Method Statement for Breakwater

What is the Method Statement for Breakwater?

A Method Statement for Breakwater construction details a systematic approach outlining the step-by-step processes and procedures for the assembly of a breakwater, a structure designed to protect coastlines or anchorages from the force of waves.

The statement ensures safety and efficiency while accounting for environmental factors and is tailored to mitigate potential damages from weather conditions, ensuring the structural integrity of the breakwater during and after construction.

Project Description

This project involves constructing a protective seawall off the coast of (Name of Project Location).

Spanning a rough length of 700.00 linear meters, the breakwater’s design includes a mix of rocks of varying sizes, detailed as follows:

• Heavier Armor/Primary rocks at the Head section – averaging 5.20 tons each.
• Armor/Primary rocks along the main body – averaging 4.00 tons each.
• Secondary/Supportive rocks at the Head section – approximately 540 kilograms each.
• Secondary/Supportive rocks along the main body – roughly 400 kilograms each.
• Core rocks, consisting of medium-sized stones, each weighing between 5 and 20 kilograms.

The total rock volume required for the breakwater’s full stretch is estimated around 200,000 m3.

Key Equipment Utilization

Manpower Requirements

• Single Project Manager
• One person for Quality Control
• One Safety Manager
• A singular Project Engineer
• One Surveyor
• An Office Engineer – 1
• A lone Foreman
• Foursome of Backhoe/Loader Operators
• One Crane Operator
• Two sets of Boat Captains and their Crews
• Two sets of Barge Patrons and their Crews
• One Diving Supervisor
• A team of eight Divers
• Six Rigging Specialists
• A couple of Welders

Staffing for Operation

• One Speed Boat Navigator
• Four Individuals to drive Dump Trucks
• Single Elf Transport Operator
• One Service Pickup Chauffeur
• Eight General Labor Personnel

Project Evaluation

Preliminary evaluation and surveying including seabed profiling will initially be carried out by our engineering team alongside a certified land surveyor to grasp the existing marine conditions.

Reference points and guideline markers will be put into place. Not fewer than six visual markers will be positioned on land for accurate leveling. To keep track of the water’s height anytime, a static tide gauge will be permanently placed in a strategic spot. The bathymetric study will progress with depth sounding at every 5-meter mark in both directions.

Construction Methodology

Logistics for Materials

Supply of rock materials will be provided by the owner. Anticipating a consistent availability of at least 900 cubic meters of rocks each day for project application, we calculate the monthly installment capacity to be close to 27,000 cubic meters.

To maintain the workflow unimpeded, we anticipate keeping a one-month inventory of assorted rock types on-site, totaling around 27,000 cubic meters at any given point.

Transportation of these materials will occur via terrestrial vehicles or marine barges. Subsequently, rocks will be transferred to the staging ground next to the scheduled breakwater area on Alphaland’s premises.

From here, four dump trucks along with terrestrial backhoe loaders will relocate the materials onto barges, which will be propelled to the assembly zone by the 400hp tugboats.

Seabed Foundation Preparation

Subsequent to the marking of pivotal positions and outlining the breakwater footprint, the seabed foundation will be made ready by diving personnel outfitted with full diving apparatus. Utilizing either a jet pump or compressor equipped with an extended nozzle, the divers will methodically even out the floor, eradicating obstacles and surfacing debris in the process.

Development of Temporary Ramp

A temporary ramp is to be erected at the end/base of the proposed breakwater, as indicated in the drawing.

Integrating the Current Seawall with the Projected Breakwater

The placement of geotextile layers will initiate at the base of the present seawall defenses as illustrated in the accompanying diagram. It’s essential to layer the top of the existing stone armor with a bed of crushed gravel or diminutive stones to a depth of 20 centimeters, thereby providing a stable foundation for the geotextile material.

Installation Technique for Geotextile Fabrics

Geotextile fabrics are conveniently provided in roll form, each spanning a breadth of 5 meters. These will be stitched into larger sections apt for direct deployment over the ocean’s substrate. The stitching work will transpire on a suitably vast and even terrain adjacent to the project area.

Rolls of geotextile will be unfolded and adjoined with a 15-centimeter margin as per manufacturer’s specifications to form an extensive matting. Subsequently, this matting will be coiled again onto a specially made reel that’s mounted on the rear of a deck barge.

These geotextile sheets will be methodically placed along the breakwater’s extent. The foremost edge of the geotextile will be fastened to the ocean floor by a team of divers employing nailers (6mm diameter x 500mm length) positioned at 1.5-meter intervals, and will then be promptly covered with either sandbags or weighty stones.

As the barge advances, it will unfurl the fabric from the reel; this action is to be immediately succeeded by the manual distribution of sandbags and rocks to serve as ballasts, evenly scattered across the geotextile’s surface. This ensures the fabric remains submerged, correctly aligned, and in its intended position.

For further information, please refer to the manufacturer endorsed methodology.

Placement of Settlement Plates

Position settlement plates at pre-defined sites following the specified designs. Distribute a layer of gravel, between 100 and 150 millimeters in thickness, underneath the gauges to serve as a stable base and buffer layer above the sub geotextile. Routine measurements of the gauge will be conducted to track any subsidence with precision.

