Method Statement of Slab on grade

CÔNG TY CỔ PHẦN XÂY LẮP THƯƠNG MẠI 2
Architects & Construction Service Corporation

METHOD STATEMENT
SMC Manufacturing (Viet nam) Factory-Phase 1 Project

RC SLAB ON GRADE
FACTORY 1

Ref No:
SMC-ACS-MS-01-CCW-004 Rev 02

ACSC- CONG TY CO PHAN XAY LAP THUONG MAI 2

SMC-Factory No.1/MS-Slab On Grade

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Revision History
Revision
01
02

Date of issue
02/12/2015
30/12/2015

Purpose of issue (approved/ revision)
For Review
Revised as per KOA comments

Submitted by ACSC
Prepared by
Reviewed by
Approved by

Name
Lê Long Hậu
Nguyễn Hoàng Trinh
Nguyễn Văn Trung

Position
Deputy Site Manager
Site Manager
Project Manager

Date

Signature

Approved by KOA
Checked by
QA-QC
QA-QC
HSE
KDA

Position

Date

Signature

Date

Signature

Reviewed by
Approved by

Approved by Client Name
Prepared by
Reviewed by

SMC-Factory No.1/MS-Slab On Grade

Position

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Contents

SMC-Factory No.1/MS-Slab On Grade

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1. INTRODUCTION
1.1. GENERAL
This document describes the procedures and method for carrying out the construction works for Slab on
Grade of building factory No.1. This method statement will be applied after completion of the RC
structures such as foundations, ground beams, columns and the works of soil stabilization and lean
concrete on the ground. The constructions of those work items were carried out by previous stage;
therefore they will no longer discuss in this method statement.

1.2.

DEFINITIONS:
PROJECT PARTICULARS:
Project name

: SMC MANUFACTURING (VIET NAM) FACTORY-PHASE 1 PROJECT

Address

: Long Duc Industrial Park, Long Duc Ward, Long Thanh District, Dong Nai Province,
Viet Nam.

PARTY:
Client/ Owner : SMC MANUFACTURING VIETNAM CO., LTD

Contractor

: KAJIMA OVERSEAS ASEA PTE LTD.
Responsible for the supervision of Contractors who will construct the podium and all
related activities as outlined in this procedure.

SCOPE OF WORK
The works to be carried out by Sub-Contractor (ACSC) and shall apply for works at Factory No.1 of SMC
MANUFACTURING (VIET NAM) FACTORY- PHASE 1 PROJECT.
1. Construction Reinforcement Concrete Structure works included:
a. Pile head treatment
b. Earth work
c. Formwork
d. Reinforcement Steel Rebar work.
e. Concrete work
2. Finishing works included:
a. Brick work
b. Plaster work.
c. Painting work
d. Tiling work (Wall & Floor)

2. BUILDING DESCRIPTION:
Location:
Factory No.1 are located at the corner of Road No.D5 &N2-5 in Long Duc Industrial park as below

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Factory No. 1
Description:
•
•
•
•

Building purpose : Factory
Foundation
: Spun piles (D300, 350, 400 mm)
Structure
: RC structures + steel rafter; Slab on grade.
Dimensions:
o Factory
 140m long (14x10m); 60 (4x15m) - 69m wide
 Ground Floor (FL. 0.00m); 1st Floor (FL. +7.25m)
 Height : 11.40m
o Utilities area: 2 x (120m long, 4.5m wide).

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GROUND FLOOR PLAN

•

Floor load:
o Factory Ground Floor
o WC Ground Floor
o Stair case
o Storage/Utilities

•

Slab thickness:
o Factory Ground floor slab
: 300 mm thk.
o Storage/Utilities Ground Floor slab : 150 mm thk.
o 1st Floor slab
: 140 mm thk.

