METHOD STATEMENT FOR CW PIPE LINE CIVIL WORK

The purpose of this method is to describe the methodology involved in construction work for the CW Pipe line item and to detail out the steps to be taken in order to meet the technical requirements of VP1 BOT Thermal Power Plant

PREFACE

The purpose of this method is to describe the methodology involved in construction work for the

CW Pipe line item and to detail out the steps to be taken in order to meet the technical requirements ofVP1 BOT Thermal Power Plant

 Project Van Phong 1 BOT Thermal Power Plant

 Company/Owner Van Phong Power company limited(VPCL)

MANPOWER & EQUIPMENT

• Manpower mobilized for construction of the Boiler are listed as followings:

• Equipment mobilized for construction of the Boiler are listed as followings:

No Equipment Unit Quantity Capacity

RESPONSIBILITIES AND ORGANIZATION

• It is overall responsibility of Site Manager to organize resources prior to perform construction activities as per project specification in compliance with the quality, schedule & safety requirements

• EHS Manager will ensure in coordination with Site Engineer that all measure/construction taken shall be maintained till completion of job

• It is the responsibility of Construction Manager/Site Engineer that construction activities are executed according to the relevant project specification in compliance with the quality, schedule & safety requirements

• Contractor will ensure that all works are performed safely according to the attachment

• The relevant contractor Supervisor will ensure that the work is carried out in accordance with this method statement and project specification

• The QC Inspector will ensure that the work is executed according to the requirements of quality dossier are fulfilled

VAN PHONG 1 BOT THERMAL POWER PLANT PROJECT

PROCEDURE AND SEQUENCE

SEQUENCE: Divide CW Pipe line to 6 Zone, Direction of executing from north side to south side, Zone 1 to Zone 6

CONSTRUCTION WORK

Excavation

Before commencing excavation work, it is essential to establish a dike and a robust barricade system at ground level surrounding the pipeline The slope ratio should be maintained at 1H:0.5V, and there must be a minimum distance of 2 meters between the barricade and the edge of the excavation.

• Width of the trench shall not be less than the outer diameter of the pipe addition 500 mm on either side as following design drawing

• Soil will be cut by excavator crawler, transportation by dump truck

• Always arranging watchman for each excavator The standing position of the watch man must be appropriate and outside of the rotation of the excavator

• Regularly using auto level or/and total station surveys bottom of trench in compliance the design drawing

A sump pit for de-watering should be positioned at the bottom of the trench, utilizing an electrical pump to effectively remove water The sump pit and human access route must be located adjacent to the encasement site, ensuring they are no more than 150 meters apart.

• If there is any concern of soil condition during excavation time, contractor can make more slope, maximum 1:1

Typical of section for human access way and sump pit for de-watering Access way for equipment will be arranged along the next excavation area on excavating period

Sand bedding

Before placing sand bedding, it's essential to inspect the trench for large stones or any debris left from excavation Additionally, the trench must be kept free of water to ensure proper installation.

Fill materials must be evenly laid, spread, and leveled using a bulldozer, followed by compaction with a roller compactor to achieve the specified density It is essential to maintain the moisture content of the fill material within +/- 2 percent of the optimum level If necessary, clean water should be added using a spray water truck, or the fill material can be dried to ensure the optimal moisture content is maintained.

• Use Crawler excavator put sand material into bottom of trench

• Levelling by bulldozer and worker shall be finishing in difficult area if necessary

Backfilling

• The filling shall commence only after approval by Engineer-in-charge is obtained and after the structures or pipes getting buried are approved

• Filling area surface shall be kept free from water, such as materials and debris

Backfill material must be approved by the Engineer and should be free from roots, stones, and debris It is essential to inspect the material for large stones or any other objects that may remain in the trench after the installation of piping.

• The material shall be carefully placed and packed around the pipes

• Care must be exercised to protect, pipes, joints and other features from damage due to backfilling and consolidation

• After finishing the Pipe install

Fill materials should be applied in layers, ensuring each layer is uniformly compacted to meet the Engineer's satisfaction through field density tests before adding the next layer The maximum loose thickness for each layer must not exceed 300mm.

