交通运输工程学报

Mechanical behavior of steel truss bridge stiffened with rigid cables in construction stage

LIU Yong-jian, LIU Jian, ZHONG Guan-xing, YANG Jian

Abstract: 3D finite element numerical method was used to simulate the whole construction processes of steel truss bridge stiffened with rigid cables.Changing boundary conditions and imposing compulsory displacements on some nodes were applied to simulate system transformation and internal force adjustment respectively.Relaxing the longitudinal stiffness of an end of longitudinal girder was applied to simulate the effect of slotted holes.The internal forces and deflections were compared under six main conditions.Analysis result shows that rigid cables can participate in action with steel trusses more effectively through system transformation and internal force adjustment.Through internal force adjustment in longitudinal and lateral directions, the deviations of internal forces for the chords of middle truss and side truss, as well as that of midspan and sidespan, are less than 5%.Slotted holes set at both ends of longitudinal girder can avoid it taking part in longitudinal action prematurely, through which the internal force and deflection of main truss would increase by about 10%, while the maximum combined compressive stresses of longitudinal girder and floor beam would decline respectively from-271.1 MPa and-505.8 MPa to-63.0 MPa and-178.0 MPa, which are less than their allowable stress value 210 MPa.More>

2009, 9(3): 1-10. doi: 10.19818/j.cnki.1671-1637.2009.03.001

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Shear buckling property of corrugated steel webs

DI Jin, ZHOU Xu-hong, QIAO Peng, KONG Xiang-fu, YU Kun, HOU Jian

Abstract: 16 different specimens of corrugated steel web were designed to study the shear buckling property of corrugated steel web, through changing the configuration parameters of corrugated steel web, including overall sizes, thickness and width of corrugated plate, height and angle of setback.Shear buckling test of the specimens were carried out in laboratory.Their structure deformations, stress distributions, shear buckling loads and shear buckling modes were obtained.The influences of above various parameters on the shear buckling loads and buckling modes were analyzed.Analysis result shows that according to the buckling features, the failures of corrugated steel webs with different configuration parameters can be classified into three kinds of main buckling modes.With the increases of overall sizes, angle of setback, thickness of corrugated plate, and the decrease of height of setback, the shear buckling loads of corrugated steel webs rise.The ratio of overall height to width makes little contribution to the buckling loads.More>

2009, 9(3): 11-18. doi: 10.19818/j.cnki.1671-1637.2009.03.002

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Triaxial shear test on anti-shear properties of asphalt mixture

ZHU Hao-ran, YANG Jun, CHEN Zhi-wei

Abstract: The anti-shear properties of asphalt mixtures were studied through triaxial shear test.The influence of shear fatigue on shear strength was analyzed by using triaxial repeated load test.The relationship between anti-shear strength index and rutting index was observed.Analysis result shows that such factors as gradation type, asphalt content, asphalt properties and test temperature have great influence on the anti-shear strength of asphalt mixture.Anti-shear strength decreases exponentially with the increase of repeated loading numbers.The relativity between anti-shear strength index and rutting index shows good logarithmic function.The main reason of rutting formation is flow deformation resulted from shear fatigue.More>

2009, 9(3): 19-23. doi: 10.19818/j.cnki.1671-1637.2009.03.003

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Performance experiments of high-modulus asphalt treated base

QIAN Zhen-dong, SHU Fu-min

Abstract: According to the material composition design of high-modulus asphalt treated base(ATB), the mechanical properties were analyzed through measuring their dynamic moduli and compression rebound moduli of high-modulus ATB, modified ATB and conventional ATB, and road service performances were studied through wheel rutting test, freeze-thaw split test, split test and fatigue test.Test result shows that various types of asphalts have relatively great influences on the dynamic moduli of ATBs.The compression rebound modulus of high-modulus ATB(AH-30) is 1.24 times as much as that of ATB-25(AH-70), and 1.19 times as much as that of ATB-25(SBS).Compared with other ATBs, high-modulus ATB has better high-temperature performance, water stability performance and fatigue performance, except for slightly poor low-temperature performance.More>

