Method Statement of RC columns

GENERAL This method statement describes the methodology for Reinforced Concrete column construction.Work will be executed in accordance with Technical Specification includes steel works,

Revision History

Submitted by ACSC

Prepared by Lương Văn Lượngng Văn Lượngng Deputy Site Manager

Reviewed by Ph m Vũ Namạm Vũ Nam Site Manager

Approved by Nguy n Vănễn Văn

1 INTRODUCTION 4

1.1 GENERAL 4

1.2 DEFINITIONS: 4

2 BUILDING DESCRIPTION: 5

3 ORGANIZATION CHART 8

3.1 Organization Chart 8

3.2 Assignment 9

4 SCHEDULE 9

5 SPECIFIC STANDARD 9

6 SCOPE OF WORKS: 10

7 FLOW CHART AND DIRECTION OF WORK 12

8 PREPARATION WORKS 13

9 CONSTRUCTION METHOD 14

9.1 Preparation: 14

9.2 Installation of working platform 14

9.3 Installation of steel bars 15

9.4 Formwork installation: 17

9.5 Concrete work 19

9.6 Curing: 19

10 TOOL & EQUIPMENT 20

11 MATERIALS 20

12 MATERIALS HANDLING, STORAGE AND DELIVERY 21

13 QUALITY CONTROL 21

14 RISK ASSESSMENT 23

15 SAFETY PLAN 23

16 APPENDIX 24

1 INTRODUCTION

1.1 GENERAL

This method statement describes the methodology for Reinforced Concrete column construction.Work will be executed in accordance with Technical Specification includes steel works, formworksand casting concrete

The construction of column will be start from stump columns or ground beams (with Ground FloorColumns) and from 1st floor to the roof Column construction will resume at least one day aftercasting of concrete of floor slab

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

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

Description:

- Building purpose : Factory

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

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

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

Deputy Site Manager 1

NGUYỄN HOÀNG TRINH (MP:090 291 1235)

nghoangtrinh@acsc.com.vn

Deputy Site Manager 2

LƯƠNG VĂN LƯỢNG (MP: 093 734 3055)

Thái Doãn Long (MP:097 799 7711)

thaidoanlong@acsc.com.vn Shop Drawings

Hoàng Văn Hải (MP:908 818 1059) Nguyễn Anh Đức (MP:0986 274 758)

Safety Supervisors

Phạm Văn Mạnh (MP:097 235 2459)

Đỗ Vũ Quyền Anh (MP:090 853 1908)

Construction teams

3.2 Assignment

NGUYỄN MINH TUẤN

VÕ CÔNG HIẾUTRƯƠNG THANH VIỆT

4 SCHEDULE

Construction Schedule of Columns is attached in Appendix-2

5 SPECIFIC STANDARD

Reinforced Concrete Columns shall be carried out in accordance with the requirements of:

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

- On Ground Floor, there are total 123 columns with section vary from 30x30 (cm) to 50x50 (cm).Their heights vary from 6.15m to 6.45m high (from top of ground beams/stump columns to thebottom of 1st floor beams GFL+ 6.15)

Hereafter is the list of columns from ground floor to 1st floor:

- On 1st floor, there are 92 RC columns with section vary from 30x30 (cm) to 50x50 (cm) Theirheights vary from 3.99 to 5.81 m (from 1st floor GFL+7.250 to the bottom of rafter).

Hereafter is the list of columns from 1st floor to the roof:

7 FLOW CHART AND DIRECTION OF WORK

The work sequence of construction the RC Columns is shown at the following flow chart

Preparation concrete surface and

starter bars

Installation scaffolding & platform

Rebar fabrication Installation steel rebar

Formwork fabrication Installation of form work

Casting concrete

Final casting concrete

For columns from 1FL to the

roof only

Install anchor bolts

Curing concreteRemoving formwork

8 PREPARATION WORKS

- Scaffolding preparation:

+ Scaffolding will be installed aside the column 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

+ 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

- Concrete work

+ Cover starter rebar by PVC sheet before casting

+ Prepare bucket or chute for casting from top to bottom

+ Order the concrete

9 CONSTRUCTION METHOD

9.1 Preparation:

- Concrete surface preparation and column starter bars shall be done first before proceed to the reinforcing bar installation With Ground floor, the concrete surface are on top of Ground beams

or stump columns With 1st Floor, the concrete surfaces are on concrete slab

- All laitance and loose material at column location at the top of concrete shall be removed; this will be served as construction joint between concrete slab and RC column Dust and loose material will be cleaned by means of air compressor or water

- Make sure that starter bars for column are free from concrete laitance before start the

installation of reinforcing bars

- The gridlines and column perimeters will be marked directly on finished concrete surface to locate and shape the columns

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

9.2 Installation of working platform

- Scaffolding shall be installed at every column location, this will serve as casting concrete