•

Area:
o

o

: 40 KN/m2.
: 2 KN/m2.
: 3 KN/m2
: 10 KN/m2

Ground floor
+ Factory area
+ Storage/Utilities area
1st Floor

SMC-Factory No.1/MS-Slab On Grade

: 9561 m2
: 8400 m2
: 1161 m2
: 9561 m2

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COR RID OR Z INC ROOF SHEET

C OR RI D O R Z IN C R OO F S H E E T

9500
4800

4 800

T .O .BEAM
G FL+11.900

4 650

F A C T O R Y -02

1FL
G FL+7.250

7 250

C O N NE C T IO N
C O R RI DO R

11600

LOA DING B AY

T .R.B EAM
G FL+13.650
1 750

1/ 2 0

1/ 20

S TE EL K ICK ER
CAN OP Y; S TE EL B EAM

1 3650

G UTTER
DOW N SPOUT

GFL
G FL±0

G UA RD P OS T ( 100?, H=1500)
4500

1 5000

15000

1 5000

15000

4500

1 2000

60000

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TYPICAL CROSS SECTION

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3. ORGANIZATION CHART
3.1. Organization Chart (Factory No.1)
Project Manager
NGUYỄN VĂN TRUNG (MP: 090 330 7742)


Site Manager
NGUYỄN HOÀNG TRINH (MP: 090 2911235)


Deputy Site Manager 1

Deputy Site Manager 2

NGUYỄN TRÍ KHOA (MP: 0937 229 680)

LÊ LONG HẬU (MP: 093 734 3055)

Site Engineers

QA&QC

Nguyễn Minh Tuấn (MP: 098 314 5069)

Phan Quốc Trường (MP: 0906 027 797)

Nguyễn Văn Hào (MP: 0938.722.730)



Shop Drawings
Safety Supervisors

Hoàng Văn Hải (MP:908 818 1059)

Đỗ Vũ Quyền Anh (MP:090 853 1908)

Construction teams
Phương Phương Việt Company

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3.2. Assignment
Position
Deputy Site manager
Site Engineer
QA&QC Engineer
Safety Supervision

Factory No.1
NGUYỄN TRÍ KHOA

Factory No.9
TRẦN AN TOÀN

NGUYỄN MINH TUẤN
NGUYỄN VĂN HÀO
PHAN QUỐC TRƯỜNG
ĐỖ VŨ QUYỀN ANH

LÊ VĂN TUẤT
BÙI CÔNG HUYNH
BÙI THANH HẢI
PHẠM VĂN MẠNH

4. SCHEDULE
Construction Schedule of 1FL beams/slab is attached in Appendix-2.

5. SPECIFIC STANDARD
Reinforced Concrete Beams/slab shall be carried out in accordance with the requirements of:

•
•

•

SMC MANUFACTURING (VIET NAM) FACTORY-PHASE 1 PROJECT Specification for beam/slab
works.
Current Vietnamese Construction Standards.
+ TCVN 5593 : 1991 Vietnamese standard 5593-1991 (Building engineering work - Permissible
tolerances in geometry)
+ TCVN 1651-2008 Vietnamese standard 1651-2008 ( Steel for the reinforcement concrete,
part1+2)
+ TCVN 4453 – 1995 Vietnamese standard 4453-1995 (Concrete structures- codes for
construction, check and acceptance)
+ TCXDVN 371 - 2006 Vietnamese standard 371-2006 (Acceptance of constructional quality of
building works).
Related Materials approved by KAJIMA & Owner.

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6. SCOPE OF WORKS:
The Slab on Grade in factory No.1 include main area 140m long x 60m (8400 m 2) wide and the sub-area along
grid A & E (120 m long x 4.50 m wide, 1080 m2).
•

The designed load capacities of Slabs are classified as below:
Area
Factory
WC
Stair case
Storage/Utilities

•
•
•

Live Loads (kN/m2)
40
03
03
10

The thickness of slab mostly is 300 mm for Factory area. The areas with 150m thick slab are
mostly in Storage/Utilities area.
The level of slab mostly is +0.00 (m), except the areas of Utilities which will vary from -0.03 to
-0.15 m (in compared with GFL).
All slab areas are level except the corridor areas will be sloped outward.

