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19 March 2025, Volume 44 Issue 2 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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Optimization and Selection of Mechanical Properties and Structural Parameters of Twin-PBL Shear Connectors YAO Guowen1，DONG Yuhang1，YING Li2，HE Xuanbo1， WU Shuhang1 2025, 44(2): 1-9.  DOI: 10.3969/j.issn.1674-0696.2025.02.01 Abstract ( )   PDF (2546KB) ( )   The continuous rigid frame bridge with corrugated steel webs is a new type of bridge structure, which combines the high strength and strong deformation ability of steel and the good compressive performance of concrete. The detailed structure of its shear connectors has a decisive influence on the overall bearing capacity. In order to further explore the mechanical behavior of Twin-PBL shear connectors and further improve their mechanical properties through the optimization of detailed structure, a solid finite element model of a typical box girder segment with corrugated steel webs was established based on ABAQUS software. The mechanical performance of Twin-PBL shear connectors between corrugated steel webs and concrete roofs was studied, and the influence rule of the presence or absence of transverse through rebar structure on the shear performance of Twin-PBL shear connectors was revealed. The structural parameters of the aperture, thickness and transverse through rebar diameter of the perforated steel plate were further optimized and selected. The research shows that the setting of transverse penetrating steel bars in Twin-PBL shear connectors can reduce the shear stress of perforated steel plates and steel flange plates, and the penetrating steel bars can share part of the shear force of concrete tenons in the holes. Therefore, comprehensively considering factors such as material properties and manufacturing processes of perforated steel plates, the optimal opening diameter of Twin-PBL connectors with a cross-section height of 180 mm is 70 mm, the diameter of transverse penetrating steel bars is 25 mm, and the thickness of perforated steel plates is 28 mm. References | Related Articles | Metrics

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Dead Load Partial Safety Factor of Long-Span Suspension Bridge Based on Reliability Theory QI Dongchun1, CHEN Chulong2, DING Shaoling2, WANG Maoqiang3, BAO Yunfei4 2025, 44(2): 10-17.  DOI: 10.3969/j.issn.1674-0696.2025.02.02 Abstract ( )   PDF (1117KB) ( )   The statistical analysis on the dead load of ten domestic suspension bridges with spans exceeding one kilometer was carried out, and the statistical parameters of various self-weight dead load random variables were obtained. The self-weight dead load effect of suspension bridges was divided into three parts such as main cable self-weight effect, stiffening girder self-weight effect and bridge deck system self-weight effect. The calculation formulas of partial safety factors for each dead load were derived on the basis of the optimization method, and the iterative algorithm was established. By calculating and analyzing various combinations of different live-to-dead load ratios and different dead load proportions, the valuing ranges of partial safety factors for each dead load and the equivalent partial safety factor for all dead loads were obtained. The research results indicate that the live-to-dead load ratio has a relatively small impact on the partial safety factors of the dead load, while the proportion of each dead load has a relatively large impact. The value of equivalent partial safety factors for all dead loads ranges from 1.04 to 1.10, and the upper limit value of the partial safety factor for dead load given in the current suspension bridge specifications is 1.10. When the proportion of main cable dead load is large and the proportion of bridge deck system dead load is small, the equivalent partial safety factor takes the lower limit value. Conversely, when the proportion of main cable dead load is small and the proportion of bridge deck system dead load is large, the equivalent partial safety factor takes the upper limit value. Taking a double-deck steel truss girder suspension bridge with a main span of 1860m as an example, its equivalent partial safety factor for dead load is 1.065, which can save 4.43% of the main cable wire area, compared to the partial safety factor for dead load of 1.10 given in the specification. References | Related Articles | Metrics