2009, 9(3): 24-28. doi: 10.19818/j.cnki.1671-1637.2009.03.004

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Fatigue performances of semi-rigid base course materials

SHA Ai-min, JIA Kan, LI Xiao-gang

Abstract: Four kinds of beam specimens with different structural types for four semi-rigid base materials were made by using vibration compaction method.The fatigue performance test of semi-rigid base materials was carried out by utilizing material test system(MTS).The results of the test were recursively analyzed by using Weibull's probability distribution function.A series of fatigue prediction models were set up.The effects of the structural types and flexural strengthes of semi-rigid base materials on their fatigue lives were studied.Analysis result shows that the recursive coefficients a and b of the models for the materials are different.The models of cement stabilized base course materials are tiny difference except framework-pore structure, and the scopes of a and b are respectively 0.969~1.110 and-0.073~-0.096.The scopes of a and b of lime-fly ash stabilized base course materials are respectively 1.129~1.173 and-0.079~-0.083.The logarithmic fatigue lives of framework-dense structure and suspend-dense structure are respectively 3.602 and 3.118 at 0.70 stress level, so the fatigue performance of the former is better than that of the latter.The logarithmic fatigue life of lime-fly ash stabilized macadam is 5.006 at 0.70 stress level, but the maximum value of cement stabilized base course material is 3.724, so the fatigue performance of the former is better than that of the latter.8 tabs, 11 refs.More>

2009, 9(3): 29-33. doi: 10.19818/j.cnki.1671-1637.2009.03.005

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Pavement performance of FYT waterproof

ZHANG Hong-jun, LI Zhen-xia, WANG Xuan-cang, WANG Ri-deng

Abstract: The basic properties of FYT waterproof were analyzed.Its specific technical indices were measured.Its optimum amount and optimum dosage range were determined by shear test and pullout test in laboratory.The influences of temperature, interfacial roughness and water on the pavement performance of FYT waterproof were studied systematically.Comparison test analysis for FYT waterproof and the others used in common were carried out.Analysis result shows that optimum spreading volume for FYT-1^# is 1.4~1.5 kg·m^-2, and that for FYT-2^# is 0.10~0.15 kg·m^-2.The shear strength and tensile strength of FYT at 25 ℃ is 7~2times of that at 60 ℃.The losses of shear strength and tensile strength of FYT are respectively 3.0% and 7.5% after soaking in water.Comparing with other waterproofs, except for synchronous crushed stone, its shear strength and tensile strength are 3~4 times of that of the others.Obviously, FYT has good pavement performance.More>

2009, 9(3): 34-38. doi: 10.19818/j.cnki.1671-1637.2009.03.006

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Finite element model of airport rigid pavement structure based on ABAQUS

ZHOU Zheng-feng, LING Jian-ming

Abstract: Based on ABAQUS software, the stress and deflection convergences of a slab with four free edges resting on Winkler foundation were analyzed.Appropriate continuum element type, mesh fineness and plane dimension for finite element model of jointed rigid pavement were studied.According to the concept of contributing areas, the stiffnesses of nodes along joint were distributed, and spring elements were set at corresponding points of abutting concrete boards to simulate force transfer among concrete boards.A comprehensive 3D finite element model to analyze the structural response of rigid pavement system was developed and verified.The transfer coefficients of joint loads for the model and a regress model were compared.Comparison result indicates that in the finite element model, second-order element C3D27 or C3D27R is most appropriate when considering interlayer contact.Relevant element dimensions should not exceed half of slab thickness.The maximum plane size of the model should be four times of relative stiffness radius.The element SPRING2 can be adopted to simulate the load transfer of joints in which stiffness are distributed to nodes based on their contributing areas.More>

2009, 9(3): 39-44. doi: 10.19818/j.cnki.1671-1637.2009.03.007

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Modified gray prediction model of service life for airport cement concrete pavement

