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19 January 2024, Volume 43 Issue 1 Previous Issue   
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Transportation Infrastructure Engineering
Transportation+Big Data & Artificial Intelligence
Transportation Equipment


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Transportation Infrastructure Engineering

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Effect of Flange Size on Shear Behavior of Geopolymer Concrete T-Beams SONG Jianxiong1,2,3, MAO Yuguang1,2,3, LIU Yiwei1,2,3, SU Jie1,2,3, DU Yunxing1,2,3, SHI Caijun1,2,3 2024, 43(1): 1-9.  DOI: 10.3969/j.issn.1674-0696.2024.01.01 Abstract ( )   PDF (5310KB) ( )   To investigate the effect of flange size on the shear behavior of geopolymer concrete T-beams, the shear test under concentrated loading was performed on 1 conventional reinforced concrete (RC) and 4 geopolymer concrete (GC) T-beams with different flange sizes. The relative parameters of T-beam specimens such as the load-carrying capacity, deflection, rebar strains, failure mode and crack propagation were obtained by the test. The research results indicate that the GC T-beam has similar crack propagation, failure mode and shear capacity to the RC T-beam, but its stiffness and diagonal section cracking load are lower, and the strain of longitudinal bars and stirrups in the mid span is larger. By increasing the ratio of flange thickness to effective height of the cross-section from 0.24 to 0.48, the stiffness of GC T-beam increases, the strain of the longitudinal bars in the mid span decreases, and the shear capacity increases by 12.7%. The normalized shear behavior strength of geopolymer concrete increases by 25.3%. When the flange width exceeds twice the web width, the continuous increase of the flange width can reduce the strain of the longitudinal bars in the mid span, but the stiffness, shear capacity, and the normalized shear behavior strength of geopolymer concrete will no longer increase. The calculation results of design code ACI 318-19 and Eurocode 2 significantly underestimate the shear capacity of the GC T-beams, and those of GB50010-2010 are close to the test values. To better predict the shear capacity of GC T-beam, it is recommended to increase the shear force provided by the effective shear area of the flange in the calculation formula of shear capacity. References | Related Articles | Metrics

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Virtual Preassembly Technology of Steel Box Segment Based on PCL ZHU Aizhu1, WANG Jiameng1, PAN Wenming2，CUI Bing3, ZHU Hongping1 2024, 43(1): 10-17.  DOI: 10.3969/j.issn.1674-0696.2024.01.02 Abstract ( )   PDF (6635KB) ( )   In view of the shortcomings of virtual preassembly technology in current engineering applications, such as strong subjectivity, low-level automation, and complex data processing process, the PCL was firstly introduced to virtual preassembly technology of steel box segment based on point cloud data. Firstly, a set of control point extraction method from surface to line, and from line to point was designed according to the section characteristics of steel box segment. Secondly, based on the high-efficient point cloud processing algorithm in PCL, the initial point cloud data of the assembly segment was preprocessed, control point extraction and matching were then carried out, and the assembly error results were output. Finally, the algorithms used in virtual preassembly technology were connected in series to form a complete set of virtual preassembly program for steel box segment, achieving data input and result output. The proposed virtual preassembly technology was applied to the adjacent segments of a certain steel box structure bridge, and the calculated maximum assembly error of 1.22mm was compared with that specified in the code. The results show that the virtual preassembly technology based on PCL can effectively complete the preassembly work of steel box segments, with the advantages of accurate results and high degree of automation. The vertical displacement of the segment control point under the state of hoisting stress is in the range of 0.08~0.14mm. The results show that the control point coordinates obtained by factory scanning can be used to guide the actual engineering assembly. References | Related Articles | Metrics