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Steel Bridge Rust Detection Method Based on Improved DeepLabV3+ HUANG Haixin1，HE Zhao1，CHENG Shoushan2，XU Ruining3，ZHANG Lianzhen4 2025, 44(2): 18-24.  DOI: 10.3969/j.issn.1674-0696.2025.02.03 Abstract ( )   PDF (7113KB) ( )   The rust detection algorithm is the key to the transformation of steel bridge maintenance from artificial vision to machine vision, and it is also the technical foundation for the construction of intelligent steel bridge detection robots. In order to meet the practical requirements of low energy consumption and high accuracy of rust detection algorithms for steel bridge intelligent detection robots, the DeepLabV3+ model was improved. The MobileNetV2 backbone network was used to replace the Xception backbone network in the original model, making the model lightweight and adaptable to mobile devices. The void rate in the ASPP module was optimized to improve the network's ability to extract rust of different sizes. The CBAM attention mechanism was added to enhance the model's perception and capture of key features. A comparative experiment was conducted between the improved DeepLabV3+ model and the original DeepLabV3+ model, PSPNet model, and U-Net model. At the same time, ablation experiments were conducted. Finally, the improved model was mounted on a visual robot and field engineering tests were conducted. The results show that the improved DeepLabV3+ model has an average accuracy improvement of 7.5%, an average intersection to intersection ratio improvement of 14.7%, and an average recall rate improvement of 9.1%, compared to other models in segmenting steel bridge rust images. References | Related Articles | Metrics

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Evolutionary Game Analysis of Port Carbon Reduction Path Based on Prospect Theory LIU Cuilian, LIU Na, LIANG Jing, WANG Shuang 2025, 44(2): 25-33.  DOI: 10.3969/j.issn.1674-0696.2025.02.04 Abstract ( )   PDF (1127KB) ( )   In view of the current problem of reducing the carbon emissions of port enterprises, the evolutionary game model of local governments and port enterprises was constructed by adopting the evolutionary game method modified by prospect theory. The evolutionary stability strategies of local governments and ports were comparatively studied when the central government formulated different carbon emission reduction policies, and MATLAB was used for simulation experiments. The research shows that under three kinds of carbon emission reduction policies, that is no policy formulation, carbon subsidy and carbon penalty combination, carbon subsidy and carbon trading combination, the last one is more conducive to promoting port enterprises to actively reduce carbon emissions. When the sum of the subjective perceived benefit and the perceived benefit of carbon trading obtained by the port enterprises actively reducing carbon is higher than the sum of the subjective perceived benefit and the perceived loss of carbon trading obtained by negatively reducing carbon, the port enterprises will spontaneously and actively reduce carbon emissions. Compared with increasing local governments subsidies for port enterprises, setting higher carbon trading prices will further promote port enterprises to actively reduce carbon emissions. References | Related Articles | Metrics

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Mechanical and Microscopic Properties of High-Performance Concrete Prepared by Tunneling Excavation Materials CHEN Zhongzhang1, DUAN Muzi1, CAI Shengyu1, SU Weifeng1, LI Pengfei2 2025, 44(2): 34-42.  DOI: 10.3969/j.issn.1674-0696.2025.02.05 Abstract ( )   PDF (4592KB) ( )   The feasibility of utilizing the rock from tunnel excavation materials as the coarse aggregate for high-performance concrete was investigated. The rheological properties of high-performance concrete could meet the specification requirements when the substitution rate of excavated coarse aggregate for fine aggregate was below 40%, while the 7-day and 28-day compressive strengths were decreased by 22.2% and 14.1%, respectively, and the flexural strength didnt change much. Based on the experimental results, the simple-type center of gravity design method was utilized to evaluate the mechanical and rheological properties of high-performance concrete. The stacking densities under different coarse aggregate yields were also calculated in combination with the close packing theoretical model. It is found that the needle-like grain size of the excavated coarse aggregate changes the stacking state of the material and reduces the stacking densities of the high-performance concrete, thus reducing the compressive strength of the high-performance concrete. Finally, scanning electron microscope technique was used to analyze the microstructure of excavated coarse aggregate and natural coarse aggregate high-performance concrete to verify the reason for the decrease in strength of excavated coarse aggregate high-performance concrete. References | Related Articles | Metrics

