete the design of berthing instrument and the data transmission, and the berthing mobile data including the relative distances and speeds between bow, stem and wharf, the heading and the steering rate were calculated, which were sent via WiFi to the software terminal for the pilots to guide the safe berthing and unberthing of ship. Test result shows that the berthing instrument's horizontal positioning accuracy is 60 cm, the speed precision is 5 cm·s-1, and the data refreshing frequency is 5 times·s-1.More>
Abstract: Under the alternating loads, the strain gauges were arranged on the test pieces' surfaces of airfoil web, the stresses and strains of test pieces were recorded, and the sizes and positions to fatigue damage in the test pieces were detected by X-rays. The positions and damage severities of test pieces were determined, and the crack growth lifes of airfoil structural parts were predicted. Test result shows that the fatigue lifes of test pieces are approximate one million cycles under 40 kN sinusoidal alternating compression load, and they are in good agreement with the expected distribution of fatigue life(ten thousand-one million cycles). The stresses and strains from fatigue test and theory calculation are similar in variation trends, and the errors are about 10%. The high load and the moment around x axis cause the rivet failure and sheet fracture of test pieces, and the predicted fatigue crack growth life is 10 183 cycles.More>
Abstract: In order to improve the operation performance of large busy airport, some factors of multi-runways such as operation condition and safety requirement were considered. The minimum total flight delay was taken as objective function, the maximum position shift was taken as constraint condition, receding horizon control(RHC) strategy was introduced, and the dynamic flight sequencing model was established. Aiming at the characteristics of flight scheduling problem for multi-runways, the model was solved by using the genetic algorithm based on RHC strategy(RHC-GA) and the existing first come first serve(FCFS) algorithm respectively. Calculation result shows that when flights are normal, the total flight delay is 1 712 s by using FCFS algorithm. The total flight delay is 1 080 s by using RHC-GA, and reduces by 37.0% compared with the result of FCFS algorithm. When flights are not normal, the total flight delay is 1 658 s by using FCFS algorithm. The total flight delay is 969 s by using RHC-GA, and reduces by 41.5% compared with the result of FCFS algorithm. So RHC-GA is effective.More>
Abstract: The characteristic of location problem for mobile warehouse in express demand region with high strength was studied. The minimum total construction scale of mobile warehouse was taken as objective function, the region demand and service ability of mobile warehouse were taken as constraint conditions, and the meeting ant colony optimization(MACO) based on the set-covering problem of multiple granularities was put out. The demand points were regard as virtual particles, and K-means algorithm was used to cluster the particles. The preparation points of mobile warehouse were got from the divided particles, and the example verification was carried out by using traditional ACO and MACO respectively. Calculation result indicates that while traditional ACO is used, the computing time is 12.714 4 s, the optimal solution number is 13, the most poor solution number is 15, the average solution number is 13, and the correct rate of solution is 79%. While the proposed MACO is used, the computing time is 3.806 4 s, the optimal solution number is 12, the most poor solution number is 13, the average solution number is 12, the correct rate of solution is 98%, the construction number of location scheme for mobile warehouse is 12, and 10 preparation mobile warehouses are unnecessary.More>
Abstract: In order to evaluate the continuity of guide sign information in road network, road network was categorized into two hierarchies according to the impact area of guide sign information, and the model of road network was set up based on directed graph theory. Considering the deployment of guide sign information and turning decision spot in the route, the guide information item coefficient and the setting ratio of guide information were introduced, and the continuity evaluation model of guide sign information was established. Analysis result shows that setting the guide information in the road network with two hierarchies can reflect the law and psychological characteristic for traveler during the road research process. When guide information is lost, the quintitutive evaluation of specific route continuity can be carricd out by using the turning probability selection characteristics of route decision spots. When both of guide information term coefficient and the setting ratio of guide information are larger than 50%, the route is better in continuity.More>
Abstract: The relationship between axle load and the service life of highway was analyzed. Based on the frequency domain model and time domain model of pavement roughness, vehicle dynamics model with four degrees of freedom was set up. Numerical simulation calculation was carried out by using Mathcad software, and the maximum dynamic loads of front and rear wheels under different conditions were obtained. The relationships among wheel dynamic load and vehicle velocity, wheel load and overloading, wheel load impact factor and overloading were analyzed respectively, the actual service lifes of highway under different conditions were forecasted. Analysis result shows that there are linear increasing relationships between wheel dynamic load and vehicle velocity, wheel load impact factor and vehicle velocity. When vehicle velocity increases from 10 km·h-1 to 100 km·h-1, wheel dynamic load increases by 2.5-3.1 times, and wheel load impact factor increases by 17%-20%. Overloading decreases wheel load impact factor, but increases the real maximum wheel load greatly. Under the condition of overloading 100%, the actual service life of highway will decrease by 96% while the bottom layer tensile stress of asphalt layer is taken as design index, and the actual service life of highway will decrease by 99% while the bottom layer tensile stress of semi-rigid material layer is taken as design index.More>
