1.0 INTRODUCTION
WPC Office complex is a
sixteen storied building with a total floor area of about 40,000 sqm including the basement parking area, twelve
office floors and council chamber on the 13th floor
level
As per the architectural design, structural
elements are slightly different than the each and other floors to facilitate the
different types of MEP services as required for the floor arrangements.
Therefore, we use a conventional formwork system with necessary modifications as
required at the different floor levels.
2.0
REFERENCES
- Structural
Construction Drawings
- Inspection
sheet for structural work
- Form
work method statement
- Trial
Mix Reports/ Admixture Reports
3.0
RESOURCES
3.1.
Material
1.
Timber – 50 x 50 , 100 x 100 mm
2.
15 mm thick. Plywood sheets
3.
Form ties and pre cones
4.
GI Pipes / acro jacks – For support
5.
Ordinary Portland Cement
6.
Aggregates
7.
Sand
8.
Water
9.
Admixtures
10.
Water Bars
11.
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/Mammoth
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
16.
Compressor
3.3.
Man Power
1. In charge Engineer (Structural) – 01 no
2.
Concrete In-charge Engineer – 01 no
3.
Assistant Engineer – 02 nos
4.
Construction Supervisor – 01 no
5.
Survey Helper- 01 no
6.
Concrete Forman – 01 no
7.
Masons – according to the requirement at that time
8.
Skilled Workers - according to the requirement at that time
9.
Unskilled Workers- according to the requirement at that time
10.
Standby Carpenter - according to the requirement on that time
11.
Standby MEP Service Workers -according to the requirement on that time
12.
Machine Operators - according to the requirement at that time
13
.QA/QC Engineer – 01 no
4.0 Form Work
This
is a major activity that bears the weight of concrete until it gets the required
strength. So it is essential to take care of the correct methodology for fixing
and supporting.
4.1 Type of formwork
·
Sides
of Beams and columns
·
Soffit
of slab and beams
·
Stair
case formwork
4.2. Formwork
Arrangement –Columns and Slabs
4.2.1 Formwork Arrangement – Columns
- Plywood (15mm
thick) will be used for smooth finishing surfaces
- Formwork
arrangement for columns is shown in drawing no. 1
- Setting out
carry out according to approved structural or setting out drawing.
- Verticality of
the column formwork will be checked using four plumbs at two nos. on each surface.
- 200 mm off
lines are marked on floor concrete to check the position of the column.
4.2. 2 Formwork Arrangement – slab and beams
- Plywood sheets
(15mm thick) will be used for smooth finishing surfaces.
- Plywood sheets
shall be laid on GI pipes (distance between two pipes 200 mm), which are
on the 4”x4” timber blocks, with a distance of 600mm.
- Beam soffit
will be supported by acro jacks
- Slab soffit
will be supported with acro jacks by using 4”x 4” timber planks and U
jacks.
- Beam bottoms shall be supported on
pipe supports and T – jacks, which are held on the below slab.
- All joints
will be covered with appropriate sticking tapes
- Mineral mold the oil will be applied before
concreting
- Formwork arrangement
for slab and beams are shown in drawing no. 2
- Before doing the
concrete, the slab shall be
leveled with the leveling instruments
4.3 Construction
Joints
Slab
and beams may be temporally stopped keeping continuation further and called
construction joint. The way is to depend upon structural definition keys will be provided
as required on specifications shown in the sketch. Beam vertical construction joint
keeps 1/3 or 2/3 of concrete beam span. As the Structure is divided into zones,
construction joints shall be formed, when doing part concreting. Details of the
typical construction joints for a slab are shown in Fig 4.
Stair
Case Formwork (Conventional Formwork)
Staircase formwork shall
be carried out in the same way of doing horizontal formwork. Arrangement of a
slopping formwork is shown in below Fig. 3
Note: Staircase concreting will
be done only after completion of the slab concrete. (i.e. starting floor &
the landing floor within one-floor height)
4.4 Cleaning of
formwork
- Surfaces will be well cleaned of all
dirt and dust by using 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,
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
4.9.1 Column form work
Surveyor
helper marked setting out lines on slab. Before erect column form work marking
lines are check by Engineer or related officer. After erecting the column form
works again verticality check. After complete the concrete pouring supervisor
will be check verticality of form work and cleaning of surround area.
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.
6.8 Compaction of concrete
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.
|
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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