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Influence of Large Temperature Difference and Ultraviolet Radiation on the Performance of Asphalt in Cold and High-Altitude Area WANG Zhengjun1，2, GAO Renhe1, LEI Yu1，2, KE Wenhao1，2 2025, 44(2): 43-52.  DOI: 10.3969/j.issn.1674-0696.2025.02.06 Abstract ( )   PDF (1813KB) ( )   The asphalt binder was prone to ageing under cold and high altitude, which increased the cracking risk of asphalt pavement. In order to study the performance variation rule of asphalt binder under the action of large temperature difference and ultraviolet radiation, the region with large temperature difference and the region with ultraviolet radiation in Tibet were defined by taking the average daily temperature difference and the average daily total solar radiation over the years as indicators, and Tibet area was divided into 6 districts. The performance variation of asphalt binder under the coupling action of different temperature and ultraviolet radiation was studied by simulating the environment with various temperature differences and ultraviolet radiation of Tibet. The research results show that different temperature differences have little effect on the conventional physical properties, high and low temperature performance and composition changes of asphalt binder. The coupling effect of super-large temperature difference and strong ultraviolet radiation has a significant impact on the conventional physical properties of the matrix asphalt. The creep stiffness and creep rate of SBR modified asphalt have the smallest variation range, and the low-temperature crack resistance is better. The rutting factor of SBS modified asphalt has smaller increment and its high-temperature rutting resistance is better. The increment of matrix asphalt carbonyl index IC=O and sulfoxide index IS=O is 1.3 times as much as that of the modified asphalt, the colloid stability index difference was 1.4 times as much as that of the modified asphalt, and the aging degree is severe. References | Related Articles | Metrics

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DSACNet: Improved YOLOX Road Defect Detection under Foggy Conditions CHEN Lili1， JIANG Xiaohong1， ZHANG Jie2， DING Yiwen1 2025, 44(2): 53-60.  DOI: 10.3969/j.issn.1674-0696.2025.02.07 Abstract ( )   PDF (4991KB) ( )   Aiming at the problem that the quality of road image was destroyed under foggy conditions, which made the detection difficulty, an improved YOLOX detection algorithm DSACNet was proposed. YOLOX was used as the detection module in DSACNet and a reconstruction module similar to encoder-decoder was designed. By utilizing the feature reconstruction module to share the clean features generated by the reconstruction network with the detection network, the detection network could better learn the hidden features in foggy images, thereby helping DSACNet improve its detection capability under adverse weather conditions. In addition, the self_attention mechanism and self-calibration convolution were introduced to improve the feature extraction ability, and focal loss was added to solve the imbalance problem between positive and negative samples in the target detection task. The results show that the proposed DSACNet adopts an end-to-end training method, which can perform foggy image restoration and target detection at the same time and use a joint optimization strategy to combine the above two, so that the target detection network can obtain the hidden features explored by the recovery network, which is more conducive to road defect detection in foggy conditions. Compared to the original model YOLOX, the mAP of the proposed method reaches 93.5%, with an increase of 14%, and is superior to those of other mainstream target detection algorithms, which meets the accuracy requirements of road defect detection. References | Related Articles | Metrics

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Surface Treatment of Rubber Particles on the Performance of Cement Stabilized Macadam HE Zhanjun1, GUO Jin1, LIU Xiaolong1, YANG Ruochong2 2025, 44(2): 61-67.  DOI: 10.3969/j.issn.1674-0696.2025.02.08 Abstract ( )   PDF (8932KB) ( )   The disadvantages of cement stabilized macadam, such as drying shrinkage and thermal shrinkage, often cause the cracking of roads. Addition of waste tire rubber particles into cement stabilized macadam can not only achieve resource recycling but also improve the shrinkage cracking characteristics of cement stabilized macadam by utilizing the high elasticity of rubber. Due to the significant modulus difference between rubber and cement stone, the interface transition zone between the two is weak, which reduces the mechanical properties of the material. Therefore, NaOH was used for surface modification treatment of rubber. At the same time, dry shrinkage test, thermal shrinkage test and strength test were conducted to explore the influence of the modified rubber on the shrinkage cracking and mechanical performance of cement stabilized macadam. Scanning electron microscopy and energy spectrometer were used to analyze the morphology and chemical composition of interface. The results show that the thermal shrinkage and dry shrinkage of cement stabilized macadam with modified rubber powder were further reduced compared to cement stabilized macadam with untreated rubber, while the unconfined compressive strength is increased by more than 5%. The crack gap between the surface treated rubber and cement stone is significantly improved, and the value of Ca/Si in the interface transition zone is decreased. The generation of C—S—H in the interface transition zone is increased, the rubber particles are tightly wrapped by cement stone and the interface is tightly bonded. The above results indicate that the addition of surface-modified rubber powder in the cement stabilized macadam effectively improves its shrinkage cracking performance and strength characteristics. References | Related Articles | Metrics

