176 CAMBRIA STEEL. 



EXPLANATIONS OF THE TABLES OF PROPERTIES 

 OF STANDARD AND SPECIAL I-BEAMS, STAND- 

 ARD AND SPECIAL CHANNELS, AND STANDARD 

 AND SPECIAL ANGLES WITH EQUAL AND UN- 

 EQUAL LEGS. 



PROPERTIES OF I-BEAMS. 



PAGES 182 TO 185 INCLUSIVE. 



The figures or values in the various columns give the section 

 numbers, dimensions, weights, areas and properties of the sec- 

 tions as noted in the different headings. 



The columns which require special explanation are as follows: 



SECTION MODULUS Column 8. 



This is obtained from the moment of inertia in column 7 by 

 dividing it by the distance from the neutral axis to the most 

 remote fibre, which in this case is one-half the depth of the beam. 



COEFFICIENTS OF STRENGTH Columns 13 and 14. 



The coefficients of strength F and F' have been computed for 

 fibre stresses of 16 000 and 12 500 pounds per square inch respect- 

 ively, as stated in the headings of the columns, and are the safe 

 loads in pounds uniformly distributed, including its own weight, 

 for a beam one foot long. Thus the safe load for any span may 

 be obtained by dividing the proper coefficient by the length of 

 the span in feet. 



The coefficients of strength were obtained from the following 

 formulae: 



.F = f X16000XS 

 F 7 = f X 12 500 X S 



in which S is the section modulus. 