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Rutting Resistance of Steel Slag Thermal Resistance Asphalt Pavement ZHANG Zhengqi1, ZHANG Jingye1, ZHENG Wenzhang1,2, XU Yufeng3, TAN Junqing3 2024, 43(1): 18-25.  DOI: 10.3969/j.issn.1674-0696.2024.01.03 Abstract ( )   PDF (3876KB) ( )   To study the effect of steel slag replacing natural aggregate on the rutting resistance of asphalt mixture at high temperature conditions, asphalt mixtures with different steel slag contents were prepared firstly by replacing basalt coarse aggregates with equal volumes of steel slag and their thermal physical parameters were tested. Meanwhile, the cooling effect of steel slag asphalt mixture were also evaluated by indoor equivalent heat radiation test. Then, the influence of different steel slag contents of asphalt pavement surface layer on the temperature field distribution was analyzed by using numerical simulation methods, and the creep parameters of asphalt mixture were obtained through uniaxial static creep test. Based on the above temperature field, the rutting analysis model was established to evaluate the rutting resistance of steel slag asphalt pavement. The results show that the addition of steel slag reduces the thermal conductivity and increases the specific heat capacity of asphalt mixtures, and the maximum range of change can reach over 40%. With the increase of steel slag content, the pavement surface temperature rises slightly, while the temperature at the middle and lower surface layer gradually decreases, and the cooling effect at 4 cm depth is the most obvious. When the content of steel slag reaches 100%, the temperature of pavement can decrease by 3.4 ℃ compared with that of pure basalt asphalt pavement. While, the rutting deformation of steel slag with 75% content of asphalt mixture is the smallest, decreasing by 43% compared with that of basalt asphalt mixture, which can effectively improve the rutting resistance of pavement. References | Related Articles | Metrics

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Road Performance of Oyster Shell Powder Asphalt Mortar YANG Bo1,2, ZHOU Bo1, CHENG Yihuan1, ZHANG Meng1, TANG Naipeng1,2 2024, 43(1): 26-30.  DOI: 10.3969/j.issn.1674-0696.2024.01.04 Abstract ( )   PDF (5960KB) ( )   Based on the “dual carbon” (carbon peak, carbon neutral) background, the feasibility of using oyster shell as asphalt mineral powder was explored by broadening the ways of oyster shell green waste utilization. Through the preparation of oyster shell mineral powder and microscopic characteristic analysis, it was found that, oyster shell powder had finer particles, larger specific surface area, rougher surface, lower density and better adhesion, compared with dolomite mineral powder. Furthermore, the road performance of oyster shell powder asphalt mortar under five kinds of filler-bitumen ratio conditions was compared by DSR, MSCR and BBR tests, so as to determine the optimal filler-bitumen ratio and construction temperature. The research results show that compared with dolomite mineral powder asphalt mortar, oyster shell powder asphalt mortar has better high-temperature resistance to rutting and mechanical stability. Although its low-temperature performance is slightly inferior to that of dolomite mineral powder asphalt mortar, it still meets the requirements of low-temperature crack resistance well. In consideration of excellent road performance, economy, and environmental friendliness of oyster shell powder, it has good application prospect in pavement construction and maintenance projects. References | Related Articles | Metrics

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Design Method of Asphalt Pavement Structure Parameters Based on Multi-scale Loading Test LI Jun1, HE Chao1, LIU Zhen2, 3, GU Xingyu2, 3 2024, 43(1): 31-38.  DOI: 10.3969/j.issn.1674-0696.2024.01.05 Abstract ( )   PDF (4030KB) ( )   Based on the typical pavement structure in Jiangsu Province, dynamic modulus and creep tests were carried out on SMA-13, SUP-20 and SUP-25 materials by changing the size of the specimen, temperature and load times. The results were coupled to a modified Burgers model and a user material subroutine model was developed in ABAQUS. Strain hardening and subroutine model were used to simulate indoor uniaxial tests, while rutting simulations were performed respectively on small and large scaled road loading tests. The results show that the dynamic moduli of the three kinds of materials increase with the increase of specimen size and decrease with the rise of temperature. The fatigue damage effect of SUP-25 is the most obvious, and the damage value reaches 0.419 after 5400 times of repeated loading. The error of subroutine simulation of uniaxial test is smaller than that of strain hardening model. The errors between rutting simulation and small and large scaled loading test results are 3.08% and 2.83%, respectively, indicating that the proposed model is effective in the application of both single-layer and multi-layer composite materials. The simulation results show that the deformation under 1 million cycles of high temperature loading in summer is 1.8 times that of normal temperature in spring. When the driving speed increases from 22 km/h to 120 km/h, the deformation decreases by 72.6%, the axle load increases by 100% and the rutting depth increases by 48.52%, indicating that vehicle overloading should be particularly restricted in low-speed sections in high-temperature areas. When the cumulative number of standard axle loading has exceeded 25 million, the rutting deformation has entered the accelerated accumulation stage, and the maintenance measures for the pavement structure should be taken in time. References | Related Articles | Metrics

