19 June 2001
Figure 5-15 Concrete Structures and Attachments (Below Water) Checklist
___ Inspect the structure beginning in the splash/tidal zone. This is where most
mechanical and biological damage is normally found.
___ Clear a section about 40 to 60 cm (16 to 24 inches) in length of all marine
___ Visually inspect this area for cracks with rust stain, spalling or impact
damage, and exposed reinforcing steel.
___ Sound the cleaned area with a hammer to detect any loose layers of
concrete or hollow spots in the pile or structure. A sharp ringing noise
indicates sound concrete. A soft surface will be detected, not only by a
sound change, but also by a change in the rebound, or feel, of the hammer.
A thud or hollow sound indicates a delaminated layer of concrete, most
likely from corrosion of steel reinforcement.
___ Visually inspect the pile or structure where marine growth is minimal, and
sound with a hammer.
___ Inspect, in greater detail, the base of mass concrete structures, such as
retaining walls and foundations. These structures are prone to
undermining by wave and current action, which, if not rectified, could lead
to failure of the structure.
___ At the bottom, record the water depth along with any observations of
damage on a Plexiglas slate.
___ After returning to the surface, immediately record all information into the