The distance in meters from the axis of the load is plotted along the horizontal, and along the 

 vertical, the specific "sag" is plotted which, according to Bernstein, is the ratio of the length 

 vector of sag in mm to the weight of the load in tons. 



METERS 

 SO 40 3D 20 10 10 20 30 <tO 50 



1. INITIAL LOAD-" 



2. WITHIN ONE HOUR 



3. UNLOADED 

 WITHIN 10 MINUTES 

 AFTER UNLOADING 



Figure 63. Ice sag under a load with time. 



It can be seen from the figure that after loading, the vectors of sag increase (attaining, as 

 Bernstein says, double and even triple amounts in the course of three hours) and then does not in- 

 crease any more in the course of the following 9 to 10 hours. After unloading, the sag is very 

 quickly amost eradicated and only a very small residual deformation remains. 



Figure 64 is a graph of ice flexure on 29 January, 1942 for a 52 ton locomotive on a railraod 

 ice crossing of the Kuznechikha River in Archangelsk. 



SECONDS 



fO 20 30 40 50 60 70 80 90 WO 110 120 



r C I* I * I ■ ■ * v. — \ 1 1 / f t 



W 

 20 



30 

 40 



i 50 

 60 

 70- 

 80 



Figure 64. Ice flexure on the Kuznechikha River, 29 January 1942. 



194 



