Report of method statement mong duong project

10 2.3.3 Inspection of Excavations All excavations are to be inspected and must be approved by VINACONEX E&C engineer before gravel and lean concrete is laid in case the work is carried

CONTENT

CHAPTER 1 TEMPORARY WORK & PREPARATION 4

1.1 GENERAL 4

1.2 SITE INSPECTION, ATTACHING BATTER BOARDS, SCAFFOLDING 4

1.3 TEMPORARY ACCESS ROAD 5

1.4 MATERIAL STORAGE YARDS, CONSTRUCTION SHEDS AND OTHER

TEMPORARY WORKS 6

1.5 REMOVAL OF TEMPORARY UNITS AND OTHERS 6

CHAPTER 2 EARTH WORK 7

2.1 GENERAL REQUIREMENT 7

2.2 EARTH WORK SUPPORT 8

2.3 METHOD OF EXECUTION 8

CHAPTER 3 REINFORCEMENT WORKS 12

3.1 MATERIALS 12

3.2 PROCESSING AND ASSEMBLY 12

3.3 ARRANGEMENT OF BARS 13

3.4 HOLES IN BEAMS AND OTHER CASE 13

CHAPTER 4 FORMWORKS 15

4.1 MATERIALS AND CONSTRUCTION 15

4.2 ASSEMBLY 16

4.3 FORMWORK INSTALLATION 17

4.4 FORMWORK REMOVAL 17

4.5 HEAD TREATMENT FOR FORM TIGHTENING PARTS 18

CHAPTER 5 CONCRETE WORK 19

5.1 GENERAL 19

5.2 CONCRETE CASTING PLAN 19

5.3 MATERIALS FOR NORMAL WEIGHT CONCRETE 20

5.4 MIX PROPORTION OF ORDINARY CONCRETE 20

5.5 PRODUCTION, TRANSPORT AND PLACEMENT OF CONCRETE 21

5.6 TESTING 24

5.7 TROWEL FINISH FOR FLOOR CONCRETE 25

CHAPTER 6 ERECTING COMPONENTS 27

6.1 GENERAL CHARACTERISTIC OF EXECUTIAT THE SITE 27

6.2 EXECUTED ORGANIZATION 28

6.3 ORGANIZING AND WORKING METHOD 29

6.4 ERECTING METHOD 31

6.5 GENERAL REGULATION 37

CHAPTER 7 STRUCTURAL STEEL WORK 38

7.1 GENERAL 38

7.2 MATERIALS REQUIREMENTS 38

7.3 GENERAL SHOP DRAWINGS 39

7.4 ANCHOR BOLT SETTING 43

7.5 WELDED JOINTS 45

7.6 PAINTING 50

7.7 OTHER NOTICES ON FABRICATING STEEL STRUCTURES 50

CHAPTER 8 FINISHING WORKS 52

8.1 WATERPROOFING 52

8.2 BRICK WORK 53

8.3 DOOR FRAMES INSTALLATION 53

8.4 PLASTER WORK 55

8.5 TILE WORK 57

8.6 PAINTING WORKS 61

8.7 CEILING WORK 62

8.8 METAL WORK 63

CHAPTER 9 INTERNAL ROAD 65

9.1 ROADWAY EXCAVATION 65

9.2 METHOD APPLIED FOR CONSTRUCTION OF SUB-GRADE 65

9.3 THE METHOD APPLIED FOR CONSTRUCTION OF BASE AND SUB-BASE COURSE 66

9.4 THE CONSTRUCTION METHOD OF ROAD STRUCTURE 68

CHAPTER 10 HSE PLAN 74

10.1 GENERAL 74

10.2 SAFETY ORGANIZATION: 74

10.3 SAFETY PLAN: 75

10.4 SAFETY REPORTS: 85

10.5 NOTIFICATION OF ACCIDENT: 85

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accordance with specifications or instruction of the Engineer

Major sequence and plan for construction

1.2 SITE INSPECTION, ATTACHING BATTER BOARDS, SCAFFOLDING,

Etc

1.2.1 Checking Site Conditions and Staking Out

After verifying the conditions on site, the location of the building shall be indicated by staking out or other suitable method and this shall be inspected by the Engineer

