SCOPE OF WORK
The
Contractor shall design, furnish and install prestressed concrete corrugated
sheet piles for intake and discharge channel work as indicated in Book II,
"Summary Scope of Work ", in the Technical Specification refers to “General
Civil and Architectural Design Requirements" and as shown on the drawings.
The work
shall include furnishing all labor, material and equipment necessary to
fabricate, deliver, install and test all sheet piles, complete.
CODES AND STANDARDS
Contractor shall comply with the
requirements of Book II, "Codes and Standards".
The following codes and
standards extracted from Book II, "Codes and Standards" are
specifically applicable to the design, manufacture and testing of the work included
in the Specification:
JIS ..................... Japan
Industrial Standard
ASTM ..................... American
Society for Testing and Materials
ACI American Concrete Institute
DESIGN REQUIREMENTS
GENERAL
The
bid of the offer drawing provided shows the conceptual design of sheet pile and
minimum size of the length required as the result of preliminary design
performed by the Owner.
The
Contractor shall be fully responsible to provide sufficient size and length of
prestressed concrete corrugated sheet pile to withstand the loads such as soil
pressure, static and dynamic force of the ocean wave and others imposed on this
structure. However, the requirement specified in sub clause refers to ‘LOADS’
below as a minimum shall be fulfilled by the Contractor.
LOADS
The following loads shall be
considered in the design:
Static water pressure : as per calculation
Soil
pressure : based on
the specified sea bed level and dredging line as shown on the bid of the offer
drawing.
Safety
factors and load combination used in the design shall be in accordance with the
requirements in Technical Specification.
SHEET PILE HANDLING AND TRANSPORT
Length
of sheet piles shall be determined as to allow proper handling and
transportation of sheet piles, and shall be subject to Owner's approval.
Completed
sheet piles shall be transported and delivered to the site free of any damage.
LAY OUT
Contractor
shall lay out and be fully responsible for correctness of such lines and grades
and for proper execution of the work.
All
surveying shall be in accordance with Specification refers to "Surveying
and Setting Out" and "Erection and Commissioning"
PILING EQUIPMENT, INSTALLATION AND
WORKMANSHIP
The
Contractor shall submit with the bid proposal full details of the proposed pile
driving equipment and the method of carrying out the work.
At all
stages during driving, the pile shall be supported and restrained by means of
leaders, trest, temporary supports or other guide arrangements to maintain
position and alignment and to prevent buckling.
The
piling equipment and driving force used shall ensure that the piles are
installed without damage or loss of strength. If at any time in the opinion of
Owner satisfactory results cannot be obtained with the equipment furnished by
the Contractor, equipment of other rated capacity capable of driving piles to
approved elevation shall be furnished and used by Contractor at no additional
cost to the Owner.
MARKING
AND LENGTH OF PILES
Marking of Piles
Each pile shall be clearly
identified by its number in white paint at least every three meters, with a
minimum of three locations at the top, bottom and middle. The Iength shall be
marked and identified with white paint at least every meter. Intervals of 300
mm shall also be marked with paint.
Length
of Piles
The
length of the piles shall be as necessary to develop the required pile
capacity.
SETTING
OUT
The main
setting out for the piles is to be completed prior to commencement of piling.
Secondary or individual pile setting out is to be completed and agreed upon not
less than 8 hours prior to commencing work on the piles concerned. All main
setting out points, lines, stations, etc. are to be maintained safely and
undisturbed.
DRIVING
OF PILES
Pitching and Driving
Piles shall
be pitched accurately in the position and driven to the lines shown on the
approved drawings.
Piles
shall be driven using approved pile driving equipment. Where piles have to be
driven below the level of the bottom of the leaders, extension leaders shall be
fitted. The use of a follower or dolly will not be permitted except with the
approval of the Owner.
The Contractor shall ensure that
damage does not occur to the piles during driving. Protection of the entire
length of pile shall be regulated to ensure that the piles are not overstressed
during driving. Also, care shall be taken during driving to prevent and correct
any tendency of piles to twist or rotate.
All piles shall satisfy the
tolerances for position and inclination as stated herein. The deviation in
position of the as‑driven centerline of a pile or the projection of its
centerline from the pile center point as shown on the setting out drawings
shall not exceed 75 mm when measured in a horizontal direction at the defined,
level. Deviations from vertical shall not be more than 1 in 100.
If piles are installed out of
plan position or line beyond allowable tolerances, the piles shall be extracted
as requested by the Owner, to properly provide for load conditions and to avoid
overstressing of piles. Manipulation of piles to force them into proper
position or line will not be permitted. The Contractor shall be responsible to
extract and/or drive additional piles as noted above at no cost to the Owner.
Any
damaged pile shall be abandoned, replaced or repaired as approved by the Owner
at the Contractor's expense. Additional piles shall be driven as requested, to
provide for load conditions and to avoid overstressing of piles. The Contractor
shall be responsible to drive additional piles at no cost to the Owner.
TEMPORARY
PROTECTION OF PILES
The
Contractor shall ensure that all freestanding piles are temporarily braced or
stayed to prevent damage to the piles or loosening of the piles in the
supporting ground. The attachment of temporary works, such as bracing or
shuttering supports, to the permanent piles shall not be permitted.
EXTRACTION
OF PILES
When
extraction of the piles is required, it shall be carried out using efficient
extraction equipment of adequate capacity. The extraction equipment shall be
correctly positioned over the pile to minimize damage to the pile and to
prevent any major disturbance of the supporting ground.
RECORDS OF PILE CONSTRUCTION
During the course of the work,
the Contractor shall maintain a complete record of pile construction and the
Contractor shall submit to the Owner, in an approved format, a record for each
pile. Each pile record shall be submitted immediately after completion of each
pile and shall include:
Type of pile
Pile number and all principal
characteristics of the pile including dimensions.
Details of driving and
installation sequence progress, including dates, times, equipment used and
personnel (operator, engineer, etc.)
The equipment model number,
weight and rated energy.
Actual location of piles as
driven, with variations from plan locations indicated.
Variations in plumbness or
batter.
Any unusual phenomena
encountered in driving piles.
Depth and type of soil strata.