to hold the transducers and measure the transmission path length automat- 

 ically. A common data acquisition system should be developed to inter- 

 face the three instrumentation systems mentioned above and discussed in 

 this report. This system would collect and output data from each instru- 

 ment for field evaluation and later analysis. 



5. An integrated systems approach for the underwater inspection of 

 concrete structures, as shown in Figure 21, is further recommended. 

 This approach uses the underwater cleaning system developed by NCEL 

 (Ref 15) as a key element, in addition to the three instruments dis- 

 cussed in this report. The cleaning system is used to clean the con- 

 crete for Level II and Level III inspections and provide a hydraulic 

 power source to take core samples if required. The three instrumenta- 

 tion systems utilize a common data output and analysis system. Infor- 

 mation from the inspection would indicate if concrete cores were required 

 to complete the analysis of the structure. A rebar corrosion detection 

 system, under development by NCEL (Ref 16), should be integrated into 

 the underwater inspection system and, if possible, included as part of 

 the R-Meter design. 



REFERENCES 



1. Civil Engineering Laboratory. Technical Note N-1624: Inspection 

 requirements analysis and nondestructive testing technique assessment 

 for underwater inspection of waterfront facilities, by R.L. Brackett, 

 W.J. Nordell and R.D. Rail. Port Hueneme, Calif., March 1982. 



2. V.M. Malhotra. Testing hardened concrete: Nondestructive methods, 

 American Concrete Institute, Monograph No. 9. Detroit, Michigan, 1976. 



3. R.L. Brackett. "Underwater inspection of waterfront facilities." 

 The American Society of Mechnical Engineers, Publication No. 

 81-WA/0CE-5. New York, N.Y. , 1981. 



4. Naval Civil Engineering Laboratory Unpublished Report: Waterfront 

 structures underwater inspection program plan, by R.L. Brackett. Port 

 Hueneme, Calif., Feb 1984. 



5. . Contract Report: NCEL underwater computerized 



tomography inspection study, Phase I. Santa Barbara, Calif., Ametek, 

 Jun 1982. 



6. . Contract Report: Preliminary design report for the 



underwater computerized axial tomography system for inspection of 

 submerged structures. Santa Barbara, Calif., Ametek, Jun 1982. 



7. . Contract Report: Economic assessment of computerized 



axial tomography inspection of timber and concrete waterfront structures, 

 by R.R. King. San Antonio, Tex., Southwest Research Institute, Jan 1983. 



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