Define Underwater Inspection of steel or cast iron structures?

Underwater Inspection of steel/cast iron structures may be carried out as under:

i. Start the inspection at splash/tidal zone and proceed to 30 cm below the mean low water level. This is where most mechanical and corrosion damage is normally found.

ii. Inspect general condition of steel/cast iron. If there is marine growth, clean all marine growth from a 30 cm square section of pile and inspect for rust, scale and any pitting.

iii. Sound the surface with a hammer to detect any scaled steel or hollow areas. iv. In case of cast iron, check for graphite with knife or knocking by hammer.

v. Descend, visually inspecting the structure and sounding with a hammer where there is minimal marine growth.

vi. Record other visual observations such as coating condition (peeling, blistering, and erosion). Closely inspect splices for loss of weld material and looseness.

vii. Record the extent corrosion, structural damage, or any other significant observation, using callipers and scales to measure the thickness of steel flanges, webs, and plates, and ultrasonic meters to measure the thickness of steel pipe piles and sheet piling.

viii. Take still/video photographs showing general condition of the structure. Also take close up photographs of damaged areas.