4　Detection

4.1　General Provision

4.1.1　Defect detection of hydraulic concrete structure shall provide detailed，reliable and effective detection data and conclusion for structure quality evaluation，assessment or appraisement.

4.1.2　Detection plan and items shall be determined according to the importance and specific condition of hydraulic concrete structure，and the detection outlines shall be made.

4.1.3　Detection of hydraulic concrete structure shall be carried out according to defect condition and related requirements.

4.1.4　Defect detection includes general inspection and specific detection.

1　General inspection items include distribution of appearance defect and cracks，concrete damage and seepage，expansion joint working condition and deformation，information collection and study.Underwater detection shall also include the inspection of appearance completeness，attachments and embedded condition by sediments.Defect development history，foundation and structure deformations shall be surveyed if necessary.

2　Specific detection items include concrete crack behavior，strength，freezing-thawing condition，carbonization，and steel bar rusting，corrosion，permeability，internal defects，concrete cover thickness，structure displacement and deformation.

4.1.5　Detection personnel shall meet the following requirements:

1　Detection shall be carried out by professional personnel with related qualification.Each detection item shall be carried out by at least two persons.

2　Diver personnel shall also have the following proof documents:

1）Diver certificate；

2）Annual physical examination report.

4.1.6　Equipment and apparatuses shall be provided with product qualification，instruction，and metrological verification.

4.1.7　For underwater detection，the following principles shall be followed:

1　Diving detection for hydraulic concrete structure shall strictly comply with related national regulations for diving activity.

2　Underwater detection and on the water supervision shall be carried out synchronically.The former shall be always supervised and instructed by the latter.

3　Underwater visual check shall be carried out in conjunction with videography.