Arrangement of 600mm Thick Rock Layers

Subsequent to the positioning and securing of the geotextile, the addition of 600 millimeters deep rock layers comprised of core material will commence. In an effort to limit sediment displacement, the initial installment of these layers will take place at the geotextile’s edges, covering roughly a quarter of its width.

The central portion of the bedding is to be completed afterward. The distribution of these layers will be facilitated by a long-arm excavator operated from atop a deck barge.

For the detailed application sequence, see the layering strategy under:

Geotextile at Base Width of Breakwater

First Phase

Second Phase

Placement of Guide Rocks and Toe/Berm

Deploying weighty guide rocks (around 1 ton in weight each) will be executed meticulously along the edges of the core material foundation and the protective base structure by employing a crane barge.

These stones serve a dual purpose: stationing themselves as boundary markers and providing directional assistance during the dissemination and shaping of core and secondary aggregates, as well as the protective base itself.

Completion of the inner boundary around the breakwater’s foundational perimeter precedes the application of rocks for toe, also placed by crane-equipped barges.

Deployment of Core Materials and Intermediate Rock Layers

Once a substantial number of alignment stones and structural base components have been established, laying of core aggregates will ensue. In the initial phase, dump trucks accompanied by a long arm excavator (utilizing an end-tipping technique) will be utilized for placement.

This machinery will also be responsible for sculpting the dumped aggregates into the requisite incline. Commencement of this process should consistently alternate from the farthest margins inward to the midsection, adhering to the following sequence:

First Sequence:

Second Sequence:

During the trimming phase and with the method of direct unloading, ensure there is ample room to facilitate the loading and offloading maneuvers of haulage vehicles, as well as the operational area required for an excavator during the reshaping process.

Pipe Deployment

Concurrent with the addition of core stones, initiate the embedding of 1000mm diameter steel piping following the details highlighted in the project’s plans and standards. It is critical during the backfilling to exercise extreme caution to prevent any distortion or harm to the pipes, especially while positioning the protective armor stones.

Placing of Protective Layer Stones (Secondary and Principal Rock Layers)

Regarding the lower segments of the wave barrier, all protective stonework will be methodically placed with a collaborative effort involving barges and cranes. For higher elevations, a combination of an excavator and crane will streamline the trimming process. Installation commences from the interior edge of the Structural Base, with individual stones being positioned sequentially via crane.

Precision placement will be overseen by expert divers to guarantee proper interlock and to achieve the desired density per square meter. Stones should be orientated so that their longest axis is nearly perpendicular to the slope’s surface.

Upon the crest of the barrier reaching above the average water level, an excavator will then be station atop the structure to conclude the sculpting efforts. Throughout these stages, periodic measurements with sounding chains and land-based target verifications will be conducted to ascertain adherence to the design specifications.

Rock Material Laying Sequence

First Sequence:

Commence by positioning core materials ranging from Station 0+00 to Station 0+20 to generate a provisional incline for machinery, as depicted in the scheme.

Second Sequence:

With the advancement of the core stone deposits, immediately proceed to overlay them with intermediate rock layers.

Third Sequence:

Following the progression of both the core and intermediate stone installations, commence with the placement of the primary protective stone layer. Continue this process up to the terminal point of the wave breaker. The preliminary protective stone layer will act as an initial safeguard against atmospheric variations and maritime conditions.

Last Sequence:

Upon completion of the inaugural protective stone layer extending to the wave breaker’s extremity, operations will recommence from Station 0. The task will involve perfecting the upper layer of intermediate stones in addition to the definitive protective stone layer, bringing it to the crest’s layer. Progression shall be made from Station 0 towards the tip. This includes refining the assembly to its terminal incline and elevation.

Daily Design Conditions

The array of day-to-day meteorological elements, such as wind, wave patterns, tidal motion, and water elevation, have divergent effects on construction activities when contrasted with the theoretical design scenarios that predominantly account for severe events. Recognizing the dangers posed to structures in mid-construction phases, regular day-to-day weather patterns take precedence over infrequent extremes.

Relatively moderate conditions, such as gentle wind and waves or minor storm surges, also pose a threat of damage. As an illustration, a breakwater in an intermediate stage with only its core constituents might withstand a brief surge of waves peaking at 2 meters, triggered by strong gusts. Nevertheless, should a storm persist beyond 24 hours, the likelihood of substantial destruction increases considerably.

This necessitates early reinforcements of core and intermediate stone layers with protective outer stones, in anticipation of sudden meteorological shifts.

Maintenance of Marine Traffic

A dedicated workboat will be employed to ensure the security and management of sea vessels during the duration of the construction activity.

Daily Construction Documentation

A comprehensive daily log will be maintained to document various aspects of the operation, summarized as follows:

• Report of daily operations on-site
• Ledger of daily advancement in works
• Inventory of daily utilized equipment
• Tally of daily workforce deployment
• Account of notable daily occurrences

Safety and Environment

The Method Statement for Breakwater construction will typically outline various safety precautions to protect workers, the environment, and the integrity of the structure being built.

