Forth Bridge construction: Fife cantilever, showing arrangement of platforms for construction of struts and ties
Photograph of the Fife cantilever, showing arrangement of platforms for construction of struts and ties. In the way of detail pictures it would not be easy to obtain a more satisfactory view of the Fife south-east skewback and the five tubes uniting at this point than that under consideration. The vertical columns are here represented on a scale of over an eigth of an inch to the foot. As regards the arrangement of platforms for construction of struts and ties, it will be seen by reference to No. 1 that at a point on the bottom member directly under the junction made by the intersection of each strut and tie there is a lattice girder. These girders are known as vertical ties, and in the permanent structure serve the purpose of preventing any sag in the lengths of the bottom member. During the erection these ties were temporarily utilised in the manner shown in this picture, where two of them appear about 3 inches from the outer end of bottom member. Between these a girder of somewhat solid appearance was constructed corresponding to some extent to the box girders used in the main column for lifting, and in fact working parallel to them. Upon the ends of these girders rest others larger in construction and running in the same plane as tubes below. Beneath the former were placed lifting jacks. The end of the platform butting on to the vertical column was operated upon by jacks on the platform above, and as the struts and ties progressed the girders were drawn up at one end and thrust the other, this operation being repeated till nearly the height of rail level was reached, where they are shown at their full height. Transcription from: Philip Phillips, 'The Forth Railway Bridge', Edinburgh, 1890.