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Performance Research on Alkali-Activated Lithium Slag Recycled Cement Stabilized Macadam Mixture Based on Grey Correlation Analysis YANG Weijun, JIN Zhenzhou, YANG Jianyu, LIU Yuhan, YAO Juntian, HE Zhihui 2025, 44(2): 68-74.  DOI: 10.3969/j.issn.1674-0696.2025.02.09 Abstract ( )   PDF (3489KB) ( )   To improve the mechanical properties and shrinkage properties of recycled base, different dosages of recycled aggregate and alkali-activated lithium slag were used to prepare alkali-activated lithium slag recycled cement stabilized macadam mixtures, and their mechanical properties, microscopic properties and shrinkage properties were investigated. The gray correlation method was further employed to investigate the correlation between the proportions of recycled aggregate and alkali-activated lithium slag and various performance parameters of the mixture. The results indicate that as the proportion of recycled aggregate increases, the mechanical properties of the recycled cement stabilized macadam mixture firstly increase and then decrease, while the drying shrinkage coefficient and temperature shrinkage coefficient gradually increase. The optimal proportions of alkali-activated lithium slag and recycled aggregate are 15% and 40%, respectively. Compared with the mixture of only 40% recycled aggregate, the alkali-activated lithium slag recycled cement stabilized macadam mixture exhibits an increase in 7-day compressive strength, splitting strength, and flexural strength by 12.9%, 8.8%, and 12.7%, respectively. Additionally, its 7-day and 28-day drying shrinkage coefficients decrease by 15.8% and 28.1%, respectively, while the average temperature shrinkage coefficient is reduced by 5.4%. The analysis of gray correlation method indicates that the correlation between the dosage of alkali-activated lithium slag and the mechanical properties and average temperature shrinkage coefficient of the mixture is higher, and the effect of recycled aggregate dosage on the drying shrinkage coefficient of the mixture is more significant. Microscopic experiments demonstrate that alkali-activated lithium slag participates in the hydration reaction, generating hydrated silicate and ettringite, which optimizes the interfacial transition zone of the mixture and makes its microstructure denser. References | Related Articles | Metrics

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Ash Content Analysis of Different Crumb Rubber Powders and Effect of Modified Asphalt WANG Wei，DUAN Danjun，ZHANG Bo，GAO Xuekai，CHANG Runtian 2025, 44(2): 75-81.  DOI: 10.3969/j.issn.1674-0696.2025.02.10 Abstract ( )   PDF (1535KB) ( )   There are many types of waste tire rubber products and crumb rubber powders prepared from them. However, there is a lack of systematic research on the quality of rubber powder from different types of waste tires and its modification effect on asphalt. Moreover, there is currently a lack of effective detection method for measuring the amount of rubber powder added in rubber asphalt. To address the above issues, the ash content of three types of rubber powder, namely nylon tires, radial tires and car tires, was first tested to explore the influence of different sampling qualities on the ash content results. Then, the composition of the ash content of three kinds of crumb rubber powders was analyzed by energy dispersivity X-ray fluorescence spectrometry (EDXRF) and X-ray diffractometer (XRD). Further, the performance improvement effects of three types of rubber powders with a dosage of 20% and 30% on asphalt were compared. The research results show that the sampling quality has a significant effect on the ash content. Overall, the ash content will increase with the increase of sampling quality, and under all four kinds of sampling qualities, there is a result of the lowest ash content in nylon tire rubber powder. There are 4 common and main constituent elements and 6 common substances in the ash content of three types of rubber powders. Overall, the material composition of the ash content of the three types of rubber powders is generally similar, but there are significant differences in their material content. For the three types of rubber powders, the increase in the dosage of crumb rubber powder results in the decrease in penetration, and increase in softening point, ductility, viscosity and elastic recovery. The nylon tire rubber powder has the best effect on improving the comprehensive performance of asphalt with a dosage of 20% and 30%. Finally, aiming at the characteristics of ash residue in crumb rubber powder and no residue in asphalt under the high-temperature ashing conditions, it is proposed that the ash content in rubber powder can be used as a marker to achieve the measurement and detection of rubber powder content in rubber asphalt. References | Related Articles | Metrics