Benchmarks shall be inspected by the Engineer

1.2.3 Attaching Batter Boards

After staking out the site, install batter boards at the corners and other important points of the building, and provide temporary making for setting line

at a place where the work will not be affected

The top of the batter board shall be planed using a planer and attached horizontally to the ground stakes with nails

When attaching batter boards clearly indicate the location of the building and horizontal reference and ask the Engineer to inspect the batter boards

1.2.4 Scaffolding

Scaffolding, landing stages, temporary enclosures etc shall be built with appropriate materials and structures in accordance with the labor law, building standard law, requirements for public disaster prevention in construction and other relevant laws

1.3 TEMPORARY ACCESS ROAD

1.3.1 Clearing and Grubbing and Tree Removal

The Contractor shall clear and/or grub, including disposal as required all surface objects and all trees, down timber, rotten wood, stumps, roots, snags, brush, other vegetation, rubbish, and other protruding obstructions not designated to remain

In area under roadway embankments, from which the topsoil or unsuitable materials are to be removed or which are designated to be compacted, the Contractor shall remove all stumps and roots to a depth at least 20 cm below the original ground surface and at least 15 cm below the bottom of the lowest pavement layer

In roadway cut area, all stumps and roots shall be remove to a depth of not less than 30 cm below the finished sub-grade level

Voids left after removal of roots shall be filled with suitable compacted materials as approved by the Engineer

1.3.2 Topsoil Stripping

The Contractor shall remove the topsoil in area under roadway embankment or where designated by the Engineer, and stockpile / dispose of it to the approved area as directed by the Engineer

When the topsoil will be used for dressing of the slopes of the embankment or other area as directed by the Engineer or as indicated on the drawings, the Contractor shall place and spread the stockpiled topsoil in such designated area After spreading, the topsoil shall be raked to form a smooth surface free from weeds, roots, sods and large stones

Removal of topsoil shall be executed to the depth as directed by the Engineer, and the topsoil shall be kept separate from other excavated materials

1.3.3 Disposal of Cleared Materials

All cleared material is the property of the Engineer and shall be used or disposed of as the Employer sees fit

The Contractor shall haul all cleared material from the clearing and grubbing

operation to locations designated by the Engineer No accumulation of debris shall remain on or adjacent to the right-of-way

1.4 MATERIAL STORAGE YARDS, CONSTRUCTION SHEDS AND

OTHER TEMPORARY WORKS

1.4.1 Materials storage yards

Material storage yards or construction sheds, etc shall be allocated and constructed to suit the stored material and depend on site organizing plan 1.4.2 Storehouses for explosives

Storehouses for flammable materials such as paints and oil shall conform to the relevant laws and be situated as far as possible from buildings, construction sheds, material storage yards etc The roof and interior and exterior walls and ceilings shall be of fire-preventive construction or be covered with a fire protection material; each door shall be lockable, and provided with a

"CAUTION: FLAMMABLES" notice and fire extinguisher

1.4.3 Contractor's Offices and other rooms

The contractor's office, toilet, etc shall be provided

Signboards displaying the name of the construction work, name of owner and other details shall be installed at a suitable location on the construction site

1.5 REMOVAL OF TEMPORARY UNITS AND OTHERS

If a temporary construction is disturbing the progress of work or the use of other buildings within the premises, then the contractor shall negotiate with the Engineer for its removal

In the event that there is no place to move the temporary construction, then part of the construction may be used if approved by the Engineer

The temporary constructions should be removed, the construction area as well nearby areas cleared and cleaned and the ground surface leveled before the formal completion of the construction work

2.1.2 Excavation and backfilling

Excavation should be suited to the situation in surrounding areas, geology and groundwater conditions, and slope surface protection or landslide protection shall be employed in accordance with the relevant laws so as to prevent the collapse of sediment

Where buildings adjacent to the excavation area are likely to be collapsed or broken, adequate measures shall be taken in advance to prevent such occurrences

Where underground water supply or drain pipe, gas pipe or cables are likely to

be discovered, a survey shall be conducted In the event that a buried object is found, it shall be carefully handled so as not to cause damage All necessary emergency measures shall be taken, and the final outcome shall be determined through discussing with the Engineer and/or the authority concerned

