Study For Design Theories Of Single Pylon Cable-stayed Bridges

Mainlined by the design theories of single pylon cable-stayed bridges, several interrelated problems are amply studied in this dissertation as follows:(1) The existing research results and practices of single pylon cable-stayed bridges were summarized at first, and the problems, which should be studied further, are then brought forward. There are a little research on single pylon cable-stayed bridges. The traditionary research is mostly on double pylon cable-stayed bridges.The connotations of design theories is very rich, it contains research of the system of bridges, parameters, characteristic components, conceptual design and the optimization of the design parameters.(2) The conception the "system" is proposed, then basically, the system of single pylon cable-stayed bridges is classified systemically. The special mechanical behaviors of all kinds of single pylon cable-stayed systems under various loads, are systemically studied.Based on the existing research results and practices, some structure models of existing bridges, which are single pylon cable-stayed bridges, are considered, and their displacement, internal force are studied under live loads, temperature loads.etc, consequently, the systemic research results on mechanical behaviors of single pylon cable-stayed bridge systems are fined. The research objects include the bridges with common system, combined system and the system of oblique tower. The common system is studied in two sorts: symmetrical and asymmetrical; The study of the combined system emphasize on the combination between single pylon cable stayed bridge and continuous beams, and the combination between single pylon cable stayed bridge and T rigid frame; with the example of a existing single oblique pylon cable-stayed, the mechanical behaviors of such single pylon cable-stayed bridges as without backstays are summarized in the study on the system of oblique pylon.(3) In single pylon cable -stayed bridges, the length of" unsupported" deck adjacent to the end supports are the important parameters that affect the internal forces and stiffness of the structure. The influences of the above-mentioned parameters are studied both in the symmetrical system and the asymmetrical system. Besides, the stiffness ratio between girder and tower and its influences on the internal forces are described in the dissertation.