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7. FLOW CHART AND DIRECTION OF WORK
The work sequence of construction the Slab on grade is shown at the following flow chart.

Soil stabilization
Previous stage
Casting lean concrete of ground slab

Surface preparation

Formwork fabrication

Installation formwork

Laying PVC sheets

Installing wire mesh

Rebar fabrication

Installing reinforcement

Casting concrete

Surface Finishing

Cutting joints

Curing concrete

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8. PREPARATION WORKS
•

Surface preparation
+ Check the finished level of lean concrete. Establish as-built drawings.
+ Chip out and remove all debris, loose material on top surface of s.
+ Cleaning the surface on the top of with water.
+ Cleaning any laitance, dirt, dust on the starter bars.

•

Pre-fabricate formwork
+ Plywood are cut in compliance with design width.
+ The reinforced steel boxes 4x8 (cm) are fixing to plywood to result the formwork panels.
+ The formwork panels will be transported to site near the construction area.
+ To ensure the fair-face formwork, the plywood will be used with maximum 4 cycles.

•

Pre-Fabricate Steel rebar
+ Obtain approved shop drawings and Bar Bending Schedule.

+ Manufacturing steel rebar.
+ Casting concrete block for spacer.
+ Deliver steel rebar to site and stock near construction area.
+ Install the starter bars of Ground slab, if any.

+ Concrete blocks will be used as spacer for side in order to keep the appropriate
concrete covering. Spacers will be pre-made with fine aggregate concrete, grade B20. They are
shaped by casting in PVC mould D42- D49 (mm). Their heights are depended on the thickness of
concrete cover (4cm) determined in Technical Specification for each kind of structures. The
concrete proportion is proposed for one mix as below:
Cement
Sand
Fine stone (dmax=10mm)
Water

•

: 50 kg
: 49 liter
: 99 liter
: 22.8 liter

Concrete work
+ Cover the RC structures can be affected during casting concrete.
+ Prepare the location for concrete pump.
+ Order the concrete.

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9. CONSTRUCTION METHOD
9.1. Casting schedule:
The casting concrete of Slab On Grade will be divided into two zones:
Zone 2

Zone 1

Zone 2
-

Zone 1:
This zone enclosed by the perimeter ground beams of grids A, E, 1, 15 (approximate 8400 m 2).
In this zone, the slab is 300 mm thk., and finished level is mostly GL +0.00m
Most of concrete work of Slab on Grade is in this zone.
To ensure the quality of concrete work and finishing, the casting in this zone will be divided into
15 stages on each area 30m long x 20 m wide as illustrated above.
In each stage, the concrete slab will be done following the sequence:
 1st : Casting of Isolation blocks around the related columns.
 2nd: Casting the Slab.

Isolation Slab (1st cast)

Slab on grade (2nd cast)Slab
(1st cast)

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-

Zone 2:
This zone enclosed by the ground beams on grids A-A1 and E-E1 (approximate 1080 m 2)
The thickness, finished level, slope of each slab area in this zone varies depended on their
designs.
The casting concrete in this zone will be done one by one to facilitate the quality control. See
details in the attached schedule.

9.2. Jointing:
There are the joints on the Slab On Grade classified as below:

a. Control joints
The control joints are designed at intervals 5.0 x 7.5m on the locations of gridlines and right on the
middle of them as typically shown below:
Gridlines
Control joints

Isolation Joints

Depend on the thickness of slabs, there are the typical control joints as below:

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The control joints are formed by using cutting machine to cut on the slab 1 day after finishing
concrete work. The lines to cut are marked on the slab with the support of theodolite.
The cut line will be 5mm wide and 50 or 70mm deep depend on the thickness of the slabs.

b. Construction joints:
The construction joints will be located at the same location of controls joints so they will be treated by
cutting in the same way of control joints. The construction joints will be formed by using formwork to
separate each cast.

Formwork will be made of rigid steel box with their top levels the same as floor finished

level. The top level of formwork is fixed by welding the steel boxes to the steel bars, which embedded
securely into bedding concrete.

