H. Xia

Experimental analysis of a high-speed railway bridge under Thalys trains

Abstract In this paper dynamic experiments on the Antoing Bridge located on the high-speed railway line between Paris and Brussels are reported. The experiments were co-operatively carried out by the Northern Jiaotong University from China, the Catholic University of Leuven, the Free University of Brussels and the Belgium Railway Company NMBS-SNCB from Belgium. The bridge is composed of multi-span simply supported PC girders with spans of 50xa0m and U-shaped sections. The loads are the high-speed Thalys trains with articulated vehicles. The speeds of the Thalys trains were between 265 and 310xa0km/h. In the experiments, the dynamic responses of the bridge such as the deflections, the accelerations and the strains that were measured by a laser velocity displacement transducer accelerometers and strain gauges, respectively. Many useful results have been obtained from the analysis of the recorded data. The tests and the measured results can be a reference for the study and the design of high-speed railway bridges.

A VEHICLE–BRIDGE LINEAR INTERACTION MODEL AND ITS VALIDATION

A linear wheel–rail interaction model for the vehicle–bridge coupling system is presented in this paper. The vehicle subsystem is modeled by the rigid-body dynamics method, the bridge subsystem by both the direct stiffness method and superposition method, and the wheel–rail interaction by the corresponding assumption and simplified Kalker creep theory. Based on the above modeling for the wheel–rail interaction system, linear simultaneous equations are established and solved. As a case study, the response of the Pioneer train traversing a 24 m simply–supported girder bridge is calculated. The proposed analysis procedure is validated through comparison of the calculated results with the measured ones. Also, some vibration characteristics of the system are discussed.

Dynamic analysis of train-bridge system and its application in steel girder reinforcement

Abstract In this paper, a spatial dynamic analysis model for the train–bridge system under random excitations was established. The random excitations were analyzed and generated by the time series autoregressive model from the experimentally measured wheel accelerations. The whole histories of the train running on the bridges were simulated on computer. The responses of bridges were calculated and statistically studied. Based on the calculation results, the reinforcement schemes for steel girders were designed and some of them were applied to real bridges. The field-tests were carried out before and after the bridge reinforcement. The measured data from the tests proved the effectiveness of the reinforcement schemes.

Vibration Resonance and Cancellation of Simply Supported Bridges under Moving Train Loads

Based on the theoretical solution for vibrations of simply supported bridges under moving train loads, resonance and cancellation conditions are derived. The results reveal two types of vibration cancellations for simply supported bridges under moving train loads: the first is related to a single moving load, which is independent of the number and the composition of the train, while the second is related to the interval between a pair of moving loads. When cancellation occurs, the free vibrations induced by the moving loads cancel to null, and the bridge response is determined by the loads still on it. A resonance disappearance effect occurs when train speed meets both the resonance and cancellation conditions, while the cancellation plays a predominant role. Bridge damping has an influence on the cancellation effect: the higher the damping and the longer the interval between the loads, the lower is the cancellation efficiency. In a case study, dynamic responses of a bridge under high-speed train loads are analyzed and the mechanisms of resonance and cancellation are explained to support the theoretical solution.

A COMPARISON OF DIFFERENT SOLUTION ALGORITHMS FOR THE NUMERICAL ANALYSIS OF VEHICLE-BRIDGE INTERACTION

The interaction between a bridge and a train moving on the bridge is a coupled dynamic problem. The equations of motion of the bridge and the vehicle are coupled by the time dependent contact forces. At each time step, the motion of the bridge influences the forces transferred to the vehicle and this, in turn, changes the forces acting on the bridge. In this paper, a comparison of three different time domain solution algorithms for the coupled equation of motion of the train–bridge system is presented. Guidelines are given for a good choice of the time step.

Dynamic responses of Tsing Ma Bridge and running safety of trains subjected to Typhoon York

A three-dimensional wind–train–bridge interaction model, which consists of a spatial finite element bridge model, a train model composed of eight 4-axle identical coaches of 27 degrees of freedom, and a turbulent wind model is established for the Tsing Ma suspension bridge located in Hong Kong during Typhoon York. The acceleration and displacement responses of the bridge induced by turbulent winds and running trains are computed and compared with the responses measured from the field. The comparison is found to be satisfactory in general. The runnability of the train passing through the Tsing Ma Bridge at different speeds is researched under turbulent winds. Then the threshold curve of wind velocity for ensuring the running safety of the train in the bridge deck is proposed, from which the allowable train speed at different wind velocities can be determined.

Application of Train-Bridge-Interaction Analysis to Bridge Design of High-Speed Railways in China

During the design of high-speed railway bridges in China, the dynamic responses of bridges under high-speed trains and the running properties of train vehicles were systematically studied by the Academy of Railway Sciences and some universities under the organization of the Ministry of Railways of China. In this paper, some practical applications of train-bridge interaction study in the high-speed railway bridge design in China are introduced, through the research work by the Beijing Jiaotong University. The analytical model of train-bridge interaction system is established, by which the dynamic responses of the bridge under the actions of high-speed trains, wind and earthquake excitations, as well as the running safety and stability indices of train vehicles are analyzed. Many useful results have been applied, through providing important parameters and references, to the practical bridge designs in the special passenger railways and high-speed railways in China.