WANG Guan-hu, CAI Liang-cai, SHAO Bin, ZHONG Xiao-lei, XU Ming-xia

Abstract: In order to accurately predict the service life for airport cement concrete pavement, the service characters of airport cement concrete pavement were studied, pavement breakage degree was considered as pavement service life index.A gray prediction model was established according to gray system theory.Its prescision was tested by using origin residual error method.The solving process of the model was improved by taking the latter measuring value of pavement breakage degree as initial condition.Analysis result shows that pavement breakage degree increases exponentially with service time, but pavement remaining service life decreases exponentially with service time.The relative error between the forecast value and actual value of pavement breakage degree is less than 5%, so the prediction model is effective and can be used in periodic inspectability pavement.More>

2009, 9(3): 45-48. doi: 10.19818/j.cnki.1671-1637.2009.03.008

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Dynamics properties of 2B₀ heavy haul locomotive based on longitudinal stress

XU Zi-qiang, LUO Shi-hui, MA Wei-hua

Abstract: To avoid the derailment accidents of 2B0 heavy haul locomotive in traction experiment, the principles of incline and stability for coupler under longitudinal stress were analyzed.The calculation principle of free angle for coupler was deduced.A dynamics model of coupler was set up according to the experimental data of coupler.Computation result shows that coupler's deflection under large longitudinal force is the main reason of the accidents.Coupler must have reset function to assure locomotive running security.The automatic reset ability of coupler and the characteristic of buffer have remarkable influence on the flange abrasion of wheelset.More>

2009, 9(3): 49-52. doi: 10.19818/j.cnki.1671-1637.2009.03.009

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Physical parameter identification method of vibration system based on minimum correction value method

ZHANG Li-min, ZHANG Wei-hua, DUAN He-peng

Abstract: Based on the orthogonality of the vibration modal matrix with respect to the mass and stiffness matrices for vibration system, the minimum correction values of physical parameters for vibration system were identified by vibration frequency and model.The optimization problem of vibration system with restrictions was solved by Lagrange multipler.A physical parameter identification method was proposed based on measured modal data.The formulae of physical parameter identification for holonomic and nonholonomic modal parameters were educed.An iterative arithmetic was given.The modal experiment and numerical analysis of a vibration system with 4 DOFs were carried out.Analysis result shows that the mass and stiffness matrices approach their real values, their maxmum errors are 0.34% and 0.086% respectively, so the method has high reliability.More>

2009, 9(3): 53-55. doi: 10.19818/j.cnki.1671-1637.2009.03.010

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Shift schedule of automatic mechanical transmission

CAO Ya-bin, LIANG Hai-shun

Abstract: In order to solve some problems existed in AMT vehicle, such as big shift impact and low shift success rate between gears which have large transmission ratio difference, shift schedule and shift quality were synthetically considered, and a new establishing method of down shift schedule was put forward.Down shift schedule was obtained based on the optimal power or fuel-economy up shift schedule when the impact value was controlled under 17.64 m·s-3 and down shift delay is in 2~8 km·h-1.An optimal power down shift schedule was developed for special off-road vehicle with the method, and the performance of AMT vehicle was compared with that of MT vehicle controlled by skilled driver.Analysis result indicates that the average acceleration of the former increases by 18.7%, the average velocity increases by 22.2%, so the power performance of the vehicle was improved obviously.More>

2009, 9(3): 56-59. doi: 10.19818/j.cnki.1671-1637.2009.03.011

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Simulation and optimization design on cylindrical pleated lube oil filter