• Field density test (FDT), Material backfill shall be carried out according with ITP General Excavation and Backfilling work

• DHI had discussed with CTCI CTCI will not block end of pipe during installation to prevent pipe floating

In addition, DHI make dike around excavation area to block ground water flowing into excavated area

• Make sure the pipe is open, if rain suddenly, water can flow in, and backfilling soil to ensure balance

- 19 - | P a g e on the both side of pipes to prevent pipe movement Two side of pipe not difference more than one layer

For effective backfilling, ensure that material is carefully placed and compacted from the bottom of trenches to a height of 600mm above the pipes Utilize appropriate equipment such as a plate vibrator or rammer for optimal compaction, and water the material as needed to achieve the desired density.

• The remaining (above on top of the pipe 600mm, above on top of the encasement 200mm) the material shall be place, compaction, leveling by dozer, roller

Concrete Encasement

• The concrete of encasement shall be pouring three times

+The first phase, install rebar and formwork and cast concrete to 580mm height Then, after chipping the surface of the concrete for construction joint

In phase 2, CC1 will pour concrete to a height of 2.3 meters, followed by the dismantling of the formwork Subsequently, backfilling will occur around the encasement in 30 cm thick layers, ensuring proper compaction to meet requirements Additionally, the surface of the concrete will be chipped to prepare for construction joints.

+Phase 3: Install rebar and formwork then cast concrete for the rest After that, carrying the remaining works to complete

• Connecting the formwork panel by connection pins and clips Checking elevation, position, and plumpness of panels Using the support pipes, steel-box, scaffold clips to fix the formwork

• Formwork must ensure close to prevent leakage of cement laitance at inspection time

• Space of pipe support is 1000mm

INSPECTION AND TESTING

• Field compaction test shall be conducted at frequency for each layer or as agreed with the Engineer

• Backfilling shall not commence until testing has been conducted to the acceptance of the Engineer

The Site Inspection and Test Plan (ITP) must be executed in accordance with the ITP for General Excavation and Backfilling Furthermore, all concrete encasement work should adhere to the ITP guidelines established for General Concrete Work.

ENVIRONMENT, HEALTH AND SAFETY (EHS)

Risk Assessment

Assessment at Risk Adverse Effect

I- PREPARATION ACTIVITIES - Manpower & Equipment & Material & Site Preparation

Site personnel /Public /Other Subcontractor s

- Unauthorized vehicles and pedestrians passing through site entrances

- Lack of suitable access/egress from the project location

- Lack of awareness and suitable control measures implemented

- No control of delivery vehicles (& drivers) travelling to, from or around site

Selecting competent individuals with the appropriate skills and talents for the job is essential It is crucial to verify and submit all necessary legal documents, including certificates and licenses, for initial induction and record-keeping Additionally, full personal protective equipment (PPE) is required to ensure safety on the job.

- Gate Entry: only authorized persons to enter site with the relevant ID card and site pass for vehicle

Each person uses their own ID card Borrow, lending, use other ID for entry is not allow and be fired off from the site if caught

* Both documents shall be given to personnel who have undertaken an EHS induction training

Movement should be restricted to designated access and egress locations, following the signage and pedestrian walkways outlined in the site traffic management plan Adhering to the specified routes ensures safety and efficiency in the site layout.

- Obeying of speed limits which be enforced for jobsite and public road

- Following and caution to warning signage which be erected on all routes Unauthorized entering or pass over the barricade is not allows

- Careful visibility allowed for vehicles entering/exiting site and the public passing-by

- No short cut allow New comer must be escorted by the old ones or supervisor

Control measures will be regularly reviewed and monitored to assess their suitability and improvements made if required

Any modifications to working conditions or operations, such as changes in sequencing, the introduction of new equipment, or the addition of new personnel, will necessitate a new risk assessment This assessment will ensure that appropriate control measures are implemented to align with the updated operational requirements.

