STRENGTH OF CORRUGATED 



231 



Table XVIII. The coefficient C in column 8 depends on the angle that 

 the metal makes with the horizontal axis and varies as follows : angle 

 of 30, C 0.278 ; 45, C 0.293 ; 60, C = 0.312, and for 90, C = 

 0.393- 



TABLE XVIII. 



SUMMARY OF EXPERIMENTS TO DETERMINE THE STRENGTH OF COR- 

 RUGATED STEEL.* 



The actual breaking load agrees in most cases more closely with 

 Gage's formula than with Rankine's, although the latter is more often 

 on the safe side. 



Purlins are commonly spaced for a safe load of 30 Ibs. per square 

 foot as given in Fig. 112; if the purlins are spaced farther apart than 

 this, the steel will deflect a dangerous amount when walked on, and will 

 leak snow and rain. Girts should be spaced for a safe load of about 25 

 Ibs. per square foot. From an inspection of Fig. 112, it is evident that 

 corrugated steel lighter than No. 24 is of little use for mill buildings. 



*For details of experiments see article by Ralph H. Gage, in the Technograph, 

 No. 17. 