FU Hai-ming, ZHU Jing

Abstract: In order to reduce the pressure drop of lube oil filter, the boundary simulation conditions of the pressure drop were confirmed by pressure drop test, and a 2D CFD(computational fluid dynamics) simulation model was put forward.The properties of the pressure drop and its influence factors were analyzed, and a multianalysis regress relationship was proposed.Simulation result shows that the influence factors are filtrating speed, fold height, routeway width, fold number, filter paper thickness and impurity concentration, whose influence degrees are from big to small.The relationships between the initial pressure drop and the influence factors but the thickness are nonlinear, besides, there is an optimal fold number.The correlative coefficient of the regress relationship is 0.998, so the relationship is credible.More>

2009, 9(3): 60-65. doi: 10.19818/j.cnki.1671-1637.2009.03.012

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Hardware-in-the-loop simulation of monitoring system for diesel engine based on dSPACE platform

DU Jian-wei, ZHANG Yin-bao, WANG Yin-yan, YANG Chuan-lei, ZHANG Peng-qi

Abstract: In order to reduce the development cycle and cost, dSPACE hardware-in-the-loop simulation platform was used in developing the monitoring system of diesel engine.BP neural network was used to improve the quasi-stable model of diesel engine.Matlab/Simulink was used to establish an improved quasi-stable model of TBD620V12 turbocharged diesel engine.The precisions of explosion pressure model and lubricating oil pressure model were inspected.The simulation model was operated in dSPACE operator, and the monitoring system was connected with dSPACE platform through I/O boards and interface circuit.The closed loop simulation of the monitoring system and turbocharged diesel engine model was carried out.The relative errors between simulation results and experimental data were less than 3%, so experimental verification can be substituted by the hardware-in-the-loop simulation, and the development cost and cycle of the monitoring system can be reduced.More>

2009, 9(3): 66-70. doi: 10.19818/j.cnki.1671-1637.2009.03.013

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Path-based solution algorithms of traffic assignment model considering emission

XIONG Wei, YAN Xin-ping

Abstract: The traffic assignment of non-additive path costs was analyzed.Emission effects on traditional traffic assignment model were considered.Based on Venigalla's research, a traffic assignment model considering emissions under different operating modes of engine was put forward.Two path-based algorithms such as gradient projection(GP) algorithm and disaggregated simplicial decomposition(DSD) algorithm were adopted to solve the mathematic model.Analysis result indicates that the CPU time consumed by GP is 1/25 of that consumed by DSD, the paths used by GP are 1/5 of that used by DSD, and both GP and DSD algorithms have rapider convergence speeds than Frank-Wolfe(FW) algorithm, so the path-based algorithms can be widely used in solving large scale traffic assignment problem with non-additive path costs.More>

2009, 9(3): 71-75. doi: 10.19818/j.cnki.1671-1637.2009.03.014

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Multi-user highway network equilibrium model based on generalized cost

XIA Xiao-mei, FAN Bing-quan

Abstract: In order to estimate traffic volume correctly, the influence factors of generalized cost which influenced the choice of traffic mode and route were analyzed.The components and function forms of generalized cost were studied.Multi-type vehicle conversion model was developed, and its adjustment factors were calibrated.With the theory and method of variational inequality, a network equilibrium model based on generalized cost was established by using the results of network equilibrium model for urban complex traffic.With transportation planning software Emme, an algorithm and program of the model was developed.According to the traffic data from Wenzhou City, some model parameters were calibrated.Analysis result shows that the traffic assignment result of the model is better than that of fractional step loading, especially in the case that the saturation value of road section is higher.More>

2009, 9(3): 76-80. doi: 10.19818/j.cnki.1671-1637.2009.03.015

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Spacial and temporal influences of emergency on traffic flow in large-scale activity

CHEN Qian, WANG Wei

Abstract: In order to study the dynamic characters of traffic flow in large-scale activity, the spacial and temporal influences and traffic management under emergency were analyzed, static multi-path traffic assignment algorithm and cell transmission model(CTM) were combined, and a quasi-dynamic assignment algorithm was proposed.A small network was simulated, the jam times of intersections were calculated, and the forming and dissipating characters of traffic jam under emergency were studied.Different effects of two traffic management schemes on traffic flow were contrasted.Analysis result indicates that the average vehicle delays of two schemes are 197 s·pcu^-1 and 232 s·pcu^-1 respectively, scheme I is better than scheme II.So quasi-dynamic assignment algorithm can quantitatively evaluate the effect of traffic management scheme under emerggncy.More>

