METHOD STATEMENT FOR MARINE WORKS.
This method statement describes in brief the broad sequence
and method for excavation/removal of unsuitable beach materials, beach sand
works, groynes construction and floating pontoon works to be carried out for
the completion of the marine works. The
overall operations would be so programmed to comply with all contract
specifications, achieve project milestones, and accommodate Engineers concerns
and to ensure that personnel and equipment resources are optimally utilized,
and construction is completed within the stipulated time in the allocated
budget.
This method statement is preliminary and is meant for tender
submission. This will be finalized on
award, incorporating Client’s comments, if any.
SCOPE OF WORK.
The main contracting shall perform the site works for the
completion of marine works.
The base scope of work shall include but not limited to the
following:
(a) excavation
/ removal of unsuitable beach materials
(b) beach sand
works
(c) groynes
construction
(d) floating
pontoon works
(e) navigation
buoys installation
(f) submission
of drawings and other relevant documents
GENERAL CONSTRUCTION ARRANGEMENT.
All activities, equipment, manpower, etc., to be used into
the works, will be performed, checked, supplied, stored and handled in
accordance with the prevailing codes, standard, specifications, design
requirements, drawings, etc.
Parts of these specifications, instructions and rules are or
will be included in the following documents.
a) Project
Quality Plan
b) Method
statements
c) Project
HSE Plan
d) Guidelines
from concerned Authorities, etc.,
Construction Preparation.
Construction preparation works shall mainly include
setting-up of site facilities and other related facilities for equipment
laydown yards, maintenance workshops etc., all as per our qualification.
MOBILIZATION.
Based on the agreed contract document and work schedule, the
Subcontractor will mobilize all relevant personnel, plant and equipment to
site. Personnel and equipment to be mobilized might come from various locations
within the Middle East, consequently, the lead times required will vary.
CONSTRUCTION METHOD.
The following methods are based on our experience in
executing similar types of operations and on the information available during
the tender stage. It is presented here as an indicative procedure only.
On award of a Contract, the method to be used may be subject
to adaptation or alteration to suit the prevailing work environment, conditions
and operational circumstances. The following sections will describe the major
construction activities.
Setting out & Survey Works.
After the detailed review of site layout plans and
associated drawings, a thorough site/ marine survey shall be conducted to
determine and to confirm the permanent reference points existing around the
proposed work area. This activity will be done in coordination with the Client/
Engineer Representative. Necessary care will be taken to ensure all reference
points are approved and correct.
During the handover of the site, reference points/
benchmarks will be established and permanently located. These points shall be
marked on drawings and reflected in shop/construction drawings as well as in
as-built drawings. The Geotechnical, Bathymetric, Topographical, Marine Surveys
and Investigation, etc. (if required) will be carried out by a specialist
agency to ascertain soil conditions as per the contract documents requirements.
Beach Development.
Silt Curtain Installation Works.
Connection of Silt Curtain.
For ease of transport and handling, silt curtains are packed
and wrapped in individual bundles of 20m sections. The connection will be
performed at site to be located as close as possible to shore in a location
which allows for the curtain to be towed offshore using an appropriate boat.
Once curtains are assembled and connected, furl curtains by folding curtain
skirt and securing with rope every 1-2m.
Deployment.
Curtain furling straps should all be securely tightened
between every float section and on end points to reduce towing friction. Always
tow with both the Anchor Point and the chain ballast pocket.
According to layout for deploy by towing seaward end of
curtain into position. Curtain furling straps should remain in place until
anchored in the required position.
Anchors should be placed from the end section working
backwards towards land. It is important that anchors are placed inside of the
curtain to allow for tide and water movement (if any).
To place anchors, attach the anchor rope after the buoy to
the designated anchor point on the curtain. Attach the anchor retrieval line at
the yellow buoy to a suitable bow cleat on the boat. Reverse slowly letting the
anchor line play out until the anchor itself is suspended midway between the
curtain and the boat. Once the curtain is in position quickly release the rope
at the cleat and allow it to fall.
Once curtain is securely anchored, it may then be unfurled
by cutting the furling straps for each section.
Re-adjust anchoring if required.
Beach Excavation Works.
After completing the surveying works, the beach area shall
be excavated to the required profiles.
Excavation will be done using a long boom excavator. An
experienced labor will accompany the operations to observe the excavation
development.
The excavations will be performed to the dimensions and
elevations indicated on the approved shop drawing.
The Surveyor and Site Engineer will monitor the excavation
slopes and depths to prevent over excavation of the area and will ensure that
the excavation levels are in accordance with contract drawings and within the
tolerance limits as specified.
Unsuitable excavated materials will be removed from site to
designated dumping area offsite.
The area of excavation will be provided with adequate
barriers, signboards, advance warning signs, etc. as required.
Beach Bund Construction.
Upon obtaining the required level of excavation and prior to
commencing with the beach sand filling and profiling, a beach bund shall be
constructed within the beach limit to prevent the sand from getting
displaced/washed away by sea waves.
Beach Sand / Profiling Works.
The approved beach sand material will be brought to the site
for stockpiling at a designated area.
