Method Statement of RC suspended slab

The work sequence of construction the RC 1FL slab is shown at the following flow chart.Previous stage Columns underneath suspended slab Casting lean concrete of ground slab Casting conc

SMC-Factory No.1/MS-RC 1FL slab Page 1

Prepared by Lương Văn Lượngng Văn Lượngng Deputy Site Manager

Reviewed by Nguy n Hoàng Trinhễn Hoàng Trinh Site Manager

Approved by Nguy n Văn Trungễn Hoàng Trinh Project Manager

1 INTRODUCTION 4

1.1 GENERAL 4

1.2 DEFINITIONS: 4

2 BUILDING DESCRIPTION: 4

3 ORGANIZATION CHART 8

3.1 Organization Chart (Factory No.1) 8

3.2 Assignment 9

4 SCHEDULE 9

5 SPECIFIC STANDARD 9

6 SCOPE OF WORKS: 10

7 FLOW CHART AND DIRECTION OF WORK 10

8 PREPARATION WORKS 12

9 CONSTRUCTION METHOD 13

9.1 Installation scaffolding & support: 13

9.2 Installation of formwork 14

9.3 Installation of steel bars 16

9.4 Concrete work 17

a Construction joint: 17

b Casting sequence: 18

c Leveling concrete surface: 20

d Curing: 21

10 TOOL & EQUIPMENT 22

11 MATERIALS 23

11.1 Type of material: 23

11.2 Materials handling, storage and delivery 23

12 QUALITY CONTROL 24

13 RISK ASSESSMENT 25

14 SAFETY PLAN 25

15 APPENDIX 26

SMC-Factory No.1/MS-RC 1FL slab Page 3

1 INTRODUCTION

1.1 GENERAL

This document describes the procedures and method of work for carrying out the construction worksfor RC slab of building factory No.1 This method statement will be applied for first floor (level +7.250m).Construction work of this slab will be repeatedly carried out after s underneath columns completed Theconstructions of columns were carried out by previous stage; therefore they will no longer discuss in thismethod 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

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

Description:

- Building purpose : Factory

- Foundation : Spun piles (D300, 350, 400 mm)

- Structure :RC structures + steel rafter; Slab on grade

o Utilities area: 2 x (120m long, 4.5m wide)

SMC-Factory No.1/MS-RC 1FL slab Page 5

Factory No 1

o Factory Ground floor slab : 300 mm thk

o Storage/Utilities Ground Floor slab : 150 mm thk

GFL+7.2501FLGFL+11.900T.O.BEAMGFL+13.650T.R.BEAM

CANOPY; STEEL BEAM

CORRIDOR ZINC ROOF SHEET

TYPICAL CROSS SECTION

3 ORGANIZATION CHART

3.1 Organization Chart (Factory No.1)

SMC-Factory No.1/MS-RC 1FL slab Page 9

Deputy Site Manager 2

LƯƠNG VĂN LƯỢNG (MP: 093 734 3055)

Nguyễn Minh Tuấn (MP: 098 314 5069)

Nguyễn Văn Hào (MP: 0938.722.730)

3.2 Assignment

NGUYỄN VĂN HÀO

LÊ VĂN TUẤTBÙI CÔNG HUYNH

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

6 SCOPE OF WORKS:

The 1FL suspended slab include main area 140m long x 60m wide and the sub-area along grid A & E

The finished level of slab mostly is +7.250 (m) from the Ground floor Some areas have the finished levels at 0.05 or -0.15m (in compared with 1FL)

-The RC members are listed as below:

The RC beams are divided into:

Main beams: supported directly on columns

Secondary beams: supported on main beams

7 FLOW CHART AND DIRECTION OF WORK

SMC-Factory No.1/MS-RC 1FL slab Page 11

The work sequence of construction the RC 1FL slab is shown at the following flow chart.