Abstract: In order to analyze the relationship between driver personal characteristics and vehicle velocity, the method of combining personal attribute survey and real vehicle test was carried out, and the vehicle velocity record data of 80 drivers were obtained. According to the ratio of over speed time and total travel time for driver, the section of over speed selection behavior for driver was divided into 4 small sections. By using disaggregate theory, the personal characteristics of driver such as sex, age, personality, education level and driving age were taken as influence factors, the 4 small sections were taken as alternative parts, the influence measurement model of the personal characteristics of driver on vehicle velocity was set up, and the sensitivity of each influence factor was analyzed based on elasticity theory. Analysis result shows that all the 6 elasticity values of sex, age, education level, corrected vision, professional driver, traffic accident occurrence are less than 1.000, so the above 6 influence factors are short of elasticity to speed selection behavior. In the 4 small sections, the elasticity values of driving age are 6.287, 3.211, 3.438 and 2.450 respectively, the elasticity values of personality are 1.249, 1.045, 2.033 and 3.672 respectively, the 2 influence factors are rich in elasticity to speed selection behavior, and their effects are significant.More>
Abstract: The equations describing the relationship of phase difference adjustment quantities were established for intersection before and after transition. Considering the allowable range of each intersection's signal cycle length in transition period, the single-cycle symmetrical adjustment transition algorithm and the N-cycle weighted adjustment transition algorithm were proposed based on the minimax principle of offset adjustment ratio. Analysis result shows that when the symmetrical adjustment transition algorithm is finished in one cycle, and the actual maximum adjustment of intersection phase difference is minimized. The weighted adjustment transition algorithm comprehensively consideres the allowable range of each intersection's transition signal cycle, and can make a coordinated control scheme rapidly and smoothly transit to a new coordinated control scheme after N transition signal cycles based on the minimum requirement of the maximum adjustment ratio of phase difference. Compared with other transition algorithms, the global optimization of phase difference adjustment for all intersections in control area can be realized by the weighted adjustment transition algorithm, which better satisfy the control demands of different signal intersections, so the weighted adjustment transition algorithm is more practical and has a broader application scope.More>
Abstract: The influence scope of variable message signs(VMS) was estimated, and a collaborative model integrated of traffic control and VMS was constructed. The route choice behavior of driver was impacted by VMS, and the development of network traffic flow was guided by VMS to the optimization distribution mode. The interception and shunt of network traffic flow were fulfilled by adjusting intersection signal parameters in traffic control to form an optimal traffic flow distribution mode. The model was optimized and solved by combining Frank-Wolfe equilibrium assignment and genetic algorithm. The model and algorithm were developed by using Paramics API. In the condition of network with burst disaster, the model and algorithm were verified by taking software Paramics as simulation platform and Zibo New District of Shandong Province as simulation network. Verified result shows that with the increase of road network saturation, compared with Synchro model, the effect of the model is more obvious in improving performance indexes of road network traffic flow, the ability promoting the stability of road network's traffic flow is stronger, and the equilibrium assignment ability of road network loading is better. When the evacuation of traffic flow for sudden disaster completes 80%, and the link saturations of road network are not more than 0.8, between 0.8 and 1.0, more than 1.0 respectively, compared with Synchro model, the evacuation times respectively decrease by 11.55, 21.84, 25.64 min, the evacuation speed respectively increase by 25.98%, 31.83%, 20.16%.More>
Abstract: The characteristics of short messages from automatic identification system(AIS) base stations to ships in the inland river and port were studied. The principles of waveform distortion and package error were analyzed when AIS field strength was declined. In the hardware-in-the-loop simulation platform, the relationship between message length and package error rate was analyzed, and the prediction model of package error rate was proposed. Combined with Hata-Okumura model, the maximum capacity for short messages sent from AIS base stations to ships was proposed in crowded channel. At last, taking the Shanghai Channel of Huangpu River as an example, using the proposed model, the maximum capacity was calculated and compared with the measured result. Comparison result indicates that the reliability of short message decreases with the increase of short message length and the decrease of fixed field strength. The number of AIS target ships communicating with AIS base stations meanwhile is limited. For the Shanghai Channel of Huangpu River, the calculated number of AIS target ship communicating with an AIS base station is 26 when the total AIS target ships is 625, and the measured value is 24, so the calculated value basically matches with the reality value.More>
Abstract: Based on the flight tests and subsequent studies of unmanned aerial vehicle(UAV), the opportunities and challenges of UAV in traffic information collection, processing and application were analyzed, and the application future of UAV in traffic planning and simulation, road surveillance, emergency dispatch, urban congestion analysis and so on was prospected. Analysis result shows that the traffic information collection method using UAV is effective for continuous traffic information collection and complements existing methods. Traffic information is automatically derived from UAV videos with the development of dynamic video processing technology. UAV traffic information can be used to study emergency responses, car-following, lane-changing behavior, traffic congestion and so on. However, the adaptability of UAV dynamic video processing technology needs to be improved. The research on car-following, lane-changing and traffic congestion using UAV information needs empirical testing. Some important research direction in the future includes the establishment of UAV-ground emergency communication and coordination system, and UAV-vehicle-road coordination communication system.More>