TABLE
OF CONTENTS
1.0
INTRODUCTION
2.0 REFERENCES
3.0 RESOURCES
4.0 FORM WORK
5.0 RAINFORCEMENT WORK
6.0 CONCRETE WORK
7.0 RESPONSIBILITIES
8.0
QUALITY ASSURANCE / INSPECTIONS AND TESTING
9.0
SITE ARRANGEMENTS
10.0 SAFETY PLAN
METHOD STATEMENT FOR PILE
CAP AND TIE BEAM CONCRETING
1.0
INTRODUCTION
·
WPC Office complex is a sixteen storied
building with total floor area of about 40,000sq.m including basement parking
area, eleven no’s of office floors and council chamber at the 13thfloor
level. It has been designed for bored pile and bulking pile cap foundations as
well. This Method statement describes the way of doing concrete casting for Pile
caps, Tie beams and Perimeter walls. Quality Assurance and Quality controlling
plan also enclosed in the method statement.
2.0
REFERENCES
- Structural
Construction Drawings
- Waterproofing
Method statement - to be submit
separately
- Termite
treatment Method statement - to be submit separately
- Inspection
sheet for structural work
- Form
work method statement
- Trial
Mix Reports/ Admixture Reports
3.0
RESOURCES
3.1.
Material
1.
Cement Blocks (200 mm thk. Solid )
2.
Timber – 50 x 50 , 100 x 50 mm
3.
12 mm thk. Ply wood sheets
4.
Form ties and pre cones
5.
GI Pipes / acro jacks – For support
6.
Ordinary Portland Cement
7.
Aggregates
8.
Sand
9.
Water
10.
Admixtures
11.
Water Bars
12.
Ready mix Concrete ( as per approved mix
design )
The
mix proportions are designed by mix design and verified by Trial mix and trial
workability tests.
1.
Batching plants
2.
Truck Mixers
3.
Stationary Concrete Pump with Lines/ Pump
Cars
4.
Concrete Distributor
5.
Shovel/Mammoty
6.
Porker/Shutter Vibrator
7.
Level Bar
8.
Level Machine with staff
9.
Concrete Chute
10.
Tower Crane with Bucket
11.
Mason Trowel
12.
Wooden Float
13.
Plumb bob
14.
Water pressure gun m/c
15.
wire brush
3.3.
Man Power
1. In charge Engineer (Structural) – 01 no
2.
Concrete In charge Engineer – 01 no
3.
Assistant Engineer – 01 no
4.
Construction Supervisor – 01 no
5.
Survey Helper- 01 no
6.
Concrete Forman – 01 no
7.
Masons – according to requirement on that time
8.
Skilled Workers - according to requirement on that time
9.
Unskilled Workers- according to requirement on that time
10.
Standby Carpenter - according to requirement on that time
11.
Standby MEP Service Workers -according to requirement on that time
12.
Machine Operators - according to requirement on that time
13
.QA/QC Engineer – 01 no
4.0 Form Work
This
is a major activity which bare the weight of concrete till it get the required
strength. So it is essential to take care of the correct methodology for fixing
and supporting.
4.1 Type of form work
·
Sides
of Pile caps
·
Sides
of Beams
·
Perimeter
Walls
4.2 Preparation of
formwork
Pile cap and
tie beam area floor leveled and compacted as per the correct required levels . after that screed concrete lay
accordingly to requirement .
4.2.1 Formwork
Arrangement –Pile caps and Tie beams
- Before start the pile cap
setting out we get approval for as built drawing for pile layout from
consultant.
- After laying screed
concrete we are doing the setting
out work for pile caps and tie
beams . Then start the pile caps and tie beams form work
- 200 mm thk. Solid cement blocks used
as a form work for pile caps and tie beams
- Verticality of block walls will be checked using plumbs
- Sketch 1 and Sketch 2 is attached for
reference. Its show supporting system for pile caps and tie beams
- Shoring work beams, wales and ties details
and design calculations are submit with shoring and dewatering method
statement
4.2.2 Formwork
Arrangement – Perimeter walls
- Marine plywood
(12mm thick) will be used for smooth finishing surfaces
- 50 mm height
kickers will be casted after locating position
- Verticality of
the mould will be checked using plumbs on each surface
- Sketch 3 is
shown supporting system for walls
4.3 Construction
Joints
Tie beams may be temporally stopped keeping continuation further and
called construction joint. The way is depend upon structural definition keys
will be provided as required on specifications and Pile cap construction joint
shows in sketch 1and sketch 2 .Tie beam vertical construction joint keep 1/3 or
2/3 of concrete beam span .