-Fighting / argument with local peoples

- Effect on people health from hazardous fumes

- Provision of Mobil toilet at site

- Provide waste bin at site with instruction and rules

- Smoking at designated area Smoking out of designated area is prohibited

- Build campus for worker Provide necessary and other regular services to worker at camp

Lessen the directly contact chances of workers with the local people

- Gambling, drug, social violence / crime act be prohibited

- Stranger not allow to enter the site or campus without permission from the manager

All delivery vehicles (& drivers) travelling to, from or around site/

- Collision with vehicles and pedestrians due to lack of knowledge and awareness of traffic routes

- Not wearing the appropriate PPE when on site

- Bad vehicle technical quality status

- Overturning of vehicle when unloading

- Vehicle and equipment must have full legal document as Requirements and must be inspection before allowing to enter the site

All materials intended for entry onto the site must be declared and approved by the Consortium/DHI prior to access Specific items, including scaffolding and electrical materials, will undergo inspection at the entrance to ensure compliance before being allowed on-site.

Effective traffic and transportation management is crucial for site layout, as indicated by signage at the entrance and gate pass permits It is essential that transportation adheres to designated access and egress locations, ensuring clear signage and safe pedestrian walkways Shortcuts are not permitted, promoting safety and efficiency on site.

- All delivery drivers to receive brief induction & direction from gate attendant

- Delivery vehicles to be escorted by trained banks man at all times if required

- All delivery drivers to wear min PPE inclusive of safety helmet, safety shoes, safety glasses and high-visibility vest

- Traffic controllers assigned on intersections and congested areas

Any modifications to working conditions or operations, such as changes in sequencing, the introduction of new equipment, or the involvement of new personnel, will trigger a new risk assessment Following this assessment, additional control measures will be implemented to ensure safety and compliance with the updated operational requirements.

- Only certified and qualified riggers will load / unload materials during lifting operations

Materials should be organized and stored separately by type, with chemicals kept apart and accompanied by their Safety Data Sheets (SDS) It is essential to secure, isolate, label, and display signage in the storage area or on containers.

- Dust emissions into the air

- Soil contamination from vehicle/plant and equipment

- Effect on public health due to noise and dust

- Ground contamination due to oil spillage or leakage from plant /equipment & vehicles

- Traffic congestion on public roads

- Effect on adjacent buildings and residents

- Effect on local road conditions

- Effect on public health due to dust and noise

- Ground contamination due to oil spillage or leakage from plant /equipment

- Managing traffic of the project considering the rush hours on public roads

- Control of dust through regular water spray on roads

- Inspection of plant and vehicles before entering to the site

- Sheet all vehicles carrying bulk materials into and out of the site to prevent dust dispersal during transit Including transport of bulk materials inside the site

- Control of dust through regular water spray on roads

- Noise monitoring for plant & equipment, restricting the high noise equipment entering to site

- Inspection of all plant/equipment and vehicles before entering to site to check for any possible oil spill or leakage

- Sheet all vehicles carrying bulk materials into and out of the site to prevent dust dispersal during transit Including transport of bulk materials inside the site

- Regularly spray water on stripped topsoil to minimize dispersion on dust

- Secondary containment system will have a capacity of not less than 110% of the container’s storage capacity

Site personnel/Pub lic/Subcontra ctors

- Struck by moving, falling or flying objects

- Falls from working at height

- Travel only thought of designated pedestrian walkways which segregate from vehicles and work operations

Maintaining good housekeeping is essential for safety, ensuring that access and egress routes remain clear of obstructions and hazards that could lead to trips, slips, or falls It is important to adhere to designated pedestrian pathways, which will be clearly marked and guided Shortcuts are strictly prohibited, and walking on vehicle routes or transport pathways is not allowed to prevent accidents and ensure a safe environment.

- Stairways shall be of adequate width and depth with handrails installed either side

- Segregation of vehicle routes, unloading/loading areas material storage areas shall be installed on site

- All vehicle reversing shall be controlled by a banks man and audible devices

- Caution and Following signage with be used on all roads with pedestrian, crossing points

- PPE to be worn at all times

- No entry any Vehicle operating are or Lifting range or work at high on executing or confined space area without authorized or permission No pass over barricade line

- No lose focus by other act when walking such as using phone

Any alterations to working conditions or operations, such as changes in sequencing, the introduction of new equipment, or the addition of new personnel, will necessitate a fresh risk assessment Subsequently, appropriate control measures will be established to align with the updated operations.