All minor obstacles to construction work shall be removed The treatment of major obstacles shall be discussed with the Engineer

The bottom of cutting shall be excavated without disturbing the ground, and inspected by the Engineer upon completion of the excavation

2.1.3 Drainage

Rainwater, spring water, stagnant water, etc that may hinder construction shall

be removed via drain ditches, catching basins or pumps Where unusual freshet is seriously affecting the execution of the work, this matter shall be brought to the attention of the Engineer

Appropriate measures shall be taken before draining water from the excavated area so as not to influence the bottom of the cutting, the surface of slope, construction site or neighboring areas

2.1.4 Backfilling and Filling

Prior to Backfilling, remove formwork and other objects located in the area to

be backfilled Consult the Engineer in the event that formwork shall remain as they are

Consult the Engineer if the excavated soils are not suited to the backfilling and fill

Extra fill settlement or allowance may be required depending on the soils

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2.1.5 Grading

Grading (leveling) shall be performed for a width of approximately 1m around the building in order to drain away water

2.1.6 Disposal of Earth Generated during Construction

Earth generated from the construction work shall be transported outside the premises and disposed of in a suitable manner in accordance with local regulations

In the event that some of earth generated from the construction work can be reused, under consultation with the Engineer and/or the local authority

2.2 EARTH WORK SUPPORT

Earthwork shall be supported safely and securely in accordance with the local regulations and/or the Engineer’s directions

Earthwork supporting system shall be submitted to the Engineer for approval with calculation sheet

During execution due attention should be given to the stress and deformation with a view to potential disasters

When installing earthwork support works, constantly check and measure the adjacent ground for potential landslides Should any abnormal state be detected, adequate steps shall be immediately taken and a report made to the Engineer

Removal of earthwork support structures shall be performed in a careful manner after verifying the safety level The holes left after steel sheet piles are pulled out shall be immediately backfilled with sand or other suitable material directed by the Engineer, thereby preventing deformation of the ground

2.3 METHOD OF EXECUTION

2.3.1 Excavation

All excavation shall be carried out to the required lengths, depths, inclinations and curvatures as may be necessary for the constructions of the work or as shown on the drawings in whatever material that may be found, including top soil and the surplus soil shall be disposed of as VINACONEX E&C engineers may instruct

Excavation for foundation shall extend a sufficient distance from the footing (approximately 50 cm) to create appropriate space for placing and removal of forms

The bottoms of all excavation shall be leveled carefully, unless otherwise on the drawing or by VINACONEX E&C engineers’ instructions

2.3.2 Excavation Process

- Machine Excavation

The purpose of machine excavation is to speed up the process Follow this procedure, excavation machine can not break the underground soil structure which according to the design of foundation Excavator will not be able to excavate the small space, but that soil will be excavated

Checking-level pole will be used to correct the level of ground during excavation by hand

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2.3.3 Inspection of Excavations

All excavations are to be inspected and must be approved by VINACONEX E&C engineer before gravel and lean concrete is laid (in case the work is carried out by a sub contractor of VINACONEX E&C) The sub contractor shall inform VINACONEX E&C engineer in time to allow VINACONEX E&C’s inspector to make the visual inspection of the excavation works

2.3.4 Additional Excavation

If it is necessary for any reason to form, extend and/or deepen foundations under or around any part of the work, the additional excavation shall be processed

2.3.5 Inspection before Filling

No filling in shall be commenced until the concrete foundations have been inspected by VINACONEX E&C engineer in charge

2.3.6 Upholding Sides of Excavation

When it is necessary, upholding the sides of excavations shall be processed to prevent any damage to adjacent structure and buildings caused by collapsing

of sides and embankments of excavations

2.3.7 Timber, etc Left in Excavations

Timbering, dust, debris, rubbish, etc Shall not be left in when excavations are being filled

2.3.8 Removal of Surplus Soil

All surplus excavated material, rubbish and waste matter shall be removed from the site The place for disposal shall be selected by site manager or by sub contractor