2009, 9(3): 81-85. doi: 10.19818/j.cnki.1671-1637.2009.03.016

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Multi-runway collaborative scheduling optimization of aircraft landing

ZHANG Hong-hai, HU Ming-hua

Abstract: In order to make an efficient tactical decision in air traffic management, a collaborative aircrafts scheduling problem(CASP) was studied.Based on the idea of collaborative decision-making, an optimization model was proposed for CASP with interests of air traffic control(ATC), airlines and airports.With security constraint and equity constraint, the model minimized the total delay cost to find out optimal scheduling schemes.The equity constraint was set up by using Gini coefficient so as to deal with the relationship with efficiency.An idea of equivalent flight was introduced to analyze equity quantitatively.A genetic arithmetic was designed to solve the proposed model.Simulation result shows that compared with the computational result of first-come-first-served(FCFS), total delay cost is saved by 72.6%, maximal flight delay time is reduced by 50.8%, so the safety and efficiency of scheduling scheme are improved, and the proposed method is feasible.More>

2009, 9(3): 86-91. doi: 10.19818/j.cnki.1671-1637.2009.03.017

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Game model of flight seat inventory control in competitive environment

WANG Yu, SUN Hong

Abstract: Based on the analysis of domestic aviation market, the numbers of each airline's available tickets under different fare classes were regarded as decision variables, the seat capacity was taken as constraint, each airline's revenue maximum was taken as multi-objective function.A civil airline seat inventory control model in competition environment was set up, Lagrange multiplier method was used to solve the numbers of each airline's optimal low fare tickets, and the equilibrium seat was worked out.Simulation result shows that each airline's seat inventory control is restricted by each other and can arrive at equilibrium state.Due to the impact of passenger demand randomness, the model can achieve an equilibrium probability of 12.68% and a non-equilibrium probability of 87.32% in 12 000 simulations.The equilibrium is dynamic and hard to reach.The conclusions are consistent with practice, so the model is feasible.More>

2009, 9(3): 92-97. doi: 10.19818/j.cnki.1671-1637.2009.03.018

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Comprehensive-model method of reliability analysis for traffic accident reconstruction with redundant information

ZHANG Lei, LI Yi-bing

Abstract: In order to estimate the creditability of traffic accident reconstruction analysis, a reconstruction reliability analysis method was put forward which combined high-order moment technology, probabilistic perturbation method, Edgeworth series and reconstruction analysis technology.The confidence interval and confidence of reconstruction analysis result were obtained as the estimate indexes of the creditability.For traffic accident reconstruction reliability analysis with redundant information, a comprehensive-model method was proposed through integrating subjective weighting method, reliability analysis technology and optimization technology.A practical traffic accident case was investigated to verify the method's feasibility and validity.Study result indicates that the mean calculated by comprehensive-model method tends to the intermediate value of basic reconstruction analysis models, and the change range is minimum.So the reconstruction analysis result is more precise and scientific by using comprehensive-model method because of considering the intrinsical uncertainty influence of basic factors and expert experiences.More>

2009, 9(3): 98-102. doi: 10.19818/j.cnki.1671-1637.2009.03.019

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Fuzzy evaluation of BT financing risk for infrastructure building

WANG Yao-hui, MA Rong-guo

Abstract: The characteristics and classification of BT financing risks for infrastructure building were analyzed.A evaluation index system and a fuzzy-compositive evaluation model were set up.A method was put forward to confirm membership function.The BT project risk of Bigui Road and Ronggui Underground Road in Foshan City was evaluated by using the evaluation method.Evaluation result shows that the maximal membership degree of the project is 0.712 7, its risk belongs to the comment of the minimum risk, the test coefficient of validity principle for maximal membership degree is 2.728, which is more than 1, so the evaluation method is feasible.More>