- Over speeding of vehicles in public areas

- Following of speed limits regulation

- Information to community regarding heavy traffic movement

- Traffic controller / signalman be placed in designated position Public and local social event assisting activity

- Overturning and overloading of vehicles

- Lack of signage and speed limits

- Lack of barriers along roadways

- Lack of training and awareness

- Lack of designated parking areas

- Entering heavy equipment operated range/ high-risk activities operating

- Equipment / vehicle must pre-check its condition thought checklist before start working any damage must be repair

- Traffic management plan; informed during training and displayed on site entrance

- Only travel or driving at suitable and sufficient traffic routes (vehicle and pedestrian segregation) or through the access / egress to the jobsite No shortcut allows

- All reversing of vehicles control by a banks man

- Follow road/ access/ egress signage displayed

- Comply access routes and speed limits

- Roads of adequate width to allow traffic to move safely

- Heavy equipment designated flagman during travel

- Vehicles parking at designated areas

- Comply signboard, warning board along the route

- Speed down and careful vision when driving at Conner , cross road

- Do not using phone or calling/ answer the call during driving

- Do no pass any warning tape/ Isolated area without permission

- No Overload and stock material without tied properly

- Entering Hazard Area with High Risk Activities on Operating is prohibited

Any modifications to the working conditions or operations, such as changes in sequencing, the introduction of new equipment, or the involvement of new workers, will prompt a new risk assessment This assessment will ensure that appropriate control measures are implemented to align with the updated operational requirements.

- Traffic congestion- Dust emission into air- Generation of noise.- Oil leak

- Traffic accident due to congestion

- Effect on public health due to dust emission

- Effect on public health due to generation of noise

- Managing traffic of the project considering the rush hours on public roads

- Control dust through regular water spray on roads

- Control noise by inspection of vehicle/equipment/plants

- Every equipment must be daily check Any oil leak must be handling Oil Absorbed materials / contaminated material will be stocked properly and transfer to the 3rd Party for handling

- Spill kit / Emergency spill kit must be keep on each vehicles for sudden maintenance or oil leak accident

- Materials only stored in designated areas

- Materials to be stored according to manufacturer’s guidance and specifications

- Packaging checked prior to stacking – no loose straps/bands

- Materials shall not be stacked to high and laid on stable ground

- Material storage locations shall be segregated with adequate signage displayed

- Material storage shall be regular inspected to ensure stability and material condition

- Combustible materials shall be stored free from sources of ignition in a segregated compound with adequate signage and fire provisions

- Proper access provided on material storage area

- All cylinder must have caps and properly secured on an upright position

Any modifications to the working conditions or operations, such as changes in sequencing, the introduction of new equipment, or the involvement of new personnel, will prompt a comprehensive risk assessment This assessment will lead to the implementation of additional control measures tailored to the specific operation.

- Effect on people health from hazardous fumes

- Provision of secondary containment for liquid materials such as fuel, paint, chemicals etc

- Strictly implement the safe storage conditions and adhere to the MSDS instructions for storage

- Hazardous materials shall be stored separately and not mixed with any combustible or flammable materials

- Never use drinking water bottle as secondary containment for chemicals

- Must provide proper secondary containment dedicated for chemicals

Set up power system / temporary power devices for workshop and workforce

- Ignition of flammable gases and combustible materials

- Faulty cables, extension leads, plugs and sockets

Before commencing any electrical installation and connection work, a Permit to Work must be prepared and submitted for approval Electricians are required to possess the necessary skills, talent, and job certifications Additionally, the LOTTO procedure will be requested and applied if deemed necessary.

- Electric cable lines be marked and recorded per layout ( both upper and underground lines ) and submit to DHI

- Underground cable be buried deep down at per site procedures required and put sign board to recognize

Overhead cables crossing roads and pedestrian pathways must be clearly labeled with height markers and accompanied by caution signage Any work conducted near electrical cable lines should be strictly regulated and supervised If necessary, power should be turned off, and the electric lines relocated to ensure safety.

- Appointment of temporary electrical manager to prepare temporary electrics plan

- RCD or ELCB rated at 30mA (milliamp) to be installed and tested before use Boards must be earthed

- Only appointed persons to have entry

- Distribution board must remain locked at all times

- Sufficient transformers and socket outlets installed to prevent overload

- Leads carefully laid out and suspended away from congested areas to reduce likelihood of damage

- Maintenance undertaken by competent person

- Firefighting equipment in placed to stop any burning case happen

- Only qualified and certified (3rd Party) electrician allowed to terminate panel boards

- All distribution panel boards have warning signs, checklist and contact person attached on the front door

Any modifications to working conditions or operations, such as changes in sequencing, the introduction of new equipment, or the involvement of new personnel, will necessitate a new risk assessment This assessment will ensure that appropriate control measures are implemented to align with the operation's RRN >6 Consequently, a Job Safety and Environmental Analysis (JSEA) will be performed and attached to the required Permit to Work (PTW).