4.4 Cleaning of
formwork
- Surfaces will be well cleaned of all
dirt with compressor or water pressure m/c
4.5 Removal of Formwork
All
formwork should be removed without damage on concrete. The form of supports
would not be struck until the concrete has reached the sufficient strength. Form
work may be removed after the time as shown in the following,
Cement
Block form work keep as it is after done the concrete
Form work removing done according to
Table 2.2 in specification if we concrete without admixtures or refer table 5.3 at ICTAD Building works volume 1 .
4.6 Stacking of removed formwork
- Removed panels
will be stored at safe covered place
- All panels
will be installed vertically
4.8 Check List
- Marking lines
- Alignment of
vertical form work
- Levels of
horizontal formwork
- Supports
- Dimensions
- Joints of
panels
- Cleaning of
form work
4.9 Quality Controlled measures
Engineer
or Ass. Engineer re check marked lines. First block wall lying is check by Engineer
or related officer. After finished the block work again verticality check. In
between time period supervisor will be check verticality of form work and
neatness of block wall. After finished the form work supporting systems and
dimensions are recheck before start the re bar work.
5.0 Re bar Work
- Mill reports and
test reports for steel will be submitted to the consultant before
execution of work
- Re bar
schedules will be prepared by an Engineer
- Cutting and
bending will be done at site or bar bending yard accordingly bar schedule.
- All laps,
joints and anchorage will be kept to the standard given in drawing by
consultant
5.1 Equipment’s
- Bar bending
machine
- Bar cutting
machine
- Chop saw m/c
5.2 Reinforcement
steel placing
- All steel bars
will be cleaned before placing
- Cover blocks
will be used to maintain the adequate cover to reinforcement
- Chairs or
Stools will be used to maintain the gap between top and bottom bars
5.3 Cover to
reinforcement
Cover to reinforcement will be follow
as per structural drawing and related site instructions .
Minimum
lap length as specified by consultant
5.5 Check List of
Re bar
- Steel sizes, spacing
and position
- Steel tying
and binding
- Lap length,
anchorage length
- Covering
- Chairs or
stools between top and bottom net
- Cleanliness,
If
any MEP work related to pile cap , place
and confirm prior to concrete works .
6.0
CONCRETE WORK
6.1 Materials
- All concrete grades will be used as specified in drawings and
Consultants
6.2 Concrete
Used
- Site Mixed ( get prior approval from Consultant )
Using concrete mixtures
done by manually at site for G15
- Batching Plant Mixed
Concrete batching plants
Mix Designs approval gets from consultant
6.3
Transportation of concrete
- Concrete will be transported to the site by truck mixers from
batching plant
- Site mixed concrete done by at site for G15 ( using gage boxes and
necessary inspection to check quality )
6.4 Placement
of Concrete
- Consultant will be informed at least 12 hours before approval
required
- If needed we used a pump car or Tower crane to pump concrete.
- As level increases, permanent pipe lines will be installed to pump
concrete
- After the approval of consultant for reinforcement and form work,
concreting will be done with all necessary equipment
- Chute will be used where
required keeping slopes not to cause segregation
- Poker vibrators shall be used to compact the concrete well
6.5 Leveling
of Concrete
- Height gauges will be used to maintain the correct levels
- Concrete finish level will be marked at Column reinforcement to
control the pouring on pile caps
- Concrete finish level will be checked after concreting using
leveling instrument
- If necessary string is used to checked level of concrete
6.6 Pile Cap
Concreting
- Dust
and debris, which exist inside the formwork, shall be blowered and cleaned
well, prior to commence the concreting. Cavities if there are any, shall
be sealed to avoid grout leakages. Pile cap shall be concreted by using
the mobile or stationery concrete pump and distributors. Concrete shall be
poured in to the pile cap.
