This loading produces a constant shear from end to end of Main Central Span.

Third. Stresses due to Impact from last load.

Fourth. Stresses due to Transferred Load on one Suspended Span. This loading produces a constant shear from end to end of Main Central span.

Fifth. Stresses due to Dead Load on Main Central Span.

Sixth. Stresses due to Advancing Live Load on Main Central Span

Seventh. Stresses due to Impact from last load.

For certain conditions some of these stresses will not need to be considered, but in other cases they will, consequently it is necessary to insert them in the lists. For instance, in the cantilever and anchor arms the sixth and seventh items will generally be found to have no influence on the sections of members, but in some cases they will, as in long-span highway bridges with light live loads.

In calculating erection stresses, the weight of the traveller must not be forgotten, as its influence on such stresses is by no means inconsiderable.

The combination of the various stresses requires both judgment and care, for some loads may or may not act together, and some produce tension while others produce compression in the same member. Again, distinction must be made between groups of stresses with and those without wind-stresses, so as to use the different intensities of working-stresses given in the specifications of Chapters XIV. and XVI. It would be too tedious to give here the various combinations of stresses for each member of each span; but it will suffice to say that the computer will have to find for each main member in the entire bridge the greatest tension when wind-stresses are included, the greatest tension when they are excluded, the greatest compression when they are included, and the greatest compression when they are excluded, taking care not to group together any stresses that cannot exist simultaneously.

The determination of  the  proper  live  load per lineal foot for  any  member  of a cantilever bridge is one requiring a little