CAMBBIA STEEL. 177 



COEFFICIENTS OF DEFLECTION Columns 15 and 16. 



The Coefficients of Deflection N and N' for uniform and center 

 loads, respectively, were obtained from the following formulae: 



Wl 3 PI 3 



N = -^- N' = 



76.8EI 48EI 



in which 



P and W = 1 000 pounds. 



1 = 12 inches. 



E = 29 000 000. 



I = moment of inertia about axis 1-1. 



These coefficients are, therefore, the deflections in inches of a 

 beam one foot long with a load of 1 000 pounds, hence, the deflec- 

 tion of a beam for any load and span may be obtained by multi- 

 plying the proper coefficient by the cube of the span in feet, and 

 by the number of 1 000-pound units in the given load. 



PROPERTIES OF STANDARD AND SPECIAL CHANNELS. 



PAGES 186 TO 191 INCLUSIVE. 



The various columns in the Tables of Properties of Standard 

 Channels are similar to those in the Tables of Properties of 

 I-Beams, as explained above, with the addition of column 11, 

 which gives the Section Modulus about an axis through the center 

 of gravity parallel to the web, and column 13, which gives the 

 distance of the center of gravity from the outside of the web. 



j> 



In this case the Section Modulus S' = ; the notation being 



b x 



as given at the heads of the columns. 



