Joints in Tubular Structures

Not the least difficulty encountered in the design and construction of the Forth Bridge was the number of joints, as will be seen all too clearly in Fig. 1. Fifty years were to elapse before welding was used to connect small diameter tubes and it became possible to construct efficient and economical tubular structures. Such structures are designed to take advantage of the favourable characteristics of tubes
in torsion, compression and tension, but the members are proportioned in accordance with the normal laws of statics, as in any other structure, The method of jointing, however, is peculiar to this form of construction. While the whole concept of tubular structures is based upon welding, bolts being used only for site connexions, it must not be imagined that the joints evolved without careful research and experiment. Finality has not been reached, either in the scope of tubular structures or in the design of joints, but it is hoped that these notes will enable structural engineers
already familiar with conventional steelwork to design the joints in all but the most unusual tubular Structures.

G. Bernard Godfrey