DESIGN OF LACING BARS. .V.'. 



.ur.i <>f the cross-section of the column, and c = the distance from the neutral axis of column 



W I 70./I t* I 

 to the extreme fiber in the plane parallel to the plane of the lacing bars. Then 



O T'C 



and W 560 Now the shear in the column will be S W/2, and the shear is 5 



c 



280 , and the stress in a lacing bar will be 280 X esc 0, where 6 = the angle made by 



c c 



tlu- 1 tar with the axis of the column. In a laced channel column the shearing stress above will be 

 t.ikfii by two lacing bars. This shows that the stresses in the lacing bars in the column with a 

 concentric loading depend upon the make-up of the column, and are independent of the length 

 of the column. 



Mr. C. C. Schneider by a somewhat different method has deduced the same formula on page 

 195 of the Report of the Royal Commission on Collapse of Quebec Bridge, 1908. 



If the column carries a direct shear in addition to the shear due to the concentric load, or if 

 the column has an eccentric load the additional shearing stresses must be considered in designing 

 the lacing. The total stress in the lacing bar will be the total shear at the section multiplied by 

 the cosec of the angle made by the lacing bar with the axis of the column. 