Transportation+Big Data & Artificial Intelligence

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Summarization of Traffic Language ZHANG Xu1, YANG Xiaoguang2, PANG Yuhao3, LI Yingshuai3 2024, 43(1): 39-45.  DOI: 10.3969/j.issn.1674-0696.2024.01.06 Abstract ( )   PDF (4988KB) ( )   On the basis of organizing and analyzing previous literature on traffic language, the concepts of generalized traffic language and narrowed traffic language were put forward. Based on 1083 literatures published from 2012 to 2022, CiteSpace was used to conduct a visual analysis of the research on traffic language in China in the past ten years, including institutional cooperation network analysis, keyword co-occurrence network analysis, keyword clustering analysis and highlight word analysis. The research shows that in the past decade, the annual publication volume of traffic language literature in China has shown a slow growth trend. The research direction has gradually transitioned from the early concept of “intelligent transportation” to the intersection of computer science and other disciplines for in-depth research. The hotspots of traffic language research are concentrated in areas such as traffic sign detection and recognition and intelligent traffic signal systems. Finally, the future research trend is predicted through highlighting of key words. References | Related Articles | Metrics

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Optimization of Berth Allocation for Container Terminal Considering Sea-Rail Intermodal Transport HU Zuoan1,2,3, SUN Yan1, GENG Cheng1 2024, 43(1): 46-51.  DOI: 10.3969/j.issn.1674-0696.2024.01.07 Abstract ( )   PDF (1605KB) ( )   In the context of sea-rail intermodal transport, it is crucial to optimize the benth allocation of container terminal by taking into account the characteristics of port vessels and railway trains, in order to improve the efficiency of port operations. A berth allocation optimization model for sea-rail intermodal container terminals was established, taking into account resource constraints such as dock shoreline, berth depth, and quay bridges, as well as constraints such as ship service priority and preferred berths, and arrival and departure time of railway container trains, whose optimization objective was to minimize the dwelling time of ships in port and the penalty time of berth deviation. According to the features of the proposed model, an adaptive genetic algorithm was designed to solve the problem. The data of arriving ships within 48h of the planned period were selected for case study. Finally, the berth allocation scheme of sea-rail intermodal container terminal that met the requirements of ship service priority and berth preference as well as accorded with the train operation planning was obtained by MATLAB numerical experiment. The numerical experiment results show that under the condition of sea-rail intermodal transport optimization, the average waiting time of ships is 2.9 min, and the maximum waiting time is 11.4 min. At the same time, the distance between the berthing position of ships and the preferred berth is not more than 100 meters, which means the dwelling time of ships in the port and the difference between preferred berths are well controlled. This study can further optimize the berth allocation scheme of the sea-rail intermodal container terminal, which is conducive to improve the efficiency of the sea-rail intermodal container transshipment. References | Related Articles | Metrics