2009, 9(3): 103-107. doi: 10.19818/j.cnki.1671-1637.2009.03.020

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Traffic control algorithm of emergency evacuation based on harmonizing intersection signal control and arterial access management

HU Hong, LIU Xiao-ming, WEI Heng, YANG Xiao-kuan

Abstract: In order to establish an efficient predetermined plan of emergency evacuation, the adaptabilities of SCOOT and BOTTLENECK algorithms were analyzed, and an optimal algorithm was proposed based on the integrating control of signal intersections and arterial accesses.New algorithm controlled signal intersections with SCOOT algorithm, and controlled entering traffic at arterial accesses with BOTTLENECK algorithm.In order to insure the routing priority of main evacuation direction, the two algorithms were optimized and integrated by controlling target delay strictly, meanwhile, the interference and delay of entering traffic were decreased, and the road net evacuation capacity under emergency state was excavated mostly.Simulation result indicates that with the optimal algorithm under emergency evacuation, the average travel time of vehicle is shorten by about 60%, and average speed is increased by about 1.5 times.So the efficiency of emergency evacuation is improved, and the algorithm is feasible.More>

2009, 9(3): 108-111. doi: 10.19818/j.cnki.1671-1637.2009.03.021

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Longitudinal and lateral coupling control for lane change

REN Dian-bo, ZHANG Jing-ming, CUI Sheng-min, ZHANG Ji-ye

Abstract: Based on vehicle longitudinal and lateral coupling dynamics model, the integrated longitudinal and lateral control for lane change in automated highway system was studied.Assuming the lateral acceleration meeted trapezoidal constraint, the desired yaw angle and yaw rate for lane change were derived by predetermined virtual trajectory, and the data of yaw rate can be measured with onboard sensors.With finite time sliding mode reaching law, the coupled lane change variable structure control law was designed.The stability of the control system was analyzed by using Lyapunov function method, and the sufficient condition ensuring the asymptotic stability of the control system was obtained.Simulation result shows that based on the proposed control law, vehicle has good track performance under various longitudinal velocities, and the track error is less than 0.06 m.More>

2009, 9(3): 112-116. doi: 10.19818/j.cnki.1671-1637.2009.03.022

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Edge detection algorithm of moving vehicle based on sequential image motion segmentation

ZHANG Da-qi, QU Shi-ru, SHI Shuang

Abstract: To obtain the shape feature of moving vehicle in interested region, a novel algorithm of edge detection was proposed.After inputting three consecutive frames with interested vehicle and stationary complex background, the motion region of vehicle was detected by image motion segmentation and median filtering operator.The complete region and enclosed contour edge of vehicle were gotten by displacing the left edge or the right one of the motion region in horizontal detection.The run time of the algorithm was reduced by enlarging the threshold of iterative equation for motion vectors.Experiment result shows that in a 30 min sequence of urban traffic, 95% of vehicles are accurately detected in complex background.More>

2009, 9(3): 117-121. doi: 10.19818/j.cnki.1671-1637.2009.03.023

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Probabilistic traffic forecast method based on comprehensive transport information platform

HU Hua, GAO Yun-feng, YANG Xiao-guang

Abstract: Taking the effects of traffic index release on traffic forecast into consideration, a procedure frame of traffic forecast was established based on comprehensive transport information platform (CTIP), mode matching method and probability statistics method.Two key implementation technologies were studied, including three-level traffic data fusion and traffic index release.Example result shows that probabilistic traffic forecast method reduces the saturation gap of main road and alternative road from 40% to 23%, improves the confidence of traffic forecast by considering the influences of traffic index release on travel behavior, and can balance OD distribution of road network effectively.More>

2009, 9(3): 122-126. doi: 10.19818/j.cnki.1671-1637.2009.03.024

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2009 Vol. 9, No. 3

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