METHODE WORK
STATEMENT
Backwash Water Collecting Basin
1. SCOPE
This Method Statement document is a general requirement for Routine Daily Maintenace work in the PT. Hastakarya Tunggal Mandiri. To be precise in the SMI Plant. This work will be constructed by PT. Hastakarya Tunggal Mandiri.as a Sub Contractor and PT. Chandra Asri Petrochemical as a Supervise.
2. RESPONSIBILITY 2.1 Project Manager
a. Identify work method to be employed
b. Prepare construction schedule, manpower schedule and equipment schedule c. Make planning regard in the work to be implemented
d. Coordinate and interface with related parties
2.2 QA/QC Engineer
a. Prepare Work Method Statement b. Make materials approval
c. Monitor and inspect during construction activities
2.3 Supervisor
a. Prepare equipment and tools needed for the work
b. Conduct daily tool box meeting to regulation remind / educate the working crew regarding hazard identification of this particular work with their corresponding control
c. Responsible for monitor construction activities, it is done in compliance with this procedure and specification.
2.4 HSE Supervisor
d. Assess risk base on the risk identification
e. Assess the work determine compliance with HSE regulation and procedure.
f. Ensure timely preparation, submittal and / or maintenance of required HSE record keeping document such us ; inspection report, training record, equipment log, TBM record, etc.
g. Supervise activity related to HSE matter
2.5 Logistic
a. Distribution tools and materials b. Monitoring warehouse
3. WORK SEQUENCE
3.1 Preparatory Main Material a. Plywood 12-18 mm thk.
b. Concrete Dry Mix, Ex. Decon Dry Mix DC 300 or equiv.
c. Reinforcement Bar BJTD 40, Ex. Delco Prima, Master Steel, IWS or equiv.
d. Viscocrete, Ex. Sika Viscocrete 3115N e. Waterstop Bar V25, Ex. Sika Waterbar f. Bonding Agent, Ex. Sikabond NV g. HDP Step Ladder D19 @ 250 h. Polyurethane RAL 7001, Ex. Miswax
i. Epoxy Waterproofing 300-500 mic. Colour : Light Grey, Ex. Nitocote EN. 901 3.2 Tools and Equipments
a. Vibrator Machine b. Diesel Concrete Mixer c. Cement Slince
d. Wire e. Nail f. Hammer g. Saw
h. Waterpass i. Excavator PC 75
3.3 Pre-Execution Activities
a. Prepare Work Method Statement
b. Submit Job Hazard Analysis, and conduct meeting with CAP c. Apply Permit to Work to obtain permission excecution work d. Prepare Materials, Equipments and Tools
e. Prepare safety signs
f. Conduct safety training (induction) for all personnel in-charge
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4. WORK SEQUENCE
Picture 1. Section Basin
Picture 2. Layout Basin
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NO Activities Detail Activities
General Activity
1 Survey Marking and Plot
2 Trial Digging 1 Joint survey with CAP 2 Trial digging
3 Provide safety sign & baricade work area (if needed)
3 Excavation &
Compaction Subgrade
1. Excavation using Excavator
2. Joint Survey with CAP for check Elevation 3. Dispose soil to CAP reference area
4. Delivery Subgrade Material (Basecourse A) 5. Compaction Subgrade (with Compactor) until
90 % Max Dry Density
6. MDD Inspection (if Failed, back to compaction until 90%)
4 New Basin Backwash Water Collecting
1. Lean Concrete 1. Install PE Sheet
2. Pouring dry mix concrete min fc’ 100 kg/cm2 2. Ground Slab 1. Install rebar for slab & wall, size, length &
distance refer to drawing.