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Traffic Capacity Calculation Model of ETC/MTC Mixed Toll Lane at Highway Toll Plazas SHAO Changqiao，CHEN Yanqing 2024, 43(1): 52-58.  DOI: 10.3969/j.issn.1674-0696.2024.01.08 Abstract ( )   PDF (1063KB) ( )   The influence of the ETC vehicle proportion αE at the entrance of ETC/MTC mixed toll lane and the queuing length w of consecutively arriving ETC vehicles on the average service time tS of the mixed toll lane was analyzed. SHAKER model was modified, and the parameters of the modified SHAKER model were calibrated. A VISSIM simulation model was established to validate the validity of the modified SHAKER model. The relationship between the traffic capacity of ETC/MTC mixed toll lane and ETC vehicles proportion was analyzed and a traffic capacity estimation model for ETC/MTC mixed toll lane considering the average service time of vehicles was proposed and analyzed in comparison with the cosine function model. The results show that: the relative error ε between the calculated value of the modified SHAKER model and the simulated value of the VISSIM model for the traffic capacity of ETC/MTC mixed toll lane under different αE is less than 10%, which verifies the validity of the modified SHAKER model within a permissible range. The traffic capacity of ETC/MTC mixed toll lane increases as the ETC vehicles proportion entering the mixed lanes increases. Compared with the cosine function model, the proposed estimation model can better reflect the traffic operation characteristics of ETC/MTC mixed toll lane. References | Related Articles | Metrics

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Accessibility of Bus Network Based on Mobility Orientation WANG Dengzhong1,2, MA Dongfang3, FANG Bo3, WANG Rujie3, YUAN Chao1 2024, 43(1): 59-66.  DOI: 10.3969/j.issn.1674-0696.2024.01.09 Abstract ( )   PDF (5152KB) ( )   The current public transportation priority strategy mainly focused on the optimization of network accessibility, which improved the convenience of residents’ travel by improving the density of regional line networks and stations, while lacked consideration of public transportation resource scheduling and mobility orientation. In order to make up for the above defects, the process of bus travel was firstly divided into three stages, including riding, transferring and waiting. And a set of index systems and calculation methods of regional public transport accessibility covering three stages was put forward. Secondly, Pearson correlation coefficient was used to describe the correlation patterns between accessibility index and mobility level, and K-means clustering algorithm was used to divide the correlation patterns, mining the differences between urban areas and key accessibility elements oriented by mobility improvement. Finally, a case study was conducted by the proposed algorithm by taking Hangzhou City as an example. The research results show that the high accessibility of public transport does not necessarily lead to the improvement of mobility level. To address this inconsistency, regional strategies for the development of public transportation networks have been proposed. References | Related Articles | Metrics

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Improved Model for Arterial Coordination Signal Control Based on Bus Priority ZHAO Xin, LI Rui, FENG Lei 2024, 43(1): 67-74.  DOI: 10.3969/j.issn.1674-0696.2024.01.10 Abstract ( )   PDF (1439KB) ( )   Based on the bus signal priority strategy, the MULTIBAND model was improved, the weight coefficient, the lane clearance time and the minimum green-wave bandwidth were redefined. The control strategy of red light early cut-off or green light extension was implemented according to different phase release methods. On this basis, the speed and stop time of bus vehicles were considered, the constraints on bus vehicles were established and an improved model of arterial coordination signal control based on bus priority was proposed. Through VISSIM simulation, the proposed model was compared with the traditional arterial coordination signal control models. The results show that compared with the traditional coordination control models, the proposed model reduces the average delay of social vehicles by 4.77%, the number of stops by 3.77%, the average delay of public transportation vehicles by 11.35%, the number of stops by 2.06%, and the per capita delay by 7.22%. The proposed model also shows good results under different bus flow rates. References | Related Articles | Metrics

