Wang Z.-C.,Hefei University of Technology |
Huang C.-Y.,Hefei University of Technology |
He Z.-C.,Shanghai Railway Bureau |
Wang Y.-P.,Ningan Railway Company of Shanghai Railway Bureau
Advances in Structural Engineering | Year: 2017
Strain modes of structures reflect the distribution rule of dynamic strain and can be of service to structural health monitoring. This article presents a new method to estimate the strain modes of beam structures based on the measured dynamic strain. Since the cross-correlation matrix of the modal coordinates is a diagonal matrix, thus, the cross-correlation matrix of the measured dynamic strain is also a diagonal matrix, and the strain modes can be obtained to find the eigenvectors of the strain cross-correlation matrix. The strain modes of a simply support beam and a continuous beam subjected to various impulsive excitations are identified from the numerical simulations using the proposed method. The noise effect is also investigated in this article. The numerical results show that the proposed method can effectively identify the strain modes even with noise effect. Finally, the method is verified through the experiment of a simply supported beam under hammering excitation. The test results also show that the proposed method can estimate the strain modes of beam structures with a high accuracy. © The Author(s) 2016.
Zhang Y.-B.,Shijiazhuang University |
Song J.-J.,Shanghai Railway Bureau |
Chen W.,Shijiazhuang University
Journal of Railway Engineering Society | Year: 2015
Research purposes: When continuous beam of high-speed railway is completed, with the passage of time, because of the influence of shrinkage and creep, continuous beam deflection will keep changing. The long-term deflection of the bridge will be affected in different degrees by relative humidity, loading age, shrinkage and creep coefficient. In order to study the influence of the creep and shrinkage of concrete on deformation and internal force of long span bridges, this paper chooses approach practical analysis pattern of creep and shrinkage, reasonably conducts analysis of creep and shrinkage effect, it is very necessary to properly think over the influence of shrinkage and creep. Research conclusions: (1) The relative humidity reducing, the long-term deflection increasing, are disadvantageous to ensure the bridge line, so increasing the relative humidity, such as the use of steam curing measures has a decreasing effect for the length of deflection of the bridge, is beneficial to keep the bridge line of the bridge. (2) The short loading age of the bridge will also increase long-term deflection, so in the construction process, limiting construction load early in the new pouring of beam section, can reduce the long-term deflection. (3) Creep coefficient has a great effect on the long-term deflection of the bridge, creep coefficient increases, the long-term deflection of the bridge increases, selecting the appropriate creep coefficient is pretty important for predicting the length of the deflection of the bridge, so it is necessary to determine the creep coefficient by taking the test measures in the design of important bridge. (4) This research conclusion has a guiding significance for the construction and pre-camber calculation for the high-speed railway continuous beam. ©, 2015, Editorial Department of Journal of Railway Engineering Society. All right reserved.
Wang F.,Shanghai Railway Bureau |
Jin W.,Shanghai Railway Bureau |
Wang H.-K.,Shanghai Railway Bureau |
Tao Y.-P.,Shanghai Railway Bureau |
Xu Y.-F.,Shanghai JiaoTong University
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2010
Lateral displacement is one of the reasons for foundation settlement, and the results of finite element analysis establish a good correlation between the lateral displacement and settlement. For foundations of different embankment height and different void ratios, it gives the settlement correction coefficients which are caused by lateral displacement. Practical engineering instance shows that the correction coefficients from finite element analysis have good applicability and prediction accuracy.
Tao H.,Southwest Jiaotong University |
Hu H.,Southwest Jiaotong University |
Jiang X.,Southwest Jiaotong University |
He Z.,Southwest Jiaotong University |
Zhao C.,Shanghai Railway Bureau
Dianwang Jishu/Power System Technology | Year: 2016
Recently, low frequency voltage oscillation and fluctuation appeared in a number of electrified railways, leading to train traction blockade. Low frequency voltage oscillation in integrated train-catenary system has strong unpredictability. In this paper, low frequency voltage oscillation was analyzed with impedance-based method. Integrated simulation model of HXD2B electric train and traction network was built on Matlab/Simulink, and low frequency voltage oscillation in traction power supply system was reproduced. In comparison with measured waveforms, accuracy of the proposed model was verified. On this basis, different factors affecting low frequency voltage oscillation (e.g. catenary length, connection mode of traction transformer, traction load and control parameters of train) were analyzed and discussed. Simulation results showed that both reducing traction power supply system impedance (including catenary length, connection mode of traction transformer) and increasing traction system impedance (including traction load and control parameters of train) can suppress low frequency voltage oscillation. © 2016, Power System Technology Press. All right reserved.
Hong L.,Tongji University |
Qu S.Y.,Shanghai Railway Bureau
Advanced Materials Research | Year: 2013
As there are uncertainties in the public transportation network optimization evaluation process, many existing methods cannot simultaneously describe the uncertainties in different types and therefore will result in an un-objective reflection of the actual problem. In this paper set-pair and entropy analysis is used to analyze the internal connections of the system globally and locally. This model which is simple in calculation and easy to use has theoretical and practical values for new ideas and methods of uncertainty analysis of the public transportation network optimization. © (2013) Trans Tech Publications, Switzerland.
