INTRODUCTION 



More than two-thirds of the facilities of the Naval Shore Establish- 

 ment are over 35 years old (nearly twice their original design life) and 

 require increasing amounts of maintenance and repair to remain operational. 

 The key to improved maintenance and repair management, readiness assess- 

 ment, and catastrophic failure prevention is improved facility inspection 

 and condition assessment. Specialized inspection techniques are required 

 to gather data on the condition of the structural elements of critical 

 waterfront facilities in a concise and objective manner. 



The high cost of conducting underwater inspections makes it economi- 

 cally infeasible to consider a complete survey of every structural element 

 in a waterfront facility during preliminary inspections intended to assess 

 the average condition and possible need for maintenance and repair. The 

 extent of these preliminary underwater inspections should be a function 

 of the degree of deterioration present in the structural elements. The 

 data obtained from such an inspection must be capable of determining the 

 condition of the facility within a predefined accuracy and level of con- 

 fidence. The inspection data must be suitable for determining both the 

 type and magnitude of maintenance and repair operations, if needed, and 

 assuring the required level of operational capability for the structure. 



To meet this requirement for an improved method of planning under- 

 water inspections, a project was initiated at the Naval Civil Engineering 

 Laboratory (NCEL) in 1983 under the sponsorship of the Naval Facilities 

 Engineering Command (NAVFAC) . The objective of this project was to 

 develop criteria to determine the minimum number of data samples required 

 to make an accurate condition assessment of waterfront structures based 

 on construction material, mission requirement, and present condition. 

 During development of these criteria, the practical procedures for apply- 

 ing the sampling criteria to actual waterfront inspections, taking into 

 consideration such factors as time, cost, and movement of dive station 

 equipment and personnel, were to be considered. 



This report presents the results of the study to develop criteria 

 and procedures for determining the optimum data sample size for under- 

 water inspections. Also presented are the results of two inspections 

 conducted under the direction of the Chesapeake Division of NAVFAC to 

 validate the criteria developed during this project. 



BACKGROUND 



In 1980, a program to address specialized facilities maintenance 

 and repair problems was initiated. The Specialized Inspection Program 

 was established under the central management of the Naval Facilities 

 Engineering Command, Maintenance Division (Code 100). The Chesapeake 

 Division (CHESDIV) was to perform underwater surveys of the Navy's 