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c. Isolation joints:

There are two applications of isolation joints:
-

Isolation joints along the ground beams.

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-

Isolation joints around the columns.

The isolation joints are formed by placing the Styrofoam (Extruded Polystyrene Foam) sheet 15mm
thk. before casting concrete.
After the slabs completed, a groove will be made on top by removing styrofoam 15mm deep and
replacing it with sealant such as Sikaflex.

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9.3. PVC sheets
The PVC sheets will be installed on the bedding concrete before the installation of reinforcement with the
thickness designed as below:
-

PVC sheet 0.15mm : For all areas of Slab on Grade, except storage areas.
PVC sheet 0.30mm: For the storage areas as shown below:

9.4. Steel work
•

•

Steel reinforcement works mostly are wire mesh. The meshes will be placed in compliance with
the designed layout and ensure the lap length.
The spacer blocks 5cm thk. will be placed at interval 800x800 (mm) under bottom layer. The bar
chairs will also be placed with spacing 800x800 (mm) to support the top layer to the right
position and concrete cover.
At Construction joints, the smooth dowel bars D12 will be installed at spacing 500 mm as shown
below before 1st casting. The dowel bars will be support to right position with the D10
underneath, which are supported by bar chairs D10@600.

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•

After finishing 1st cast, the exposed half of steel rebars will be painted to allow their movement
later.
Around the columns, reinforced rebar will be installed followed the design, typically as shown
below:

9.5. Built-in steel angle:
As designed, the galvanize steel angles 5x50x50 mm will be installed for the shutter doors
There are 40 pieces, 4.05 m long to be installed at 17 positions before casting concrete.
These galvanized angles will be manufactured, galvanized and delivered to site before
installation.

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After placing in the right positions, levels, their fish-nail rebar will be stick weld to the starter
bars, which extruded from the ground beams, to prevent any displacement during concreting
work.

9.6. Concrete work
a. Construction joint:
The construction joints will be determined as mentioned above.
After finishing each cast, the formwork at construction joint will be removed. All rubbish, laitance
and loose materials must be cleaned before any next installation of wire mesh.
Before next casting, the construction joints will be cut to straighten the edge.

•

d. Supply and placement of concrete:
Concrete will be transported from batching plant to site by mixer truck, the slump of concrete
Ensure concrete will be

•

Ready mixed concrete from mixer truck will be then discharge to concrete pump which is set-up

•

must be within 12 ± 2.0 (cm), initial setting time: 3 to 5 hours.
delivered in uniform and continuous supply for each concrete pouring.
The interval for
Slump test is to be done for
each truck is to be on time to ensure a continuous flow of concrete.
every truck.

near the construction area.
The concrete for Slab on Grade will be pumped to place from the far to the near corners of slab.

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e. Vibrating concrete:
During concrete discharge, wet concrete shall be vibrated with a poker vibrator
especially at edges or beam area. The vibrator shall be inserted vertically into the
concrete.

f. Floor finishing
Floor finishing consists of Five major steps:
-

Striking-off
Flatness Enhancement
Application of floor hardener.
Floating (power trowel)
Trowelling to Dense Smooth Finish

Striking-off: Also known as screeding by using screed vibrator on the installed rails, is the process of
leveling the fresh concrete. It takes place immediately after the placing and compacting operations. It is
important to have good accuracy in striking to achieve floors flatness and levelness.
Concrete finishing level will be permanently controlled by rails installed along casting direction.
Using spreading vibrator and straight bar to spread and level the concrete.
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The rails are made from D20 steel pipes placed on top of the adjusting support D10. The rails are placed along
sides of each cast area at interval 3.7m to suit with length of screeding vibrator. These supports will be fixed

to bedding concrete by drilling at spacing 0.8m.

