Dynamic Characteristics Calculation Method Of Simply Supported Bridge With Variable Sections

Simply supported bridge has lots of advantages, such as the clear stress characteristics and simple construction technology, in addition, under the influence of the foundation displacement and other factors, the girder does not generate additional internal force, so simply supported bridge has been widely used in the bridge engineering field. Sometimes in order to make the section stress more reasonable and save the engineering cost or obtain a large bridge clearance under the pier height, there will often be variable cross sections in the simply supported bridge. The dynamic characteristics of bridge structure is an important parameter in the design and evaluation of bridge structure. In view of the wide application and the importance of dynamic characteristics of the simply supported bridge with variable sections in bridge engineering field, it is very necessary to study the dynamic characteristics of the simply supported bridge with variable sections.In order to form an effective and reliable dynamic characteristics calculation method of simply supported bridge with variable sections, this paper, based on the project of the bridge of Gongping in Changchun, carried out the research on dynamic characteristics calculation method of simply supported bridge with variable sections, the main research work are as follows:1. The partial differential equation of the vibration of the simply supported beam with variable sections is derived. Based on this equation, the element stiffness matrix and mass matrix of the simply supported beam with variable sections are presented by using the Galerkin weighted residual method.2. Firstly, the general solution of the vibration function of beam with variable sections is derived in the case that the bending moment of inertia and mass per unit length is in accordance with some specific distributions. Then, based on the basic principle of the transfer matrix method, the calculation method of dynamic characteristics of the simply supported beam with variable sections is formed.3. In order to verify the validity and reliability of this method, this paper applied the method to the actual project of the bridge of Gongping in Changchun.