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Wang H.,Nanjing Southeast University | Liu Z.,Liaoning Provincial Communication Planning and Design Institute | Zhang Z.,Tianjing Municipal Engineering Design and Research Institute | Li Y.,Nanjing Southeast University | Wang W.,Nanjing Southeast University
Dongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Southeast University (Natural Science Edition)

Due to the fact that the traditional car-following and lane-changing combined models fail to take the driver's anticipation into consideration, based on full velocity difference car-following model and probabilistic lane-changing model, a double-head car-following and lane-changing combined model was proposed, and the method of model calibration was presented as well. The traffic data of Emeryville section in American freeway I 80 from next generation simulation (NGSIM) open data source were used to calibrate the proposed model. The trajectory-based method and maximal likelihood method were carried out to calibrate car-following model and lane-changing model, respectively. Numerical simulation according to the real freeway traffic scenario in NGSIM was designed. The results indicate that both the average speed and the speed dispersion in the simulation have the errors around 5.0%, and the errors for both the times and rate of lane changes are less than 20.0%. Therefore, the proposed model can describe the microscopic characteristics of traffic flow appropriately and simulate the real freeway traffic dynamics successfully. ©, 2015, Southeast University. All right reserved. Source

Liu X.,Harbin Institute of Technology | Feng D.,Harbin Institute of Technology | Tang H.,Liaoning Provincial Communication Planning and Design Institute | Zhou C.,Harbin Institute of Technology | Li J.,Harbin Institute of Technology
Journal of Testing and Evaluation

Bridge deck pavement layers are prone to bending fatigue and shear failure because of the continuous vibration, the vertical instant impact, and horizontal dynamic shear effect from vehicles onto the pavement system. To ensure the durability of pavement systems, a typical pavement system on a steel bridge was studied through numerical simulation and laboratory tests. The maximum tensile stress at the bottom layer and the maximum interlayer shear stress of bridge deck pavement were obtained under different loading conditions in numerical simulations. Then direct shear tests were conducted to study the fatigue characteristics of bridge deck pavement materials and structure. Finally, the fatigue resistance of the asphalt pavement system was investigated under the typical traffic level in the northeast of China. This study is helpful to design steel bridge deck pavement systems with good bending fatigue and shear resistance. © 2016 ASTM Int'l (all rights reserved). Source

Li M.,Northeastern University China | Zhu F.-S.,Northeastern University China | Zhao Y.-P.,Liaoning Provincial Communication Planning and Design Institute
Zhongguo Gonglu Xuebao/China Journal of Highway and Transport

Theoretical analysis of CFRP reinforced concrete bridge fatigue crack propagation rate was conducted on the basis of linear progressive superimposed assumption. On the basis of crack propagation model expression and the analysis of the relationship between the three point bending beam stress intensity factor and the equivalent crack length, the crack growth rate was calculated to estimate the fatigue life of CFRP reinforced bridge. At the same time, experiment study was made on the fatigue crack propagation of the CFRP reinforced bridge, and the strain accumulation of the reinforced beams by single and double CFRP layer along the CFRP direction was analyzed to expound the growth rate and propagation behavior of the reinforced beam crack under load. The results show that CFRP plays an important role in the anti-fatigue for reinforced beam under fatigue load. The fatigue life estimation theory is proved to have smaller error which meets the actual demand of the CFRP reinforced concrete bridge through comparing theoretical calculation results with the test results. ©, 2014, Xi'an Highway University. All right reserved. Source

Wang L.-F.,Northeast Forestry University | Wang E.-Q.,Northeast Forestry University | Sun Y.-C.,Liaoning Provincial Communication Planning and Design Institute | He D.-P.,Northeast Forestry University | Ge J.-Y.,Shijiazhuang University
Jiaotong Yunshu Gongcheng Xuebao/Journal of Traffic and Transportation Engineering

In order to reveal the mechanical properties of each component of cable-stayed bridge in rotation construction process, the 3D numerical simulation model of the first domestic single-point flat-hinge cable-stayed bridge of China was built, and was verified by using the measured data. The angular acceleration of cable-stayed bridge in rotation construction process was deduced according to the theory of rigid body rotation around a fixed axle. In view of two typical construction stages of accelerating rotation and uniform rotation, the stress states of main girder, tower, pier, bracket, shaft and dial were researched. In the rotation process of cable-stayed bridge, the influence laws of angular velocity and angular acceleration on bridge stress were revealed, and the reasonable construction angular velocity and angular acceleration were calculated. Calculation result indicates that in the process of uniform rotation, the normal stress change of control section is approximately direct proportional to the square of angular velocity. When the measured angular velocity is 0.01 rad·min-1, the maximum stress changing value of control section is only -2.00 Pa. In the process of accelerating rotation, the stress of main girder cross section presents skew symmetric distribution along the center line of main girder, and when the measured angular acceleration is 6.5×10-3 rad·s-2, the stress changing value of tower root solid section at lower edge is -3.33 MPa, and the stress changes significantly. In the process of accelerating rotation, start from the bracket bottom, the torque of each pier cross section along the height direction decreases. So in the process of uniform rotation, the influence of angular velocity on the stress of main girder section may be ignored. In the process of accelerating rotation, in order to ensure the construction safety and shorten the rotation time, the rotation angular acceleration of cable-stayed bridge should be limited. ©, 2015, Chang'an University. All right reserved. Source

Jun L.,Northeastern University China | Zhang G.H.,Liaoning Provincial Communication Planning and Design Institute
Applied Mechanics and Materials

ABAQUS finite element analysis software and load - structure method are adapted in this paper and the structure is simplified as a two-dimensional plane model. 25 kinds of working condition including five hole sizes: 0.6m, 1.2m, 1.5m, 1.8m, 2.1m and five hole positions varying from vault to arch springing are studied and the safety factor distribution of lining are obtained. By comparing the safety factor at dangerous section in lining with hole to that in no damage lining, a convenient evaluation method about the effect of hole to lining safety is proposed. © (2014) Trans Tech Publications, Switzerland. Source

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