Hence the moment of the load on Am at C is wy0m, and the moment of a uniform load over any portion of the girder is w X the area of the influence curve Ip' G' E ' under that portion.
A main girder consists of an upper and lower flange, boom or chord and a vertical web.
The Victoria Falls bridge over the Zambezi, designed by Sir Douglas Fox, and completed in 1905, is a combination of girder and arch having a total length of 650 ft.
If the load is in the bay D'E' and is carried by a rail girder which distributes it to cross girders at D'E', the part of the influence line under this bay is altered.
For spans over 75 ft., expansion due to change of temperature is provided for by carrying one end of each chain girder on rollers placed between the bearing-plate on the girder and the bed-plate on the pier or abutment.
Each girder is 1511 ft.
The centre girder may be built on the cantilevers and rolled into place or lifted from the water-level.
The stiffening girder, constructed chiefly of timber, was a box-shaped braced girder 18 ft.
In some girder -1 o bridges the members are connected entirely by riveting, in others the principal members are con nected by pin joints.
The girder spans are 525 ft., the cantilever spans 547 ft., and the shore spans 201 ft.