Previous stage

Columns underneath suspended slab

Casting lean concrete of ground slab

Casting concrete

Curing concrete

Install rails for leveling

Final cleaning

MEP conduits embedment (by others)

Installation of steel rebarRebar fabrication

Installation formworkFormwork fabrication

Installation scaffolding & supports

8 PREPARATION WORKS

- Scaffolding preparation:

+ Scaffolding will be installed aside the and be propped/braced securely

+ Install platform and handrail on each story of scaffolding

+ Provide the ladder on scaffolding from the ground to the working level

- Surface preparation

+ Chip out and remove all debris, loose material on top surface of s

+ Cleaning the surface on the top of s 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 1FL s, 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 determined in Technical Specification for each kind of structures The concrete proportion

is proposed for one mix as below:

+ Cover starter rebar of s by PVC sheet before casting

+ Prepare the location for concrete pump

+ Order the concrete

SMC-Factory No.1/MS-RC 1FL slab Page 13

9 CONSTRUCTION METHOD

9.1 Installation scaffolding & support:

- The scaffoldings for support are divided into two kind:

o For beams: using steel supports 1.0 x 1.0 (m), included 4 props of D49 segment 2.5+ 2.5+ 1.0 (m) bracing with D42 steel pipes and their accessories such as base/top jack These steel supports are braced together with D49 steel pipes and clamps

o For slab: using scaffolding 1.25 x 1.50 (m), mostly included 5 layers: 4x 1.5 + 0.9 (m), which are continuously connected together

Typical layout of scaffolding for beams and slab is shown as below:

All scaffoldings/ supports will be installed on base jacks directly placed on lean concrete of ground floor The supports of beams and slab are also braced together by using D49 steel pipes and clamps to form a secure system

Support of SlabSupport of Beams

See attached drawings for more details.

9.2 Installation of formwork

- Before any use, all the plywood surface will be applied the release agent

- The elevations of beam bottom and slab will varies depend as designed See attached drawings for more detail

- Formworks of the beam shall be installed first Gridline will be clearly marked on the top of s.Beam formworks will be made by plywood and supported by rectangular steel box 40 x 80 mmfor side and bottom of the beam

SMC-Factory No.1/MS-RC 1FL slab Page 15

- Tie rods will also be used through PVC pipes which have a diameter of 10mm to bear the lateralpressure of concrete After casting concrete and take out formwork, this hole from PVC pipe will

be treated and filled with mortar See typical detail below

- Formworks of the slab shall be installed next The secondary girders, steel boxes 2(4x8) cm areplaced on top of scaffolding along the number grid lines The primary girders- steel boxes 8x4(cm) will be placed directly under plywood at distance 400 mm See typical detail below

9.3 Installation of steel bars

- Fabrication and Installation of rebar shall be done according to the approved working drawingand project specification This will also carry out considering the specified splicing length, splicinglocation and standard concrete cover

SMC-Factory No.1/MS-RC 1FL slab Page 17

- Slab rebar or stirrups spacing will also be marked particularly the design spacing Rebar will beinstalled based on the design layout Concrete or mortar blocks will be used as spacer for side inorder to keep the appropriate concrete covering

- Beams reinforcement consists of main rebar and stirrups will be assembled first Concrete spacerwill be placed both sides of beams and bottom to get appropriate concrete cover

- Then slab reinforcement bars (bottom and top layers) will be installed next Concrete spacer will

be placed at the bottom layer of slab The top layer of slab will be supported with steel chair toget appropriate concrete covering

- At intersection of main and secondary beams, the top bars (of main beam) and bottom bars (ofsecondary beams will be cranked to maintain the design concrete covers as illustrated below

Secondary beamBottom bar of Secondary beam to be cranked

- The formwork of construction joints are made of steel boxes 2x4, 4x8 (cm) or plywood as illustrated below The construction jonts will be reinforced with D10@200 for slab as instructed

- Concrete will be transported from batching plant to site by mixer truck, the slump of concrete must be within 12 ± 2.0 (cm)

- Ready mixed concrete from mixer truck will be then discharge to concrete pump which is set-up near the construction area how its boom can reach to the casting slab

- Concrete will be cast from a corner of slab to the opposite corner generally with two steps:1/ Beams will be cast first and well vibrated Only the beams in the zone of casting will be cast to avoid waiting time longer than set time of concrete

STEP 1

WELL VIBRATE

2/ Continue pour concrete of slab

c Leveling concrete surface:

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

The rails are made from D20 steel pipes placed on top of the adjusting support D10 The rails are placed alongsides of each cast area at interval 3.7m to suit with length of screeding vibrator These supports will stand on concrete blocks, which are fixed to formwork plywood with nails and tie wire at interval 0.6m After removal

of formwork, these nails will be cut off

SMC-Factory No.1/MS-RC 1FL slab Page 21

LEVELING THEN TROWELLING

3/ Troweling by machine will be carried out to get smooth surface after 2-3 hours.

d Curing:

- The concrete will be cured with water during 7 days

- Formwork system will be removed when test result of concrete reach to 80% of designed strength, side formwork will be removing after 1 day from finished time casting concrete

10.TOOL & EQUIPMENT

The equipment to be used for the construction of s is listed below

Equipment

Steel support D49, L=2.5m With joint pcs 3500 For beams support

Steel support D49, L=2.5m Without joint pcs 3500 For beams support

Steel support D49, L=1.0m Without joint pcs 3500 For beams support

0 For beams support

For roughening concretesurface

SMC-Factory No.1/MS-RC 1FL slab Page 23

Portable steel cutter Nos 2 For cutting steel bar

Diameter <8mm

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)

- Wooden strip to form chamfer 15x15 (mm)

d/ Curing agent:

- SIKA Antisol-S

11.2 Materials handling, storage and delivery

- Concrete : Ready- mixed concretes are transported from batching plant to site in concrete truck (6

to 12 m3 capacity) The concrete must be delivered to site within maximum 60 minutes depend

on the mix design of concrete supplier

- Formwork : Formwork will be pre-fabricated then stocked on yard with protection of plastic cover Before installing, the formwork will be transported to site and placed near the excavation

Unloading reinforcement from trailer by a suitable crane for lifting up reinforcement bundles.Prior to fabrication of reinforcement, samples shall be taken from each batch of each size of each delivery and tested for compliance in accordance with Quality Control procedures.

- Other materials are keeping in storage and they are transported to the site work when they are

in used

12.QUALITY CONTROL

With regards to the quality control, all works shall be carried out following the established Project Quality Control Plan

Installation of form work

+ Check by leveling machine, tape

+ Check tightness of formwork by visual

+ Check rigidity and stability of bracing

- Installation of rebar

+ Checking material: certificate, check dimension by caliper, take the sample for checking

physical-mechanical

+ Check the length, number, position, anchor length, joint by visual and ruler

+ Thickness of protection: checking by tape

+ Lap length: Rebar SD390 Ribbed bar: 40d (tensile), 15d (compressive)

The tolerance of works related to beams & slab will comply with KOA ITP shown in Appendix 4

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13.RISK ASSESSMENT

See attached Appendix No.5

14.SAFETY PLAN

With regard to health and safety control, all the works shall be carried out following KOA Safety

regulations Some of safety measures are shown as below:

during installationrebar, formwork

+ Accident duringcasting concrete+Falling objectfrom the height

Injury or death to workers or operators

+ Install scaffolding to providesufficient working area onplatform

+ Install the ladder forescalation

+ Install handrail aroundplatform

+ Install warning tape, barrier

to stop person enter theworking area

Forman / Supervisor / Worker

Installation and

Concreting Works

Fall down of concrete equipment accessories worker hit by these falling objects

Injury of people/

worker

+ Workers must alert wheninstallation of heavy steelmaterials

+ Wear protective equipmentduring

+ Installation and concreting works

Forman / Supervisor / Worker

collapse

Injury of people/

worker

+ Scaffolding must beinstalled on firm and securebase

+ Using base jack to adjustthe level of scaffoldingbase

+ Using steel prop to supportthe scaffolding

+ Bracing the singlescaffolding together

Forman / Supervisor / Worker

Injury of people/

worker

+ Provide qualified personnel

to do and supervise the job

Forman / Supervisor

Condition

Scattering of dirt/

garbage and some chemicals

Damage to neighborhood inhabitants

+ Avoid leaking of chemicalsand other solution

+ Keep the site clean before stop

working

Forman / Supervisor / Worker

Equipment

Oil spillage to earth

Damage to neighborhood inhabitants

+ To make sure all machineryfree of oil leak

+ Repairing/maintenance of

Forman / Supervisor / Worker