The graphical technique presented in this paper allows the user to draw almost any type of bridge. Bridges are created as graphical variables and can be easily manipulated. Different kinds of bridges are classified and specified according to the characteristics of the road, the piers, the superstructure and the parapets. Several examples are presented. The terminology used stems from the use of Pascal.
computer-aided design, bridges, drawings
Bridges are difficult architectural constructions to define using parameters. They are very dependent on factors which are not easy to describe, such as landscape, building materials, building techniques, and the imagination of architects and engineers. A procedure for drawing any bridge would require more than 100 parameters. The graphics technique presented in this paper allows the user to draw a great number of bridges, although not all. In particular, the following types of bridges cannot be represented by using our method: curved bridges, bascule bridges, swing bridges, corniche viaducts, masonry bridges, wooden bridges and cable-stayed bridges. If these types are excluded, about 90 per cent of bridges can be drawn using our system.
After a brief survey of bridge terminology, the BRIDGE graphics type is presented. The different possibilities are classified and detailed in four sections: the road, the piers, the superstructure and the parapets. Implementation is briefly discussed and a few examples are given.