# Beams and Girders

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BEAMS AND GIRDERS.

Only the height of the story is used, as the partition stops at the ceiling. In the above case it is assumed that the partition may go anywhere, and therefore, in some cases, may come directly over a beam, thus being entirely carried by it. If the partitions are in general located so as to come between beams, and no pro vision is desired for other possible locations, the above partition load might be reduced one-half, as a partition would then be carried by two beams. Or if the partitions came only over girders, the load

might be omitted entirely in the calculation of the beams.

In the above total dead load, it should be noted that the allow ance for steel does not include the weight of girders. This of course should not be included for the beams. In the calculation of the girders the weight of the girder itself should be added.

The calculation of dead load cannot be absolutely exact, any more than can the determination of the exact amount of live load that will have to be carried. It should always, however, be worked out in detail as above, so that as close an approximation as possible shall be made.

Tables XIV and XVI, of Part I, and Table XVII, Part II, give the weights of different materials and forms of construc tion, for use in determination of dead loads under different con ditions.

The floor arch is assumed to carry all its load vertically to the beams, and the load therefore is the product of the area and the load carried per square foot. This neglect of thrust from the arch is on the safe side as regards the determination of amount of load on the beam.

## Distribution of

Loads. The load on a girder is generally concentrated at one or more points, and involves the calculation of the reactions from the beams. Girders therefore, as a general thing, are not calculated until after the beams. A girder may also have a uniform load from one side, or from a partition or wall.