94 CONSOLIDATED STEEL CORPORATION 



An example is given on page 95 showing the method of selecting rolled 

 H-column sections for buildings, to which reference should be made. 

 Wherever possible it is desirable to provide for the given range of loads by 

 selecting the different weights required from the variations in size offered by 

 columns of the same section. Columns thus selected can be obtained from the 

 same rolling, thereby avoiding delay in delivery. 



Abutting sections of columns, in addition to having machine squared ends, 

 should be connected by splices of sufficient size to maintain the continuity of 

 section required for preserving the rigidity of the steel frame work of the build- 

 ing or structure. The method of splicing column sections and the manner of 

 connecting beams and girders are shown by the illustrations on page 157. 

 Weights given of the various column sections do not include splices or connec- 

 tions of any kind. 



The safe loads given in the tables are for concentric or symmetrical loading. 

 When the loads are not centrally or symmetrically applied, bending is pro- 

 duced in the column, the effect of which must be considered. The unbalanced 

 bending moment of the eccentric loads about the center of the column, in 

 inch-pounds, divided by the section modulus of the column in the direction of 

 bending gives the stress in pounds per square inch produced by the bending. 

 The load on the column produces a uniform compressive stress over the whole 

 cross section to which the bending stress must be added. The sum is the maxi- 

 mum stress on the extreme fibers of the column section. 



The maximum fiber stress due to direct load and bending must not be more 

 than 25 per cent in excess of the permissible stress on the column, for the given 

 length, obtained from the formula for concentric loading, otherwise the section 

 of the column must be increased until this limit is not exceeded. 



The section modulus about each principal axis for all the sections of rolled 

 H-columns is given in the tables of their properties on pages 52-59 and 60-67, 

 by means of which the effect of eccentric loading is easily calculated and con- 

 sidered in the above manner. 



