CAMBBIA STEEL. 



From the Tables of Safe Loads, page 108, it is found that the 

 safe load for the beam in question is 7 580 pounds, but this value 

 is below the line which indicates the span corresponding to the 

 allowable limit of deflection. 



Substituting the proper values in the formula for obtaining the 

 reduced load corresponding to the allowable deflection, as given 

 on page 101, we have 



which is the safe load required. 



EXAMPLE III. 



Required the best arrangement of beams for the floor system of 

 a building 40 feet wide x 88 feet deep to safely support a live 

 load of 100 pounds per square foot, using 10-inch tile arches 

 resting on 12-inch I-Beams. 



The weight of the floor materials will be about 50 pounds per 

 square foot, allowing 39 pounds for the arch and 11 pounds for 

 the other materials, or a total load of 150 pounds per square foot 

 to be carried by the beams. 



From the Table of Spacing for I-Beams for a uniform load of 

 100 pounds per square foot, page 128, it is seen that 12" standard 

 I-Beams weighing 31| pounds per foot and spaced 9.6 feet apart 

 from center to center can be used with a span of 20 feet, and for a 

 load of 150 pounds per square foot the spacing will be 



9.6 X 100 A , , 4 

 -160- =6 ' 4feet - 



This will require one row of interior columns lengthwise of 

 building. 



To support the beams at the center of the building will require 

 a line of girder beams resting on the columns. Assume the 

 columns 22 feet apart, thus dividing the building into 8 bays, 

 four on each side of the center. 



The load on each girder will be 



^ X 22 X 150 = 66 000 pounds. 