Please supplement the Job Safety Analysis for residual risk based on Doosan's risk assessment procedure and be submitted pertaining to this document for review and site implementation

Unauthorized access of public to electrical network due to lack of awareness and lack of control

Fatality or serious personal injury- Damage to property/system

[ Environment, Social & Health ]- Lock Out Tag

Our implemented system ensures that all temporary electrical networks are restricted from public access Only authorized personnel with a valid Permit to Work are permitted to enter these areas Additionally, all distribution panel boards are securely locked, with access limited to authorized individuals Hard barricades have been installed around the panel boards, accompanied by clear warning signs to enhance safety.

- Proximity of stored materials, waste materials or plant falling into excavation

- Prepare Permit to Work for every excavation activity of 1,2m of deeper Classification of underground structure and make plan to handling properly

- Supervision of work by competent person

- Adequate shoring (sloping with proper angle / benching) and battering of excavation to prevent collapse

- Edge protection installed around excavation if needed

- Safe access and egress to the bottom pit

- All materials stored at least 2m away from excavation edge

- Air monitoring inside excavation to ensure no hazardous fumes present for confined space holes

- Influx of sea water or underground water controlled by the use of pumps

- For vehicles tipping materials into excavation, stop blocks should be used at all times, banksman should be available

- All vehicle movements controlled by a banksman

- PPE must be worn at all times

Job Safety Analysis

List of All Job Steps List of All Known Hazards How to Eliminate Hazards

A Survey Works A.1 Instrument falling down and hit a workmen

A.1 Area where the instrument is to be must be well compacted

A.2 Instrument dropping to ground by accident

A.2 Focus and concentrate all the time during work execution

A.3 Stuck into the muddy area A.3 Always beware and walk on designated access A.4 Pegs splatters into the eyes A.4 Always wear safety PPE

B.1 Working operation of the equipment may cause injury to personnel due to poor visibility of the area

B.1a Must provide sufficient lightings on the entire working area

B.1b All equipment must be fitted with appropriate safety device and ensure all lights are operational not obscured by dirt and mud

B.1c Supervisor and safety personnel shall always be present for the necessary working

B.1d All workers must be wearing visible PPE

B.2 Generator (Diesel) equipment oil leakage during operation

B.2a Daily check of the equipment prior to start of work

B.2b Regular check &monitoring of the equipment prior to use

B.2c Provide sundry containment protection under the equipment to prevent contamination of soil by oil spillage

B.3 Oil/chemical storage B.3 Diesel/chemical shall be scored in sundry containment & MSDS requirement shall be communicated with all concerned

B.2b Regular check &monitoring of the equipment prior to use

B.2c Provide sundry containment protection under the equipment to prevent contamination of soil by oil spillage

C.1 Slip and trip of workers C.1 Secure confirmation by EHS manager regarding assigned engineers and workers

C.2 Fall of workers and equipment C.2 Excavation plan and excavation work checklist must be available at the work site C.3 Cave-in of excavation walls C.3a Assign licensed and experienced operator

Excavation sites must be secured with safety warning tapes or hard barricades marked in red and white, as applicable Additionally, it is essential to provide adequate lighting and blinker lights to ensure visibility during nighttime operations.

C.3c Install adequate safety signs such as excavation in-progress, keep-out deep excavation, etc

C.3e Assign experienced and trained personnel /workers

To prevent cave-ins or collapses, ensure that the spoil area is located at least 2 meters away from the edge of the excavation, especially if the excavated materials are not being immediately hauled or disposed of.