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Identification of Safety Risk Sources of Highway Driving Environment Based on Improved MobileNet ZHAO Shuen, GONG Zhikun, LIU Wei 2024, 43(1): 75-82.  DOI: 10.3969/j.issn.1674-0696.2024.01.11 Abstract ( )   PDF (11625KB) ( )   In order to detect the safety risk source of highway driving environment and provide the basis for intelligent control of highway risk source and real-time safety risk assessment in random uncertain scenarios, a safety risk source identification algorithm of highway driving environment based on deep convolutional neural network model was studied. By improving the output layer activation function and loss function of MobileNetV3, the number of risk source categories output by the network was increased from one to multiple, which solved the problem of identifying multiple risk sources in the same image. The spatial attention mechanism was used to enhance the feature extraction ability of the MobileNetV3 network, which solved the problem that the MobileNetV3 channel attention mechanism could not pay attention to the feature information of the risk source inside the channel and improved the model recognition accuracy. Through the channel pruning method to remove redundant expansion channel, the number of network parameters was reduced, and the prediction speed of the model was improved. The experiment results show that the proposed method can effectively identify the driving environment safety risk source, with a detection rate of 0.829, an average classification accuracy of 0.833, and a real-time detection effect. References | Related Articles | Metrics

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Optimization Method for Taxi Drivers Passenger Search Path Based on Trajectory Data ZHOU Dan1, SUN Jiayu2, GU Guobin1, ZHONG Chujie3, WANG Tao1 2024, 43(1): 83-90.  DOI: 10.3969/j.issn.1674-0696.2024.01.12 Abstract ( )   PDF (5471KB) ( )   Taxi passenger search path planning is an important measure to reduce taxi emptying rates. To efficiently solve the taxi passenger search path planning problem, a taxi passenger search path optimization method was proposed by considering three indicators: the probability of carrying passengers, the empty travel time and the regional supply/demand ratio. On this basis, the improved DBSCAN clustering algorithm and the grey comprehensive evaluation method were used to mine the hotspot areas of DiDi Express\\Select Vehicles and determine the target points for seeking passengers. The taxi passenger search routes were obtained by introducing a new rule of permanent labeling and two-way search improved Dijkstras algorithm. Finally, Didi order data from the core urban area of Chengdu were used to validate the proposed algorithm as an example. The results show that the improved Dijkstra algorithm has a faster shortest path search speed than Best-First, Foyle and other algorithms. Meanwhile, compared with common passenger search paths, the passenger search distance obtained by the proposed method is reduced by about 21.33%, and the passenger search time is reduced by about 22.16%. The proposed method can effectively guide taxi drivers to choose a better route to search passengers and provide effective guidance for taxi dispatching and urban transportation construction. References | Related Articles | Metrics

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Shortest Path Problem Considering Robust Cost and Absolute Regret ZHOU Heping, LI Wenjie 2024, 43(1): 91-98.  DOI: 10.3969/j.issn.1674-0696.2024.01.13 Abstract ( )   PDF (2332KB) ( )   In order to overcome the conservativeness problem of the robust shortest path obtained by the robust deviation method when dealing with the interval road network, the concept of absolute regret value was proposed by combing with the case study through analyzing the definition of robust cost and the reasons why the robust shortest path was too conservative. And the multi-objective shortest path model of the interval road network was established with the robust cost and absolute regret value as the objective function. According to the characteristics of the shortest path model, the Benders decomposition algorithm that separated the path decision variable and the continuous variable was designed, meanwhile, the effective path conforming to the proposed shortest path model was redefined on the basis of the judgment criteria of the traditional effective path. Furhthermore, the effective path constraint was introduced into the decomposed main problem model to accelerate the convergence speed of the algorithm. MATLAB was used to generate an interval road network with 29 nodes and 70 two-way traffic sections, and the proposed model and algorithm were simulated and tested. The results show that the shortest path model considering the robust cost and absolute regret value can find the shortest path that is not conservative and is robust at the same time in the interval road network and can effectively overcome the shortcomings of the robust deviation method. References | Related Articles | Metrics

