Design Theory And Method On A Flexible Suspension Bridge

The flexible suspension bridge can fully display the characteristic of great drawn intensity of cable wire with high strength. we can construct a long-span bridge, but the bridge do not need very high pylon. The structure of the bridge deck is simple and easy to process; the amount of steel consumed is low; the construct and safeguard is convenient; the bridge type is beautiful-, the fabrication cost is low, etc. So it has the extensive prospect of application in the countryside and resort. The design theory of suspension bridge often pays much attention to the research of the large and middle-scale rigid bridge type. Regarding to the flexible suspension bridge, it has some imperfect places from theory to practice.Under loading function, main cable of the flexible suspension bridge will produce the changes of the geometry shape and internal force. So, To correctly analyse the stress situation of the main cable becomes the key to the design of the flexible suspension bridge. The traditional design method to main cable is supposition that the load is distributed evenly in the horizontal direction, and the main cable shape is a parabola, the parabola algorithm was used to calculate the design of the main cable on the project. But after suspension bridge completed, as to main cable, the load of which are its weight along suspension cable and partially centralism load which is transmitted by the hangers. So, the traditional computation theory of main cable design and the actual stress of main cable are much different, especially aberration bridge. It is apt to cause greater error.By studying the stress and line shape under its weight along suspension curve and partially centralism load which is transmitted by the hangers, the main cable between two hangers is only stressed by its weight. It is accorded with generally acknowledged suspension line shape—catenary. According to stress balance and inclusive distortion terms, the catenary algorithm and Newton iteration are adopted to accurately calculate the line shape of the completed bridge and the length of cable, and also used to set up the mathematics models of the suspension design system.Based on the established mathematics models, the computer aided design system of the flexible suspension bridge was developed with the aid of software Visual Basic 6.0, AutoCAD and its second development tool—VBA. It includes two subsystems—suspension system design and cartography system of the bridge type. The systematic interface is friendly and easy to operate. It can realize the design parameter inputting; the suspension system design calculating; the security inspecting; the arrangement figure of the bridge type drawing, etc. It also solve the computerization to the design of the flexible suspension bridge, avoid convoluted and...