C.3g Provide sufficient shoring system, sloping of ground or other equivalent means such as sheeting, cross bracings, trench shield or box and jacks, benching, etc whichever is applicable

C.3h Prohibit movement of vehicles and equipment near the edge of the excavation that may result to side wall excavation cave in or collapse due to severe ground movement

D.1 Slip and trip of workers D1 Implement method statement / procedures on safe backfilling works

D.2 Fall of workers and tools /equipment

D.2a Strict supervision during backfilling works D.2b Wearing of the required PPE

D.2c Assign licensed and experienced operator

D.2d Assign experienced and trained personnel /workers

E Trenches E Falling from height and cave-in E.1 Earth excavated to be stored 2 meters away from excavation area

E.2 Vehicle to be kept in 2 meters from edge of excavation

E.3 Experienced and trained workers E.4 Essential PPE in use

F Extreme environmental condition such as high temperature

F.1 Implement safety procedures &guidelines on heat stress

F.2 Inspect excavation and adjacent areas for possible hazardous atmosphere and any other condition that may present a hazard

F.3 Suspend / stop all operations during extreme temperature & humidity and high wind

Engine) oil leakage during operation

G.1a Daily check of the equipment prior to start of work

G.1b Regular monitoring of the equipment sin order to control and prevent oil leakage and other engine trouble

G.1c Provide sundry containment protection under the equipment to prevent contamination of soil by oil spillage

G.2 Electric shock due to without ground external box on pump station and circuit breakers

G.2a Provide adequate ground and circuit breakers

G.2b Designate electrician/operator for the pump equipment

H Collision between equipment H.1 Prepare access for the equipment to be provided

I Dust Control I Vehicle/equipment transporting of excavated soil to the disposal

I.1 Spraying of water on the road as required to ensure no dust flying

ATTACHMENT

W = Pipe Unit weight * Length of Encasement = 13.81 (T)

PHASE 1:CAST CONCRETE TO 580mm height

Self-weigh of mass concrete Wmass= B*D*H*L=

PHASE 2:CAST CONCRETE TO +2.3M HEIGHT

Vs (m3) =R²/2*(απ/180-sinα)*L : Volume of CW pipe inside concrete

If calculation with pipe length equal encasement length, L=8m

W= 69.72 (T) Checking: if W>Fb: OK, conversely: Recheck

PHASE 3:CAST CONCRETE THE REST

Vs (m3) =R²/2*(απ/180-sinα)*L : Volume of CW pipe inside concrete

Self-weigh of mass concrete Wmass= B*D*H*L-0.5*3.14*R^2*D*L=

If calculation with pipe length equal encasement length, L=8m

W= 127.37 (T) Checking: if W>Fb: OK, conversely: Recheck

Checking the rebar as anchor

Capacity of tension for D16 T16=fy*F16

The quantity of rebar= 1.1*Wmass/T16= 16 nos

Space of rebar s=L/segment= 533.3333 mm

# ATTACHMENT2: Stability Check for Excavation Slope for CW Pipe near CW PS

This calculation is to check the slope stability for excavated slope Factor of satety of slope in excavation surface is examined by Bishop and Janbu method using SLOPE/W software

For the stability check on the excavation slope, limit equilibrium analysis was performed using the Slope/w program The Bishop and Janbu method whose reliability was verified in circular

& non-circular failure was applied

Direction of the resultant interslice force is paralled to the base of the slice The balance of vertical force for the base of the slice was considered

Interslice shear force is zero The balance of vertical force the base of the slice was considered

Janbu Location of interslice normal force is defined by an assumed line of thrust

Excavation and sections for stability check are:

No Area Excavation Depth Ground Level

1 CW Pipe nerar CW Pump Station Area EL.+0.5 EL.+5.6

Soil property for soil layer(BH-42) is refered from Soil investigation report (Ref VP1-0-L4-C- GEN-00001)

(kN/m3) Cohesion (kPa) Friction angle

5 SAFETY FACTORS FOR SOLPE STABILITY

The required safety factors for stability performance is summarized in following

Tide level in Excavation area for the design is as following

- Ground Water Level : EL+0.07m (Ref VP1-0-L4-C-GEN-00001)

7 SECTION FOR SLOPE STABILITY ANALYSIS

* 13kN/m2 of surcharge load was considered on the ground level

Tiêu đề	Method Statement For CW Pipe Line Civil Work
Thể loại	For Approval
Năm xuất bản	2020

Định dạng
Số trang	65
Dung lượng	5,72 MB