Transportation Equipment

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Energy Management Strategy of Extended Range UAV Based on Fuzzy Logic CHEN Wei1,3,LIU Jianhong1, REN Yi1, TU Chuan1, YAN Zhiwei2 2024, 43(1): 99-106.  DOI: 10.3969/j.issn.1674-0696.2024.01.14 Abstract ( )   PDF (3829KB) ( )   By establishing mathematical models of the engine, generator, battery and cooling fan for an extended range UAV (unmanned aerial vehicle), the energy management strategy of the extended range hybrid power system was studied. According to the working characteristics of UAV, a composite energy management strategy based on fuzzy logic (fuzzy composite energy management strategy) was proposed and simulated by using MATLAB/Simulink. The research shows that compared with pure oil driven and composite energy management strategy driven UAV, UAV driven by the proposed fuzzy composite energy management strategy saves 8.1% of fuel consumption compared with pure oil driven one and 2.2% compared with composite energy management strategy driven one. Meanwhile, in terms of stability, the engine using fuzzy composite energy management strategy has a speed fluctuation of 50 r/min less than that driven by pure oil and composite energy management strategy, and the fluctuation frequency is also lower. References | Related Articles | Metrics

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Braking Performance Analysis of Drum MR Brake with Internal and External Fluid Flow Channel HU Guoliang，YING Shicheng， XI Xingsheng，SHU Huijie，YU Lifan 2024, 43(1): 107-115.  DOI: 10.3969/j.issn.1674-0696.2024.01.15 Abstract ( )   PDF (5409KB) ( )   To solve the problem of low magnetic field utilization rate of conventional magnetorheological (MR) brakes, a drum MR brake with internal and external fluid flow channels was proposed. By adding non-magnetic parts to the rotary sleeve and cylinder, the magnetic flux lines were meandering through six effective damping gaps in the internal and external axial flow channels, so that the brake could produce better torque performance without changing its external dimensions. The structure and working principle of drum MR brake with internal and external fluid flow channels were elaborated, and the magnetic circuit of effective damping gap under magnetic field was analyzed. Meanwhile, the mathematical models of braking torque and the temperature field were deduced and established. The simulation analysis of the electromagnetic and temperature field of MR brake was carried out by COMSOL software. According to electromagnetic field simulation, it is found that when the applied current is 2.0 A and the speed is 400 r/min, the braking torque can reach 100.69 N·m, and the torque dynamic adjustable range increases from 1.00 N·m to 29.69 N·m. According to temperature field simulation, it is found that the highest temperature under multiple emergency braking is 42.88 ℃, which is in line with the normal operating range of MR fluid. References | Related Articles | Metrics

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Construction Method of Truck Actual Working Condition Based on Clustering and Markov Chain ZHOU Yingchao1, WANG Baolin1, LI Lianqiang2, TIAN Ying1, MENG Xinrui1 2024, 43(1): 116-124.  DOI: 10.3969/j.issn.1674-0696.2024.01.16 Abstract ( )   PDF (5834KB) ( )   In view of the large difference in fuel consumption and other performance between the truck regulation working condition and the actual working condition, the vehicle networking platform was used to obtain the real vehicle driving data of the target sample vehicle, and the construction method of the actual working condition of the truck based on Gaussian mixture model clustering and Markov chain was proposed. The kinematic segments were classified by principal component analysis and Gaussian mixture model cluster analysis. In the class, the driving state was divided by the speed interval, and the Laplace Smoothing method was used to estimate the state transition probability. The Markov chain method was used to synthesize the candidate working conditions in the class, and the best working conditions in the class were selected to construct the actual driving conditions of the target truck. The results show that compared with the original data, the joint probability density distribution of velocity-acceleration of the constructed working condition is in good agreement, and the average relative error of the overall characteristic parameters is 4.32%. Compared with the measured fuel consumption per 100 km, the relative errors of the simulated fuel consumption under regulation and constructed working conditions are 26.33% and 4.86%, respectively. The constructed working condition has higher accuracy and can effectively reflect the actual driving characteristics and fuel consumption performance of the vehicle, which can provide conditions and basis for the refined design of the vehicle and the vehicle performance evaluation on the actual road. References | Related Articles | Metrics