Marine borers are also responsible for some of the
treatment, it must be applied at some temperature
deterioration actions on timbers.
between 175 And 200 Fahrenheit. Another thing to
8-26. There are many types of marine borers, but only
remember is to avoid the use of timber hooks, cant
two general groups (mollusks and crustaceans) are
hooks, or other sharp-pointed tools when you are handing
important to us now. Borers belonging to the mollusks
treated timbers.
group enter the timber, burrow themselves, and
8-31. Most of our modern treatment plants precut
honeycomb the interior.
On the other hand, the
timbers to size and notch and bore them before
crustaceans operate by forming shallow gullies just under
treatment. This prevent the need for further treatment if
the surface.
you handle these timbers with care.
8-27. Wharf or pier construction failures are caused
8-32. So far, we have discussed the construction
either by mechanical factors or by deterioration factors.
features of wharves, piers, and quays; the special tools
No matter which is responsible, the damage must be
needed for such work; the general maintenance problems
repaired So lets take a look at some of the corrective
involved here; and the corrective repairs necessary. Now
repairs which can be made and try to determine which
let's talk about some of the ways to prevent or minimize
method we should use to repair any particular damaged
damage to these structures and safety measures which
pier.
you use in such work.
8-28. Corrective Repairs. Wharves and piers are
8-33. Preventive Maintenance Measures.
To
usually repaired by replacing the damaged part. The
adequately maintain wharves and piers, we must provide
replacement part should be of the same type of material
and maintain an appropriate preventive maintenance
as the part it is to replace. But, if failure is due to
program. This program must outline preventive measures
overloading and if it is believed that overloading will
and present specific frequencies for inspections and
recur, the structure should be reinforced or otherwise
corrective actions. Therefore, we are going to discuss the
strengthened.
methods you should use to maintain these structures. As
8-29. Failures by deterioration are the hardest to
we have explained above, wharf and per structures are
detect and correct. Failure to correctly estimate how far
damaged from wear, deterioration, insect infestation,
repairs should be carried out is one of our biggest errors.
overloading, storm damage, fire, etc However, the
This is specifically true if the failure is due to
damaging effect from these factors can be minimized if
deterioration. From a visual inspection, some timbers
we follow the procedures and precautions outlined in the
look solid and sound; but when removed, they may be
following paragraphs.
found to be hollow shells. This is primarily due to
8-34. To guard against excessive wear to decking, we
attacks by termites. Similarly, fender pile which are
must make frequent inspections and keep tracked vehicles
sound above the water line are often damaged near the
or other iron wheeled equipment from traveling over it
ground line by marine borers. For these reasons, all
Post notices of this restriction in conspicuous places. All
timbers must be carefully checked to determine their true
loose bolts and nuts found during the inspection should
condition. Two ways to do this are to hammer on
be tightened. All decking should be securely nailed at
timbers or t drive nail into them to see whether they
every joist. If decking is 3 inches thick, 60d nails or 6-
have become softened by deterioration. If you have
inch spikes should be used. If it is 4 inches thick, 7-or 8-
doubt as to the soundness of a structure, you should bore
inch spikes should be used. All planking used as decking
holes into the sides of caps and stringers. If you find the
material should be of the same thickness to give a
timber to be sound, carefully plug and paint the holes to
smooth surface.
keep out further moisture.
8-35. Fender piles should be removed and replaced
8-30. Generally speaking, the materials used for repairs
before excessive wear occurs. Normally, only hardwoods
or replacements should be of the same type and size as
(such as oak) are used for fender piles; however, if traffic
those used in the original design. However, no matter
is light, creosoted softwood piles may be used. No
what type of materials are used, you must handle them
matter what type wood is used, make sure that all chocks
with care if you intend to get maximum service. Also, to
are tightly fitted between the piles. These chocks help
stop the entrance of fungi and insect, you must re-treat
prevent the piles from rolling when rubbed by vessels. If
all low-resistant areas and broken surfaces of treated
currents are swift, fender log should be used to prevent
timbers. If cu are made in the surface of treated timbers,
damage to piles. Also, a thorough check of all timber
you should paint them with two or more coats of
and hardware should be made and any necessary
preservative compound. Now, if creosote is used for this
corrective actions taken.
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