personnel measured and marked the station numbers (i.e., those used for 

 reference every 100 feet) and the suggested inspection station locations 

 with paint on the surface of the berthing facilities. These included 

 Bravo, Alpha, Delta, Small Craft, Echo, and the C2 East bulkhead. 



Bravo Wharf was the first inspection site. Ten randomly chosen 

 stations were selected. Because of time constraints on the first day 

 and port conditions, the first five stations (beginning at the northwest 

 corner and proceeding southward) were inspected. On-site calculations 

 showed that these were sufficient to provide an estimate of the sheet 

 piling thickness with a confidence of 95 percent and a precision of 

 0.025 inch. Bravo was built in 1970 and was in excellent condition with 

 the protective paint still providing corrosion resistance. 



Although 10 stations were proposed and selected for the sampling 

 inspection, FPO-1 had specified 21 stations to be inspected. NCEL pro- 

 vided an additional 11 stations to fulfill the contractual requirements. 

 Based on analysis of these "extra" samples, the conclusions from the 

 initial five samples were not altered. 



Alpha Wharf was inspected on the second day. Ten randomly chosen 

 stations were selected. However, based on the date of construction, 

 1980, a smaller sample size would have been suggested had this been an 

 inspection based on statistical sampling. Again, this wharf was in 

 excellent condition. No additional samples were needed to estimate the 

 thickness of the sheet pilings with a confidence of 95 percent and a 

 precision of 0.025 inch. 



One station was eliminated from the statistical calculation (59+22). 

 The thickness reading showed an average of 0.375 inch. All other mea- 

 surements for Alpha were near 0.500 inch. After discussion with port 

 personnel, it was determined that it was possible that 0.375-inch nominal 

 sheet pilings were mixed in with the 0.500-inch sheet pilings. During 

 the construction of Alpha, the C2 East bulkhead had sustained a failure 

 and the construction crew moved from Alpha to C2 East to repair the 

 damaged area. Since the nominal thickness of the sheet piles needed to 

 repair C2 East was 0.375 inch, most likely, one or more of the remaining 

 0.375-inch sheet piles were brought back to Alpha Wharf and used in its 

 construction. 



Delta Wharf contains four berthing areas, Dl to D4, and was con- 

 structed in 1959. To conform to FPO-1 sample requirements, 21 stations 

 were selected using the systematic sampling procedure. The amount of 

 deterioration was as much as 14 percent for the web and 11 percent for 

 the flange. The normal distribution model visually appeared to agree 

 with the observed data very well. Ten samples would have been suffi- 

 cient to estimate the range of thickness values based upon the coeffi- 

 cient of variation. Without prior inspection information and based upon 

 the age of the facility, 10 samples would have been specified for an 

 inspection by statistical procedures, as compared to the 21 actually 

 used. 



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