After achieving the desired shape and slope, the tipper
truck shall start dumping the imported beach sand within demarcated area, after
which a land-based and/or long boom excavator on barge will start laying the
material and evenly spread it over the area starting from the shallow water
depth. The second load to be dumped over the formed layer and so on until the
filling of the beach sand is completed as required.
The same equipment
will be used to profile the beach surface to the required slope and final
level.
Removal of Existing Revetment & Defense Wall.
Prior to the commencement of dismantling work, the required formalities,
approvals including as-built drawings, method statement, etc., shall be
obtained from the Company.
After the survey work, the required equipment shall be
mobilized to the site / location.
As a first step, the armor layer will be removed using
excavator bucket by land and/or marine mode.
After the armor layer, the underlayer rock material will be
removed using the same method and equipment, and finally the core materials.
All the demolished materials will be stockpiled in a
designated area and will be later disposed offsite.
After complete removal of existing revetment, beach
construction commenced.
Groyne Construction.
Excavation for Foundation.
The location of groynes shall be set out and marked by
floating buoys. This activity will be carried out by the surveyor and divers.
Excavation will be made onshore by filling required areas to
construct the bund (temporary work platform).
If a hard stratum (rock strata) is encountered during
excavation, a rock breaker will be utilized to excavate to the required levels.
Excavated / filled surfaces shall be trimmed to the required
slopes.
Geotextile fabric shall be laid and fixed in position as per
the drawings and in accordance with the manufacturer’s instructions.
Placing of Graded Rock Layer.
Dump trucks / shovel shall deliver and stockpile the rocks
on the placing area.
Material to be used shall be tested and verified in advance
by independent laboratories.
Material shall be made available on site prior to
installation.
Upon completion of geotextile laying, graded rocks will be
placed uniformly to the required layer thickness.
Surface shall be trimmed and prepared to required slope for
receiving the armor rock layer.
Placing of Armor Rock Layer.
Armor rock layer will be placed on top of the graded rock
layer to the required thickness. A backhoe and/or crawler crane with clamshell
shall be used in this activity. Armor rock shall be placed one rock at a time
with the aid of divers.
The placement of graded rock shall proceed from the head of
the groyne (offshore) to the tail (onshore).
Pontoon Construction.
The below described activities will be carried out during
the construction of boats berthing pontoons.
Pontoon Design.
Pontoon detailed design shall be done by a specialized
subcontractor.
Tubular Piles & Pile Guides Installation.
Tubular steel piles will be installed to restrain the
complete pontoon system. An array of restraint piles will be installed to
ensure integrity of the Pontoon system and piles. The steel pile external
surface, including embedded length will be applied with protective coating as
per the approved specification.
The steel tubular piles will be sealed with top plate such
that condensation and moisture will run off the surface as specified in tender.
The piles will be topped with conical shaped cap made with GRP.
The pile guides will be designed and installed to transfer
the forces arising from the wind, wave and of vessel berthing, from the
floating structure to the piles. These pile guides will be made with aluminum.
These will be fitted with low-friction rollers or pads and designed to
facilitate easy removal of the pontoon units.
Fabrication of Pontoons.
All the pontoons will be produced as per the Company
requirements. Before starting with the
production of pontoons, the design and production methodology will be submitted
for Company approval. This will include
mould structure, polystyrene placement, mould preparation, reinforcement
arrangements, compaction method, de-moulding and curing, handling, storing, and
transporting to site.
Pontoon Connections.
All fasteners and fixings for the pontoon system, fittings
and furniture will be as specified.
Installation of Floating Pontoon.
Once the piling works are completed, the Pontoons are lifted
and placed between the piles such that the pile guides on the pontoons will
easily move through the piles.
Before any lifting operation can take place, the supervisor
should ensure that all lifting tackles, chains and the crane itself are in a
good working condition, consequently, the weights of the structure being lifted
should be known so as not to exceed the safe capacity of the lifting crane.
All the lifting belts, wire rope slings and D-shackles,
etc., shall be certified and checked prior to the lifting operations.
The concrete pontoons shall be lifted using crawler crane,
after hooking the slings/ attaching hooks in the given points considered in the
pontoons for lifting. The pontoons are slowly and carefully lifted and placed
between the tubular piles.
Pontoon Bollards/ Cleats Installation.
The mooring bollard will be fixed to the pontoon to
accommodate mooring lines forces. These will be fixed to the edge of the
pontoons as per the specification.
Access Gangways Installation.
Prefabricated aluminum gangways will be installed to bridge
the gap between abutment work and the pontoon. These gangways will be
fabricated as per the project specification. The gangways will be supported on
the landward end by hinged bearings and at other end by rollers. The gangway
landing area will be protected from wear from the gangway movements by an
aluminum running plate.
Installation of Utilities & Accessories.
The exact location for the utilities and accessories such as
electricity and water supply bollards, light pedestals, safety pedestals,
stepladders and boat mooring bollards will be measured and installed in
accordance with the approved shop drawings. All electrical cables and water
hose pipes shall be fixed according to relevant authority standards.
Fender / Rubbing Strips Installation.
Fenders/ rubbing strips will be fixed to the sides of the
pontoon to minimize vessel impact, chafing and abrasion of berthed craft and
pontoon edges. Prior to installing it, Client’s material approval shall be
obtained.