0.2 



0.15 



0.1 



O 0.05 



-0.05 













































> 























g Q 



« 



-•."* 



• 



















B= 



■b"" 



• 





« 









• 



• 







e 





» 



• ej 



ra 



= . 



a 





-^ 



• 













> 



k-**. 



• 





▼ 





• 



^ 



V 



• 







y 













' ▼ 







••K 





/ 



:•' 



• 



►^ 







' 



▼>. 









X 



















▼ 



















▼ 











▼ 















2 4 6 8 10 12 

 Mean Damage, S 



14 



• Series A' a Series B' ▼ Series C Eq. 6.6 





Figure 6.6. Prediction of standard deviation of minimum cover depth as a function of 

 mean damage for Series A', B\ and C 



For Equation 6.5, the correlation coefficients were r - 0.99 for all three 

 series. Figure 6.5 and Equation 6.5 indicate that the mean cover depth decreases 

 approximately linearly vi^ith mean damage increase. The scattered values of (o^ - 0^0) 

 plotted in Figure 6.6 are of the same order of magnitude as the initial value 0^ listed 

 above. Figure 6.6 and Equation 6.6 indicate that the standard deviation 0^ representing 

 the variability of cover depth along the structure increases somewhat with damage 

 progression and then decreases as the cover depth approaches zero. It is noted that 

 Equation 6.6 overestimates Qq somewhat for Series C as can be seen in Figure 6.6. 



A failure criterion based on the normalized minimum cover depth C is 

 explored in the following. Using the lower limit of C* = (C - Q IOq in Equation 5.10, 



116 