Transportation+Big Data & Artificial Intelligence

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Traffic Safety in Mountainous Bridge and Tunnel Connection Sections under the Action of Vehicle-Road-Environment WANG Lu, HUO Lulu, ZHANG Ziyu, CHEN Hong 2025, 44(2): 82-90.  DOI: 10.3969/j.issn.1674-0696.2025.02.11 Abstract ( )   PDF (1927KB) ( )   Addressing the driving safety risks in bridge-tunnel transition sections of mountain highways under strong crosswinds, an analysis is conducted based on a multi-dimensional coupled mechanical model of vehicle-road-environment. Utilizing the CarSim simulation platform, 240 scenarios were constructed, encompassing four typical vehicle speeds, three bridge lengths, five wind speed gradients, and complex environmental conditions such as ice and snow with low adhesion. The focus is on analyzing the impact of parameters such as wind speed, vehicle speed (60, 80, 100, 120 km/h), bridge length (20, 65, 100 m), road adhesion coefficient, superelevation (0.06), and circular curve radius on vehicle driving safety and lateral stability. Corrective methods are proposed for unstable conditions. The research results indicate that vehicle driving stability is negatively correlated with wind speed and positively correlated with superelevation. When encountering a wind speed of level 5, a bridge length of 100 m, a superelevation of 0.06, and icy conditions, the circular curve radius needs to be increased to 134, 270, and 466 m, respectively, to counteract the lateral wind load and ensure safe and stable vehicle operation. References | Related Articles | Metrics

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Non-linear Effect of Built Environment on Elderly's Walking Time Considering the Heterogeneity of Travel Purposes ZHU Zhenjun1, HAN Ji1, TANG Chao2, GUO Xiucheng3, JIAO Zhenyu1, ZHANG Ruijia1 2025, 44(2): 91-98.  DOI: 10.3969/j.issn.1674-0696.2025.02.12 Abstract ( )   PDF (1218KB) ( )   In order to study the influence of built environment on the walking time of the elderly considering different travel purposes, the extreme gradient boosting tree model (XGBoost) was constructed by using Shantou resident travel survey data in 2021, to analyze the non-linear relationship between the built environment and the walking time of the elderly. Combined with SHAP algorithm, the relative importance of variables and overall interpretability was output. The research results show that the goodness of fit of the model is higher after classifying travel purposes. The importance of the number of household bicycles increases significantly for survival travel, while the importance of the number of cars decreases. The importance of normalized difference vegetation index (NDVI) is highest for living travel, while the importance of all other built environment variables increases. The number of bus stops and land use mixing degree have a “V”-shaped relationship with walking time of the elderly, with the effective influence range of 5~13 and 0.40~0.80 respectively, and both the number of bus stops above 10 and land use mixing degree above 0.70 can promote walking time of the elderly. The number of intersections has a significant positive impact on NDVI overall, but NDVI exhibits a threshold effect, with a corresponding threshold value of 0.33. The research results can provide a theoretical basis for improving the aging-friendly environment of community construction and formulating transportation policies for the elderly. References | Related Articles | Metrics

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Dynamic Induction Method for Different Vehicle Types in Urban Extra-long Tunnel LIU Wei, BAO Yuning, RAO Chang, LI Jiangrong 2025, 44(2): 99-107.  DOI: 10.3969/j.issn.1674-0696.2025.02.13 Abstract ( )   PDF (2878KB) ( )   In order to realize the collaborative improvement of traffic safety and efficiency in urban extra-long tunnels, a dynamic guidance model for urban extra-long tunnel lanes considering differences in vehicle types was proposed. Firstly, based on the spatial distribution characteristics of tunnel accidents, the urban extra-long tunnel was subdivided into multiple sections, and the guidance area for vehicle lane changing was clearly defined. Then, based on the principle of cellular automata, a lane-change model and a speed induction model based on NS model optimization were constructed by taking a one-way three-lane tunnel as the research object, to guide the lane selection and speed adjustment of vehicles under different traffic flow conditions. Finally, Chongqing Shuangbei Tunnel was selected as the empirical object, COM interface of VISSIM software was used for secondary development, and the simulation platform was constructed to compare and analyze the indicators before and after the guidance, such as traffic collision rate, standard deviation of speed, average travel time and average speed. The results show that after the implementation of lane dynamic guidance, the traffic conflict rate is significantly reduced by 20.9%, the maximum standard deviation of vehicle speed is reduced by 3.24km/h, the average travel time is shortened by 3.7%~16.1%, and the average vehicle speed is increased by 5.1%~14.5%. Especially in the case of high-density traffic flow, the dynamic guidance strategy shows a more significant optimization effect, and the improvement of small vehicles is more prominent, which confirms the practicability and effectiveness of the proposed method. References | Related Articles | Metrics

