Specifications for Prefabricated
Vertical Drains
A. Description
The Wick Drain contractor
shall supply all necessary labor, equipment, and materials and perform all
installation of vertical wick drains in accordance with the details shown on
the plans and with the requirements of these specifications.
B. Materials
Materials shall be Soil Drain
707,or approved equal.
Prefabricated Vertical Drains
shall be made of newly manufactured materials from an approved manufacturer and
consist of a polypropylene core with a spun bonded non-woven filter fabric
around it.
C. Transportation and Storage
The wick drains shall be
labeled per pallet with information regarding product identification, Lot# and
manufacture date.
During transportation and storage the material
shall be kept from sunlight, mud, dirt, and weather such as a enclosed trailer
,or pallets wrapped in a tinted plastic.
D. Equipment
Drains shall be installed
with approved modern equipment of a type that will cause minimum disturbance to
the soil during installation
The wick drains shall be
installed using a mandrel or sleeve that will be advanced through the soil to
the required depth. Constant rates of advancement or static pushing is the
preferred method. A vibrator may be used in areas were static methods cannot
achieve design depths. The vibrator may only be used in cases were design
penetration cannot be achieved using full static force. A drain may be
abandoned before reaching design penetration when the rate of installation is
less than 6 inches per second with the full static force and full dynamic force
applied. Use of falling impact hammers will not be allowed. Jetting will not be
allowed, but a provision must be provided for introducing water into the top of
the mandrel. The mandrel shall protect the wick drain from tears, cuts, and
abrasions during installation.
E. Construction Requirements
Drains will be located,
numbered and staked out by the surveyor.
The wick drain contractor shall take all reasonable precautions to preserve the
stakes. The locations of the wick drains shall not deviate more than 6 inches
from the locations indicated on the drawings or directed by the engineer.
Drains shall be installed
from the working surface to the design depth shown on the plans, or to such a depth where the soil resists a reasonable
effort to further penetration.
The wick drain contractor
shall provide the Engineer with suitable means for determining the depth of a
drain at any given time.
Splices or connections to the
wick drain rolls shall be done in a workmanlike manner and so as to insure
continuity of drain material . The jacket and core shall have a minimum overlap
of 6 inches when spliced.
The installed wick drain
shall be neatly cut at its upper end with 4 to 8 inches protruding above the
working surface.
The contractor shall supply
to the Engineer at the end of each working day a total quantity of wick
installed that day.
Equipment installing wick
drains shall be checked for plumbness and not deviate more than 1 inch per foot
from vertical.
F. Pre-augering/ Obstructions
Where obstructions are
encountered below the working surface which cannot be penetrated by the installation rig, the wick drain
contractor shall complete the drain from the working surface down to the
obstruction, and notify the Engineer prior to installing any more drains. At
the direction of the Engineer and under his review, the wick drain contractor
shall attempt to install a new drain within 18” from the obstructed drain. A
maximum of two attempts shall be made as directed by the Engineer. If the drain
still cannot be installed to the design depth, the drain location shall be
abandoned and the installation rig shall move to the next location,or other
action shall be taken as directed by the Engineer.
The Wick Drain contractor
shall paid for all obstructed wick drains installed at the contract unit price.
Where augering is used, the
auger shall have a minimum outside diameter equal to the largest horizontal
dimension of the mandrel, shoe, or anchor, whichever is greater.
G. Experience
As a minimum experience
requirement, the Wick Drain contractor shall have successfully completed five
wick drain installation projects of
similar size and depths, as well as installing no less than 5,000,000 linear
feet in the past five years. The five projects shall be identified by project
name, location, project description, size, completion date, and contact name.
F. Method of measurement
Wick drains will shall be
measured by the linear foot for the full length of drain installed, including
required wick extending above the working platform.
G. Basis of payment
Payment for wick drains shall be made at the contract price per linear foot or in some cases lump sum. This price shall be full compensation for the cost of furnishing the wick drain material, installing the drain, and all tool, materials, labor, and equipment necessary.