The Solution of Rigid Frames by the Method of Rotations

Crane girders of the plate girder type form an excellent example for the economical application of welding and, in the case of exceptionally large girders, have several advantages when compared with riveted girders. E. Ibbotson

Sir, May I reply to the letter which appeared in the December, 1949, Journal alluding to remarks I made during the discussion on Dr. Gottfeldt’s paper “ Curved Bridges, and why they should be Welded.”

Recent advances in methods of fabrication of structural steelwork have had a marked influence on the design of steel structures of all types. The rapid development of electric welding has given very wide scope to the structural designer, not only in the design of joint details but also in the design of the structural units themselves. With the need for larger areas of unrestricted floor space in modern industrial building design, very deep plate girders of large spans have become increasingly popular. Typical girders of this type recently incorporated in the New Margam Steel plant at South Wales have been described in an accompanying paper presented to the Institution by Mr. E. Ibbotson (Member). Up to the present time the main fields of application for these girders have been confined to bridges and crane girders. It is only a matter of time, however, before their usage is extended to cinemas, assembly halls and similar structures. S. Mackey and D. Brotton