Transportation Equipment

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Investigation of Radial Electromagnetic Force and Torque Fluctuations of SRM under Air Gap Eccentricity ZHENG Mengdong1，HOU Mengmeng2，LUO Xiaoliang2，DENG Zhaoxue2，QIN Hansheng2 2025, 44(2): 108-117.  DOI: 10.3969/j.issn.1674-0696.2025.02.14 Abstract ( )   PDF (3425KB) ( )   In response to the problem of air gap eccentricity caused by external disturbances such as road excitation and emergency braking during the operation of electric vehicles, which affeced the normal operation of the wheel switched reluctance motor (SRM), the radial magnetic force at different obtained on the stator surface of SRM was firstly determined on the basis of Maxwell stress tensor method. The variation characteristics of radial electromagnetic force and electromagnetic torque under different air gap eccentricity and different angles were analyzed, and the influence rule of air gap eccentricity on the above two was revealed under transient conditions. It was clarified that air gap eccentricity not only increased radial electromagnetic force but also significantly amplified motor torque fluctuations. Secondly, by analyzing the distribution of magnetic flux density in the stator and rotor, it was clear that the width of the stator and rotor salient poles was the main factor affecting radial electromagnetic force and electromagnetic torque. Lastly, the fluctuations of radial electromagnetic force and electromagnetic torque were suppressed through multi-objective optimization of structural parameters, which were reduced by 15.4% and 24.9% respectively. The optimization scheme was improved under different air gap eccentricities. References | Related Articles | Metrics

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Structural Design and Simulation Analysis of Cooling Systems for On-Board Lithium-ion Power Battery Pack SHEN Jiangwei, YU Shuai, LI Xijin, CHEN Zheng, XIA Xuelei 2025, 44(2): 118-126.  DOI: 10.3969/j.issn.1674-0696.2025.02.15 Abstract ( )   PDF (7559KB) ( )   Aiming at the problems of insufficient heat dissipation and high system energy consumption of lithium-ion battery packs, the effects of different semi-circular arc liquid cooling plate structures on the heat dissipation performance of battery packs and the pressure drop in the fluid domain were analyzed by Fluent software. Based on the results of three key indicators of the battery pack, that is, the maximum temperature, the maximum temperature difference and pressure drop, 8 sets of cooling structures were designed, and the structure 2 was selected to further investigate the effects of coolant inlet flow rate, inlet temperature, and liquid cooling plate height on the heat dissipation efficiency of the battery pack. The research results show that the bidirectional flow structure is more beneficial for improving the temperature uniformity of the battery pack compared to the traditional single flow structure. Adjusting the inlet and outlet positions of the coolant will change the flow distribution of the coolant, thereby affecting the heat dissipation performance of the battery pack. Increasing the coolant flow rate can reduce the maximum temperature and temperature difference of the battery pack, but when the flow rate exceeds 0.3 m/s, the improvement in heat dissipation effect will become limited and the system energy consumption will increase. Lowering the coolant temperature can effectively reduce the maximum temperature of the battery pack, but it will increase the temperature difference of the battery pack. Increasing the liquid cooling plate height helps to enhance the heat dissipation effect of the battery pack and improve temperature uniformity. When the coolant flow rate is 0.3 m/s, the coolant inlet temperature is not lower than 25 ℃, and the height of the liquid cooling plate is not less than 55mm, the maximum temperature of the battery pack after cooling with structure 2 is 30.61 ℃, and the maximum temperature difference can be controlled within 5 ℃, which has a better temperature uniformity. References | Related Articles | Metrics