Key safety measures may include:

1. Personal Protective Equipment (PPE): Ensuring all staff on site are equipped with the appropriate PPE, such as helmets, safety boots, gloves, high-visibility clothing, and life jackets when working near or on the water.
2. Training and Induction: Providing comprehensive training and safety induction for all personnel on the specific risks associated with breakwater construction and the measures in place to mitigate these risks.
3. Access Controls: Setting up secure site boundaries and controlled access points to prevent unauthorized entry and to manage the movement of machinery and materials.
4. Equipment and Machinery Safety: Regularly inspecting and maintaining all construction machinery and equipment, ensuring that they are operated by qualified personnel.
5. Weather Monitoring: Continuously monitoring weather conditions and being prepared to adjust work schedules to avoid operations during adverse weather that could put workers at risk or damage the partly finished structure.
6. Emergency Response Plan: Establishing a clear emergency response plan, including evacuation routes, muster points, and procedures for incidents such as personnel falling into the water or structural collapses.
7. Environmental Protection: Implementing measures to prevent pollution, such as containing runoff, Proper disposal of waste materials, and protecting marine life.
8. Risk Assessment: Performing regular risk assessments to identify potential hazards and revise safety procedures as necessary.
9. Communication: Ensuring clear and effective communication across the site, including the use of radios, signage, and alarms to alert workers of any immediate dangers.
10. First Aid and Medical Facilities: Providing accessible first aid kits, trained medical personnel, and facilities on-site to address any injuries or medical emergencies promptly.

Safety is of paramount importance in any construction project, and a comprehensive approach to hazard identification and risk management is essential to prevent accidents during the construction of breakwaters.

Common personal protective equipment (PPE) used during breakwater construction

During breakwater construction, where workers might face a mix of standard construction hazards and specific risks associated with marine environments, the following PPE are commonly used:

1. Safety Helmets: Hard hats to protect against falling objects and bumping head on fixed objects.
2. Safety Boots: Steel-toe boots providing protection for the feet against heavy falling or rolling objects and preventing slips or falls on wet or uneven terrain.
3. Gloves: Heavy-duty work gloves to protect hands from abrasions, cuts, and exposure to harmful substances.
4. High-Visibility Clothing: Reflective vests or jackets to ensure workers are clearly visible, reducing the risk of accidents in busy construction areas or in low-light conditions.
5. Life Jackets or Personal Flotation Devices: To be used when working near or on water to provide flotation in the case of falling in.
6. Eye Protection: Safety glasses or goggles to shield eyes from flying debris, dust, and splashes.
7. Ear Protection: Ear muffs or plugs to protect hearing in areas with high noise levels from construction equipment.
8. Respiratory Protection: Masks or respirators in situations where workers might be exposed to dust, fumes, or other respiratory hazards.
9. Protective Clothing: Sometimes full body suits or particular fabrics that resist abrasion and tearing, especially when working with sharp materials or in potentially hazardous environments.
10. Fall Protection Equipment: Safety harnesses, lanyards, and anchorage points to prevent falls from heights or to halt a fall in progress.

It’s important to note that the required PPE can vary based on the specific construction site risks, and should always be used in accordance with the safety regulations and site-specific safety plans.

Quality Control and Quality Assurance

The quality control (QC) and quality assurance (QA) aspects of a Method Statement for Breakwater construction are critical components to ensure the structure is built to specifications and will perform as designed. The QC and QA processes might include the following elements:

Quality Control

1. Material Testing: Before and during construction, materials such as rocks, geotextiles, and concrete should be tested for quality and durability.
2. Inspection and Monitoring: Regular inspection of work by a qualified QC team to ensure it conforms to the design, using checklists and predefined criteria for acceptance.
3. Documentation: Maintaining accurate records of all inspections, tests, and corrective actions taken.
4. Corrective Actions: Implementing procedures for addressing any issues that arise during construction, such as deviations from the Method Statement or material defects.
5. As-Built Surveys: Performing surveys during and upon completion of the construction project to confirm that the structure conforms to the design dimensions and positions.
6. Performance Testing: Conducting tests to ensure the functionality of the breakwater, such as wave simulation trials.
7. Staff Training: Making sure all personnel involved in QC are trained in quality standards and the specific requirements of the project.

Quality Assurance

1. Design Verification: Ensure the breakwater design meets all required specifications and standards before construction begins.
2. Material Specifications: All materials used in the construction must meet the quality standards and be suitable for marine construction, as specified in the design.
3. Supplier Evaluation: Evaluating and selecting suppliers and subcontractors based on their ability to provide materials and services that meet the required quality standards.
4. Quality Assurance Plan: Developing a QA plan that defines the quality objectives, the responsibilities of personnel, and the frequency of inspections and tests.

Together, QA and QC help to ensure that the construction of the breakwater not only follows the written methodology closely but also results in a finished product that provides the necessary protection against wave action and stands the test of time. Each element is interdependent and critical for achieving the desired level of quality in the finished breakwater.

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