2. Install formwork using Plywood as per spec req.
3. Install water stop
4. Mixing concrete dry mix K-300 with viscocrete
5. Check slump (standar refer to spec)
6. Pouring concrete & compact using vibrator 7. Curing
3. Wall 1. Cleaning rebar
2. Install formwork using Plywood
3. Install ladder & support the ladder position using wire & rebar
4. Mixing concrete dry mix K-300 with viscocrete
5. Check slump (standar refer to spec) 6. Apply bonding agent
7. Pouring concrete & compact using vibrator 8. Curing
5 Back Filling 1. Finishing & conduct final visual inspection 2. Apply PU to the concrete above ground 3. Backfilling area using import soil untill design
elevation.
4. Compacting using compactor
8 Handover 1. Leak test
2. Final measurement
1. DETAIL WORK SEQUENCE
a. Survey Work
Before all activities conducted, construction area will be marked by Hastakarya Team and witnessed by CAP in charge. Then determine the point by the survey team according to the location of the SMI Plant that had been shown on engineering drawing and to provide min. 2 benchmark local or masterpiece of survey point . Make sure auto level and total station already calibrated. Construction area shall be barricaded by hard barricade
b. Trial Digging
Before start excavation works, trial digging is describes excavation soil as trial digging by manual using conventional tools. trial digging is useful to know whether it's safe or not from the existing underground piping
a) Surveying Work
Excavation area marked by Hastakarya’s surveyor, coordinates and elevation. HASTAKARYA will do joint survey with CAP’s surveyor prior excavation activities conducted. Benchmark and level point references based on SMI Plant’s benchmark location.
b) Area Clearance
Area clearance here is an activity to ensure that excavation work do not damage any existing CAP’s facilities up ground. Facilities damage should be avoided and relocation CAP’s existing facilities should be done should be ordered by CAP.
c) Soil Excavation
Excavation of soil should be based on latest drawing from CAP, or if any change of excavation should be ordered by CAP. Excavated soil will placed near the excavation area, excavated soil will re-use for back filling.
d) Back Filling
Back filling activities here is describes put whole soil back, which placed near excavation area into excavated hole only.
c. Excavation
a) Excavation of soil should be based on latest drawing from CAP, or if any change of excavation should be ordered by CAP. Excavation will using excavator and it will excavate soil and / or rock outside excavation
b) Excavation shall be carried out the depth as shown on the drawing without disturbing the ground to be left in natural condition
c) Hard barricade and proper stair and ladder shall be installed around excavation area
d) After Excavation and unused land immediately discarded with the disposal truck and provide man power to clean up road along disposal truck
e) If the 1.2 meter excavation depth will be made 1: 1 slope on the upper side, if it is not possible it will be protected by shoring using scaffolding material
f) After excavation After excavation 1,2 meter do it gas test periodically d. Subgrade Compaction Work
a) Survey and marking area for Subgrade b) Compaction with Compactor (Stamper)
c) Inspection with CBR test every 200m², 90% relative dry density as per ASTM D1556 at site with reference laboratory test as ASTM D1556
d) Continue to be repeated over and over until the required level needs are obtained
e) Joint Survey for Elevation before rebar installation.
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e. Lean Concrete
Make sure soil on the bottom of lean concrete already compacted or compressed with Basecourse A, installing lean concrete form work, than give a mark for elevation top of lean concrete. Conducting pouring concrete after inspection approved. Before casting, make sure to proceed slump test according to concrete slump specification. Using concrete with minimum strength fc’ 100 kg/cm2
f. Form work slab
a) Formwork for slab will use Ply wood and Hollow comply spec.
b) Formwork shall be constructed to conform to shape, lines, dimensions and details as indicated on the drawings and shall be sufficiently rigid to prevent deformation under load.
c) Formwork for exposed surfaced shall be coated with oil before reinforcement is placed
d) Formwork shall not be remove until concrete has attained sufficient strength to support its own weight and any superimposed loads g. Reinforcement Bar Work slab
a) All materials shall be free from rust, grease or any other coating which would reduce the bond to concrete
b) Install waterstop bar using cold joint method. Flatten and rough two joints, and then apply a thin layer of sealant. Apply another layer of sealant after drying. Place two joints in a predetermined position after drying for adhesion and pressurization.
