Wind Analysis of Bridges by Gust Load Factor Method

Abstract

Wind is a widespread and costly natural hazard to mankind. Adequate of wind effect in design is essential for the safety and economics of structure. Wind engineering is an emerging discipline. Even though there is vast amount of literature available in this field, it is dispersed in journals and technical reports that relate to the discipline of structural engineering, fluid dynamics, mechanical engineering, atmospheric sciences, and others. Because of this dispersion architects and engineers have difficulty in leaning and understanding problems associated with wind load. The bridges are made of different materials. Timber, masonry, concrete and steel are the primary materials which are most common in the design of bridges. The timber bridges are constructed only over small spans and for temporary purpose. The masonry bridges can also be used to cover only the small spans. The ratio of permissible stress to weight for masonry is fairly small and in spans larger than about 12 m the dead load of the masonry will make its use uneconomical.

Reinforced concrete is probably the most popular material for permanent highway bridges in India. Balanced cantilever bridges and pre stressed concrete girder bridges can be used for spans up to 60 m. Concrete arch has been used for spans of 200 m. In India for railway bridges steel is used for very small spans to very large spans. Bridges are built for many purposes e.g. carrying a highway, a railway track, for support of water pipes, gas or oil pipes etc. Nearly all important bridges are built primarily for purposes of carrying a highway or railway over a river, canal, another highway or railway or some other natural or artificial obstacle.