Since two divers were involved in the inspections, the estimated 

 times reflect the time required using two divers. The time for a single 

 diver to perform each function is about double these values. 



As an illustration of the application of the estimates of the time 

 required to inspect timber pilings based upon the multiple regression 

 analysis data, assume a sampling strategy as follows: 96 pilings are 

 inspected via Level I for assessing the presence of borer activity, and 

 30 Level II measurements are required to obtain an estimate of pile 

 diameters. To estimate the in-water time required for one diver to 

 inspect a pier with 120 bents, the following times can be derived from 

 the regression analysis: 



1. Time to inspect 96 piles using Level I 



inspection methods (96 piles x 36 s): 58 min 



2. Time to inspect 30 of the 96 piles using 



Level II inspection methods (30 x 80 s): 40 min 



3. Time to traverse about 120 bents: 260 min 



4. Time to perform other in-water activities: 8 min 



5. Total estimated time for inspection: 366 min 



(6.1 h) 



Table 8 shows the estimate of the amount of maintenance required 

 for each pier. Each pier is listed twice, once using data from the 

 smaller sample and the second time using data from the larger sample. 

 The maintenance criteria based upon the amount of area remaining for 

 each pile, as recommended by O'Neill (Ref 7), are as follows: 



(1) No maintenance if over 95 percent area remaining. 



(2) Wrap the pile if less than 95 percent but equal or greater 

 than 75 percent. While it may be interesting to determine 

 if a piling falls within this interval, the recommended 

 repair is probably not realistic since a pile falling into 

 this category may still be structurally adequate. However, 

 if the. pile has borer damage, then it may be necessary to 

 wrap the pile to prevent additional deterioration due to 

 increased borer activity. 



(3) Concrete jacket the pile if less than 75 percent but greater 

 than 50 percent. 



(4) Replace the pile if less than 50 percent area remaining. 



36 