c) Install Rebar For slab Until Vertical Wall
d) All cutting and bending shall be done in accordance the bar bending schedules, welding of cross bars shall not be permitted.
e) Concrete spacer blocks, bar chair or the equivalent material shall be use to avoid deflection more over, spacer tied of form work must be rigid enough to hold it self during pouring concrete work.
f) Moreover, spacer tied to the lateral side of form work must be rigid enough to hold it self during pouring concrete work
h. Concrete Work for slab
a) Clean the area to be pouring with a compressor or manually b) Preparation access and area for portable mixer
c) Mixing concrete dry mix & viscocrete using portable mixer & check slump
d) Pouring concrete and compacted using vibrator e) Finishing exposed concrete & curing
i. Dismantling Formwork
a) Formwork manhole and foam for block out dismantling refer construction procedure
b) If joint visual inspection after formwork removal, regardless the defect category, HASTAKARYA shall not repair or even minor patching the defect without following steps/procedure
c) Report to CAP for detail Inspection
d) Repair will be carried out after CAP approval j. Reinforcement For Wall & Ladder Installation
a) All materials shall be free from rust, grease or any other coating which would reduce the bond to concrete
b) Install Rebar For horizontal wall
c) All cutting and bending shall be done in accordance the bar bending schedules, welding of cross bars shall not be permitted.
d) Concrete spacer blocks, bar chair or the equivalent material shall be used to avoid deflection moreover, spacer tied of form work must be rigid enough to hold it self during pouring concrete work.
e) Moreover, spacer tied to the lateral side of form work must be rigid enough to hold it self during pouring concrete work
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f) Install ladder as per spesification, support using wire and rebar and make sure ladder position already correct.
k. Formwork for wall
a) Formwork for slab will use Ply wood
b) Formwork shall be constructed to conform to shape, lines, dimensions and details as indicated on the drawings and shall be sufficiently rigid to prevent deformation under load.
c) Formwork for exposed surfaced shall be coated with oil before reinforcement is placed
d) Formwork shall not be remove until concrete has attained sufficient strength to support its own weight and any superimposed loads e) Fabrication form work activity at site
f) Provide for sparing or block out for ladder l. Concrete work for wall
a) Clean the area to be pouring with a compressor or manually b) Preparation access and area for portable mixer
c) Mixing concrete dry mix & viscocrete using portable mixer & check slump
d) Pouring concrete and compacted using vibrator
e) During pouring concrete give “SIKA bond nv” for joint concrete / Cold Joint Treatment
f) Finishing exposed concrete & curing m. Curing & Finishing Method
a) The concrete surfaces must be clean and free grease and old concrete
b) The concrete surface that are not in contact with the formwork shall be kept continuously moist for 7 days by covered with burlap or spray water immediately after finishing the surface
c) The covering material ( burlaps ) shall remain in place during the full curing period.
d) Apply PU to the concrete above ground e) Conduct final visual inspection with CAP n. Backfilling
After installation completed, we need to backfill area with import soil (if needed) until design elevation. Compact and conduct density test (Sandcone Test).
5. SAFETY PRECAUTION
a. Make sure that necessary documentation prior to work are approved by Client b. Ensure that the risks of the work to be performed prior to start have been
assessed and the countermeasure have been determined. Make that JOHAN are cascaded to the workers and clearly understood before the work starts.
c. Make sure that Tool Box Meeting in the working place is conducted before starting the work
d. Ensure that all workers are wearing proper PPE when entering area
e. Make sure that all tools & equipments are checked prior to use and regular routine checking shall be done
f. Ensure that no person shall be permitted to enter on the lifting area g. Ensure working permit has approved before starting the work h. Ensure that all workers are implement the Covid-19 Protocol