- Proper
compaction shall be done by using poker vibrators. Level of the pile cap and
the surface finish shall be maintained while doing the concreting. A
careful attention shall be paid to ensure whether the conduits and other
service lines are not damaged (if embedded); and if there are damages in
service lines, it shall be informed to the relevant sub-contractor. If
somewhere concrete not segregation in significant that concrete part
remove .
6.7 Large
scaled Pile Cap Concreting
The large scaled
element, which the depth is higher than 1000mm,shall be concreted strip wise,
as shown in the follow and the thickness
of concrete layers shall not be exceeded 1000mm. By doing this way, it can be
laid the concrete, over the previously concreted layer before it is getting
set.
After
pouring one layer, the compaction of about 25sec to 30sec, shall be done by
inserting vibrator based on the marks. The vibrator needle should not disturb
previously concreted layers. Vibrator inserted in 1m intervals of above
intervals .
6.9
Testing related to the Concrete work
- Slump will be checked for each truck mixer and record with
consultant representative
- 150mmx150mmx150mm test cubes will be produced for compressive
strength checks for 7 days and 28 days
- Test cubes will be checked in NBRO or related Lab
6.10 Curing
of concrete
- Curing shall be started as soon as
possible and practical after placement of concrete
- The concrete shall be covered with a
layer of sand and kept constantly
wet for a period of 7 days
6.11 Green Removing
Removing of the grout, wire brushing of the
construction joints or cleaning with water pressure gun shall be carried out
within the concrete is in the fresh state.
6.13
Check List
- Form work
- Reinforcement
- Supports
- Manpower
- Machinery and equipment arrangement
- Sample testing
7.0. RESPONSIBILITIES
|
Position
|
Responsibility
|
|
Engineer in charge (structural)
|
1. Get
approved for Concreting (i.e. for R/F,
F/W and for Services)
2. Cleaning
of debris in the form work.
3. Sealing
the joints of formwork to avoid the grout leaks.
4. Arranging
all infrastructures for Concreting.
5. Curing
of Concreted elements.
|
|
Concrete In charge
Engineer
|
1. Estimating
the required Concrete volume and order from the batching plant.
2. Testing
and Sampling the Concrete.
3. Keeping
records of concreting.
4. Handling
the traffic of the Concrete truck mixers.
5. Quality
controlling of Concreting.
|
|
Assistant Engineer
|
Assist
to the Tower Incharge.
|
|
Construction Supervisor
|
1. Assist
to the Concrete Incharge.
2. Handling
the Concrete gang.
|
|
Concrete Forman
|
Handling
the Concrete gang.
|
|
Survey Helper
|
Maintaining
the verticality and required levels of the concrete elements.
|
|
Admin Officer
|
Providing
the welfare facilities for Concreting staff and for workers.
|
|
Safety Officer
|
Marinating
Safety and Health in the working area.
|
8.0. QUALITY ASSURANCE / INSPECTIONS
AND TESTING
8.1
Material
Slump
Value : Specified slump value +/- 25 mm
Grades
of Concrete: 30N/mm2 for Piles
40N/mm2 for
Pile caps
8.2 Concrete Sampling
& Testing Plan
Samples shall be taken for cube crushing
test as follow by specification or consultant instruction:
8.3
Inspection for Construction
All
kinds of inspection for construction shall be carried out by the site Engineers
along with Engineers representative and QAQC Engineer of SANKEN as per the
standards and specifications.
However,
prior information shall be given to Consultant representative at site to
proceed necessary checking’s periodically & make final comments.
Inspection
shall be carried out while progressing of the work & approval shall be
granted without affecting to the progress of the work.
Following
Forms are used for the above quality maintaining works.
1)
Quality Check Lists and Approval Sheets For
Structural Work
2)
MEP Inspection sheets if available
9.0 SITE ARRANGEMENT
Site Infrastructure
Arrangement plan is attached as annexure.
10.0
SAFETY
PLAN
·
All the dangerous areas must be barricaded
·
Safe flat forms for working at higher
levels shall be provided.
·
Safety Guard rails shall be provided at the
perimeter run.
·
All the electrical wires and sockets such a
way that must be covered to safety regulations
·
Very good site illumination will be
provided, if concrete pouring continues to the night time.
·
Water pumps must be ready at any time for
immediate use.
·
First aid facilities and vehicles for
emergency cases shall be available at site.
Refer
the Sanken Lanka Safety Manual for other safety precaution and regulations.
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