SCAFOLDING FOR WORKER

STEEL SUPPORT TRANSOM

SUPPORT STEEL PROP D49

STEEL LADDER STEEL PLATFORM STEEL HANDRAIL

9.3 Installation of steel bars

- Fabrication and Installation of rebars shall be done according to the approved working drawings and project specification, conforming to the specified splicing length, splicing location and standard concrete covering

- Starter reinforcing bar of column will be checked based on the survey layout, plumbness of this starter bars shall be check prior to the overlapping of the next main bar

- Start lapping of column main bars by tie wires to the embedded starter bars on slab following required lapping length and approved staggered splicing location After completely installed the column main bars, stirrups spacing shall be marked on the column main bars prior to the stirrups installation Then tie bars will also be provided based on the design spacing

TYPICAL PLAN

- 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:

Fine stone (dmax=10mm) : 99 liter

- In some cases where the column size is design to be reduced in upper floor level the rebars will

be slightly bended and some rebars need to embed considering the embedment requirement Basically, design of rebars for column reduce in the upper floor level, therefore some rebars also need to cut at designated level Please refer to the figure below for sample case of Reinforced Concrete column design

9.4 Formwork installation:

In general, the maximum height of column is on Ground floor heights from 6.15m to 6.45m

- Reinforcing bar inspection shall be carried out first prior to close column formworks

- Using pre-fabricated formwork panels which have the width varies from 300mm to 500 mm Design sizes of columns will be met by combining different width of panels These panels will be assembled with tie rod on 2 sides and steel bracing boxes on two other sides Basically this supports will be applied to bear the lateral concrete pressure The distance of tie rod and steel bracing boxes is determined via calculation in the Appendix No.3

- The distance of tie rods will vary depend on the height of casting concrete From the bottom to the height 1,5m (from the ground), the distance of tie rods is 250mm From the height of 1.5m to3.0m, this distance is 0.4m From the height of 3.0m to the top, this distance is 0.5m

- At the corners of columns formwork, the triangular wood strips will be nailed into the plywood toform the chamfers 15x15 (mm) of columns.

- Using steel pipes supports to horizontally and vertically straighten the formwork panels will be provided, this will be installed up to top of formwork The bottom of steel props will be fixed and supported by timber blocks, which are fixed on the ground with stake or on the finished RC slab with nails See figure as typical formwork elements below.

- At the height above 3.0m, the cable D10mm and turnbuckle will be used to fix and adjust the plumpness of formwork system

- Apply the sealant or similar material around the bottom of formwork to prevent the leakage

VERTICAL SUPPORT BAR STEEL BOX 50X50X2 SCAFOLDING FOR WORKER

FIXED STAKE SCAFOLDING FOR WORKER

OPENING HOLD SIZE: 150X300

STEEL LADDER STEEL PLATFORM

STEEL HANDRAIL SAFETY BODY HANESS COLUMN START REBAR

- Using theodolite and plumb bob, the shape and alignment of formworks will be checked Column formwork panels will be propped and adjusted with steel propping combining with cable and turnbuckle

- Concrete will be cast layer by layer with the thickness not greater than 50cm then be vibrated with concrete vibrator inside

- Using the poking vibrator with the rod at least 8m long to ensure the poking reach to the bottom

of columns (first cast)

- At each 3.0m high of column concrete, the casting will be paused at least 30 minutes before resume to allow concrete consolidation, consequently there will be 2 casts of each columns 6m high The time for each cast 3.0m is approximately 30 minutes Total the time to complete each column is about 30 + 30 + 30 = 90 minutes

- Columns finish level of concrete at desired levels With the columns of Ground floor, the

concrete of columns will be finished at the bottom levels of slab beams With the columns of 1st

floor, the casting concrete will be temporarily stopped at the bottom of anchor bolts of rafter After the anchor bolts are set, the remaining concrete will be cast to the design levels (bottom of rafter) The additional stage will facilitate the casting and vibration of concrete without the obstruction of anchor bolts and their template

9.6 Curing:

- The formwork of columns will be removed after 24hrs

- The concrete will be cured with Antisol E- a curing agent produced by SIKA with density

4-6m2/liter (See Appendix 7) An alternative is using canvas fabric to wrap the columns and watertwice every day

- The curing will long at least 7 days

10.TOOL & EQUIPMENT

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

y Remarks

1 For roughening concrete surface

Diameter <8mm

11.MATERIALS

a/ Concrete: ready mixed concrete (supplied by KOA)

- For structure: grade B20

- 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

12.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 The surface of formwork must be clean of dirt, loose concrete and to be applied the release agent, if needed

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

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 columns will comply with KOA ITP shown in Appendix 4

14.RISK ASSESSMENT

See attached Appendix No.5

15.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

equipment should be done

Forman / Supervisor / Worker