Flatness enhancement: The flatness of the floor is further enhances by flat floor tools and
equipment. These equipment includes straight bars, hand trowel and bump cutter.

g. Application of hardeners:
Spread evenly floor hardener on semi-hardened concrete. Divide the floor areas into grids
and ensure that appropriate amount of floor hardener is applied evenly onto each area. Ensure
the workers use appropriate foot ware or platform so not to leave shoes mark on the concrete
surface.
The hardener product will be spread on surface of concrete in compliance with required dosage of 4kg/m 2.
The hardener will be applied by hand two times with the sequence below:
i.

Screeding and fill floating (bull floating) shall take place before the emergence of bleed water.

ii.

After excess bleed water has evaporated or has been removed, but leaving sufficient moisture at the
surface to hydrate cement binders in the floor hardener, evenly distribute approximately 2/3 of the
hardener specified for the area. When workmen spread the hardener by hand, a sidearm motion at a
low angle to the surface is correct. In no event should the hardener be applied from distances greater
than 3-4 meters. If the hardener breaks through the surface when being applied, the concrete is too
plastic for product application. Delay application until surface stiffens slightly.

iii.

When the applied material darkens slightly from absorbed moisture, it should be floated, using hand
wooden floats and/or power trowels with kickoff float shoes (do not use combination float and

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trowel blades). Care should be taken not to tear through the surface of the hardener to the
underlying concrete. Delay applying more hardener until moisture from the underlying concrete has
been worked completely through the hardener.
iv.

Immediately apply the remaining 1/3 of the specified amount of hardener. The moisture from the
underlying concrete must be completely worked through the hardener. If this does not occur, the
floor surface will delaminate.

h. Trowelling:
Float by using power trowel machine to get smooth surface.
After the concrete has further stiffened, it should be machine or hand troweled to a blemish free
finish. Care should be taken not to trowel-burn the surface.

i. Curing:
Immediately after final troweling the slab will be cured. To prevent surface delamination, wet curing should
not begin until 24 hours after the final troweling. During interim 24 hour period, cover concrete with plastic
sheets to prevent rapid evaporation of surface moisture.
The concrete will be cured with water during 7 days.

9.7. Protection against Damage
The concrete sla b shall be protected from damage due to load overstress, heavy shock and excessive
vibration, surrounding the concrete area particularly during curing period.

Construction load shall not be placed on newly completed floor.
Traffic should be kept off the finished floor for 3 days or longer to avoid surface damages and scratch
marking.
All finish concrete surface shall be protected from damage by construction equipment, materials or other
heavy tools with the rubber sheets at the locations where the other construction work to be executed, such
as brick work or plaster work.

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10. TOOL & EQUIPMENT
The equipment to be used for the construction of s is listed below.
Item

Unit

Q’ty

ea.
nos
Nos

2
2
6

Hammer machine

Nos.

1

Walk behind trowel machine
Ride on trowel machine
Portable steel cutter

nos
nos
Nos

Straightening machine

Nos

2
1
2
1

Cutting machine
Welding machine
Bending machine
Hack-sawing machine
Screwdriver /Drilling machine
Level machine

Theodolite

Nos
Nos
Nos
Nos
Nos
Nos
Nos

Concrete pump
Spreading vibrator, L=4.0m
Concrete Vibrator

Description
Boom 45m long
Gasoline

2
8
2
4
6
1
1

Remarks
Pumping concrete
Vibrate concrete
For roughening concrete

surface
Surface finishing
Surface finishing
For cutting steel bar
Use for reinforcing steel work
Diameter <8mm
Use for reinforcing steel work
Use for reinforcing formwork
Use for reinforcing steel work
Manufacturing formwork
Manufacturing formwork
Control the elevation
Locate the gridline

11. MATERIALS
11.1. Type of material:
a/ Concrete: ready mixed concrete (supplied by KOA)
•

For structure: grade B20

b/ Steel rebar: (supplied by KOA)
•
•

With Diameter < 10mm: SR295
With Diameter >10mm : SD390, B15-B35

c/ Form work:
•

•

Plywood, 18mm thk. reinforced with steel boxes 40 x 80 x 2.0 (mm)
Styrofoam: 2.0 cm thk.

d/ Chemical:
•

SIKAFLEX Construction

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