Vibration Serviceability Analysis Of Large-scale Integrated Building-bridge Structures Induced By Running Trains

Compared with traditional railway station buildings,integrated building–bridge structures high-speed railway station can realize "zero transfer" and three-dimensional traffic flow.However,because the train track is located in the elevated floor,where directly subjected to train–track dynamic forces that result in excessive vibrations.In this context,the train-induced vibration of integrated building–bridge structures is deeply studied in this paper.This paper takes Kunming South railway station as the engineering background.The vehicle-track model and integrated building–bridge structures finite element model in frequency domain are established,and the vibration response results of integrated building–bridge structures are obtained.The rationality of the modeling method is verified by comparing the simulation results with the measured data.According to the vibration response of integrated building–bridge structures,a total of 7 conditions were set up to analyze the train-induced vibration response of integrated building–bridge structures under the excitation of different running tracks and speeds of high-speed trains.The effects of track parameters and station building structural parameters on force transfer characteristics,station vibration and driving safety are further analyzed.The main conclusions are as follows:(1)When the train passes through track #1 at 120 km/h,the frequency spectrum characteristics of the investigated points close to the loading position are similar.With the increase of the distance from the loading position,the dominant frequency range of the investigated points near the E-axis of the rail-bearing layer decreases gradually.The dominant frequency range of the investigated points near the E-axis of the rail-bearing layer is 31.5-125 Hz,and the dominant frequency of the investigated points near the E-axis of the waiting layer is 40-100 Hz.(2)Comparing the response of the station when the train is running on different tracks: the frequency spectrum of each investigated point on the station is not sensitive to the loading track;when the two tracks are running at the same time,the vibration level of each investigated point will increase because of the superposition of vibration energy.(3)With the increase of driving speed,the components of vibration frequencies of station buildings increase at the same rate,and the overall vibration level increases by 7.8 dB with the increase of driving speed of 100 km/h.For stations without any vibration reduction measures,the vibration of the stations can be effectively controlled within the limit by limiting the train speed at 40 km/h.(4)Track vibration reduction measures will change the natural frequency of ballasted track system,and then force transfer rate and vibration of track components will change in different frequency ranges.Four kinds of track vibration reduction measures have a certain effect on the vibration of station buildings.Among them,ballast cushion has the best effect(about 6 dB),and has no obvious negative effect on traffic safety;other measures can reduce the vibration of rail bearing layer and waiting layer by about 2 dB,among which elastic fasteners can significantly increase rail displacement;therefore,ballast cushion has the best comprehensive effect of vibration reduction.(5)Three vibration reduction measures are considered from the structural parameters of the station building: they have little effect on the dynamic characteristics of the train and track subsystems;among them,increasing the cross-section size of the column can significantly reduce the vibration response of the waiting floor(about 3-5 dB),and increasing the floor thickness of the station building structure is ineffective for the vibration control of the station building structure..