Vibration Serviceability Of Large-span Cantilevered Structures Induced By Train And Pedestrian Load

With the arrival of the21st century, railway transport speed, capacity and volume are rising constantly. The train-bridge station large span structures have been widely used for its unique and novel structure forms and reasonable function zoning. The train-bridge large span station structures are in the complex situations for force because of elevated railway bridge as the foundation of the structure. The running trains will generate vibration excitation to the elevated bridges during structures at use. The vibration excitation spreads to the upper structural floors via elevated bridges and their piers and vertical support elements, causing upper structures generate vibration and leading to the discomfort of the passengers inside the station. The station structure also as an important hub for concentrated passengers, large flow of people and crowd density with complex human behavior activities will appear. Because of large-span, low frequency and damping for upper structure floors, the floors will generate significant vibration under the pedestrian load, causing the passengers discomfort and panic along with the degradation of structure performance. In the train-bridge station structures, the vibration serviceability problems will cause more concern for some regions designed for large-span cantilevered structures. Therefore, this paper takes Nanchang West Station which is a typical train-bridge station as the engineering background, researching on the vibration serviceability problems of large-span cantilevered structures of commercial mezzanine induced by train and pedestrian load. The specific research work are as follows:1. Integrating analysize domestic and foreign all various vibration serviceability norms and standards. The standards which evaluate the evaluate the vibration serviceability of Nanchang West Station Large-span cantilevered structure induced by train and pedestrian load are determined ultimately combined with the actual characteristics of the project.2. In connection with train-bridge station large span structures, according to the relationship between vehicle and track, vehicle-track calculation model is established. The sleeper force time-history is obtained by fourth-order Runge-Kutta method. A sub-structure of Nanchang West Station is selected to establish its finite element model. The structural dynamic response of the large-span cantilevered structure of the commercial mezzanine of the sub-structure of Nanchang West station is obtained by taking sleeper force time-history as its input load. The vibration serviceability standard is utilized to evaluate its vibration serviceability induced by train load.3.The14.5mx17.5m large-span cantilevered structure of the commercial mezzanine of the sub-structure of Nanchang West Station model is established. According to the pedestrian load defined by vibration serviceability combined with Wuhan Railway Station crowd density in situ measurement test results conducted by our team, the dynamic response of large-span cantilevered structure is calculated and then evaluate its vibration serviceability induced by pedestrian load.Finally, recommendations and prospect are proposed on the basis of summary of the research work by this paper.