Urban Elevated Bridges Vehicle - Bridge Coupled Time-varying System Dynamic Response Analysis

Urban viaduct, because of its excellent transport capacity and high efficiency, plays a very important role in the urban transport organization system. Meanwhile,because of its beautiful shape and amazing style, urban viaduct often becomes to be wonderful scenery of a city. But, we should recognize that heavy load and high passing-density of vehicles always cause a problem, the vehicle-bridge coupled dynamic response which can not to be ignored. To study the nature law of this response is neccessary. Based on the time-variant vehicle-bridge coupled dynamic response analysis of a viaduct in the Xiaoxiang Road, the major completed works of this paper are shown as follows:1. The development of urban viaduct at home and abroad were introduced. The research history and current situation of the time-variant vehicle-bridge coupled system were reviewed. The main research directions of vehicle-bridge coupled dynamic response of urban viaduct were summed up.2. This paper introduces the finite element method for the bridge structure model simulation and the specific analysis method of the deck imperfection simulation. The vehicle model used in dynamic response analysis is proposed, and the basic assumptions and displacement mode of the vehicle model are explained in this paper. The motion equations of time-variant vehicle-bridge coupled system are established under the stationary value principle of the total dynamic potential energy in elastic system and "sit in the right seaf" principle.3. This paper expoundes the main structure and the function module compiling ideas of the program VBS-2. The project survey of the viaduct is introduced. The vibration characteristics of the viaduct are calculated with software, and the top ten natural frequencies and modes of full bridge have been analyzed.4. This paper briefly introduces the content and methods of a dynamic test on the viaduct in the Xiaoxiang Road. The bridge model and the vehicle parameters for analyzing by VBS-2 are described. The test data and the result calculated by VBS-2 are compared and analyzed.5. Using VBS-2, the interaction relationship between the vehicle parameters, the imperfection of deck and the vehicle-bridge coupled dynamic response of the viaduct is researched. The conclusions in this paper would make reference for daily operation and management to viaducts in the Xiaoxiang Road.