Wang F.,Shanghai Railway Bureau
Beijing Jiaotong Daxue Xuebao/Journal of Beijing Jiaotong University | Year: 2012
A vibration test in Xinmeng river section has been conducted to analyze the vibration characteristics of Hu-Ning high-speed railway and its effect on the adjacent existing railway. The transmission characteristics of vibrations between the two lines are analyzed from vibration acceleration time history, peak acceleration, peak velocity and 1/3 octave spectrum of acceleration. When the train runs through the subgrade of existing railway or viaduct of Hu-Ning high-speed railway, the vertical vibration is much bigger than lateral vibration. While trains with different locomotive types run through the existing line, the vibration in subgrade stucture will be different, but nearly the same in the long distance. Fastener system and bearing are the key factors for vibration attenuation. According to the relative standards of China and abroad, the vibration produced by the high-speed railway almost has no effects on the structures of adjacent existing railway, and the dominant frequency of Hu-Ning high-speed railway is in the band of 31.5 Hz and 63 Hz, but the vibration dominant frequency of the existing lines will be different according to locomotive types.
Li J.,Shanghai Railway Bureau
Journal of Railway Engineering Society | Year: 2014
Research purposes: When there was new construction project near the existing railway, the excavation activities often affected the slope stability. Even worse, the landslide would be caused as a result of the construction project and associated accidents occurred frequently. So it is essentially important to evaluate the slope stability properly in order to ensure the safe operation of existing railway. In this paper, a new reliability slope stability method was established based on the finite element strength reduction method and the point estimate method, and it was applied to an actual project. Research conclusions: (1)Slope stability evaluation method based on reliability theory, can comprehensively reflect the influence of the geotechnical parameters of spatial discreteness and time variability, the analysis result more accord with the engineering practice. (2) The reliability slope stability method established in this paper can overcome the shortcomings of traditional safety factor method and can show a better interpretation for the slope stability analysis with the variation of geotechnique parameter. (3) By using the new reliability slope stability method established in this paper, the analysis process is simple and the calculation results is consistent with the Monte-Carlo method, so it is reliable method and has a good promotional value. It can provide a good reference for the similar engineering.
Guo Z.,Shanghai Railway Bureau
Beijing Jiaotong Daxue Xuebao/Journal of Beijing Jiaotong University | Year: 2015
Beijing-Shanghai high speed railway is the longest high speed railway in the world built under the highest standard. The passenger flow was more than 100 million in 2014. The continuous increase of passengers has approached its maximum transportation capacity. After a thorough analysis of the weak links which compromise the transportation capacity of Beijing-Shanghai high speed railway, a preliminary proposal of technology, expansion and reconstruction is put forward from the angle of system engineering to enlarge transportation capacity so as to ensure that the high speed railway can accommodate even larger passenger flow. ©, 2015, Journal Northern Jiaotong University. All right reserved.
Li Q.,Beijing Jiaotong University |
Liu R.,Beijing Jiaotong University |
Zhang J.,Shanghai Railway Bureau |
Sun Q.,Beijing Jiaotong University
Procedia Engineering | Year: 2014
Information technology has significant potential to enhance the engineering quality of the risk management of railway construction projects. The Shanghai Railway Bureau has promoted a risk management method based on the "A Figure and Four Tables" method (AFFTM) to assess the engineering quality; however, this method still suffers from several problems in railway construction project management. In this paper, we have combined the concepts and processes of the AFFTM with those of information technology and presented the implementation scheme of a new risk management system-the railway construction project quality risk management information system (RCPQRMIS)-that can be used to design and develop workable information tools for quality risk management. The paper analyzes the data standards of RCPQRMIS and creates a model for dynamically tracking the quality risk ("quality risk dynamic tracking" model) for providing pre-warning information on quality risk ("quality risk pre-warning" model) and for automatically generating publicity parameters for quality risk ("automatically generated quality risk publicity figure" model). The proposed system enables the visualization of the quality associated with the risk control, dynamic tracking, automatic pre-warning, and closed-loop management of railway construction projects. In addition, this paper presents the functional modules of the RCPQRMIS and its practical applications. Our application results show that the system successfully realized unified management of risk source information and multi-level sharing. In this manner, by using our system, we were able to significantly improve real-time tracking and pre-warning of the risk state, automatic generation of quality risk publicity figures, efficiency, and risk management levels. © 2014 The Authors. Published by Elsevier Ltd.
Zheng Q.J.,Beijing Jiaotong University |
Han B.M.,Beijing Jiaotong University |
Li H.,Shanghai Railway Bureau
Applied Mechanics and Materials | Year: 2014
Based on the relationship between passenger flow and demand of electric multiple units (EMU), a new methodology to calculate the EMU demand and allocate the EMU is proposed, which can meet the demand of passenger as well as avoid the waste of transport capacity. An offline allocation plan of EMU is designed by analyzing the fluctuation in passenger flow, passenger average haul distance, passenger load factor and so on. Using the methodology, the EMU allocation problem is solved through program, which is used in Beijing-Shanghai High-speed Railway to obtain the EMU allocation plan. © (2014) Trans Tech Publications, Switzerland.