2.3.9 Keeping Excavation Free From Water

Powered pumping, drainage or otherwise shall be used to keep the whole of

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the excavation free from water issues which may be arised by rain, flood, drain, springs or any other cause If the work is carried out by a sub contractor

of VINACONEX E&C, they shall consult VINACONEX E&C engineer being

in charge before he starts with the excavation works that suitable equipment,

in good working condition is available on the project site

2.3.10 Conclusion

There are many important matters that we have to pay attention in order to carry out the project successfully:

- Preparation period of work: study drawing and engineering

specifications, quantity surveying, execution method

- Master schedule and detail schedule of work

- Supervision on site and meeting with all of Team every day

- Report in tomorrow’s work meeting every day (location, quantity,

transportation way)

- Writing report after the wok has been completed

cover-3.2 PROCESSING AND ASSEMBLY

Do not use gas pressure welded joints for SD 295A, or lap joints for sizes over D29

Reinforcing bars with dangerous bends, cracks, splits or other defects shall not

be used under any circumstances

Reinforcing bars in coil form shall be straightened by a straightening machine before use

Reinforcing bars shall be cut with shear cutters or saws Gas cutting is permitted where unavoidable, if approved by the Engineer

Spot welding and arc strike shall not be permitted for reinforcing bars Reinforcing bars, however, is spot-welded after preheating if approved by the Engineer

- Hooks at each end of the reinforcing bars shall be provided where:

- The main reinforcements are located at the four corners of a column, at

lap joints and at the top of column at the highest story

- The lap joints to the main reinforcement of beam are located at the

outer corners and at the both ends of the lower portion of beam, except for foundation beams

- Base reinforcing bars for pile foundation

- Hoop, stirrup and yoke bar

3.2.2 Thickness of Cover Concrete and Interval of Reinforcing Bars

The minimum thickness of cover concrete of reinforcing bars and welded wire fabric shall conform to show on the structural drawings in the Design Documents When using bars larger than D29 as the main reinforcement of columns or beams, the minimum thickness of cover concrete for main reinforcement specifications shall be calculated by multiplying the diameter

by at least 1.5

The thickness of cover concrete used for the processing of reinforcing bars for column and beam specifications shall be the sum of the minimum thickness of cover concrete plus 10mm as standards

For steel frame reinforced concrete structures, the gap between the main reinforcement and steel frame parallel to each other shall conform above

3.3 ARRANGEMENT OF BARS

Reinforcing bars for all concrete structures shall be arranged in strict accordance with the requirement shown on the structural drawings in the Design Documents, unless otherwise directed by Site Engineers

3.4 HOLES IN BEAMS AND OTHER CASE

Reinforcement of through holes in beams shall conform to the following, unless otherwise shown on the structural drawings in the Design Documents

- Diameter of the holes shall be less than one-third of beam depth If the

hole is not round in shape its diameter of circumscribed circle shall conform to the above

- Limit of the center of the hole shall be separated at least 1.2D (where D

is beam depth) from the face of a column or an orthogonal beam (small beam) as a rule

- If the holes are placed in parallel, then the distance between the centers

of two through holes shall be at least three times the average diameter

of the holes

- Vertical bars and upper and lower vertical beams shall be arranged in

the form of stirrup

- Bars of reinforcement shall be placed inside main bars or, where this is

not possible, placed inside after obtaining approval from the Engineer

- Special reinforcement may be omitted if the diameter of the holes is

less than one-tenth of the beam depth and also less than 150mm

- Excess length of welded wire fabric shall be more than one gird mesh

and projection shall be over 10mm

- Ring bar attached to welded wire net shall be welded to the wire net at

least at 4 points

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- Start point of layout for welded wire net shall be below the stirrup for

horizontal bars and at the center of through hole for vertical bar

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CHAPTER 4 FORMWORKS

4.1 MATERIALS AND CONSTRUCTION

Sheathing boards and timbering shall be used These shall be able to withstand external forces such as working load, deadweight of concrete, lateral pressure, vibration and horizontal load, and have a form which does not bring about dangerous levels of distortion or strain

Metal or wooden member shall be used in timbering

The following items shall be satisfied: For exposed concrete finishes, the finish on the concrete surface shall conform to the concrete finish surface specification

When using a steel deck instead of sheathing boards the plate for floor concrete forms shall be provided at a stable floor surface

Form tightening parts shall be bolt type, although annealed wire may be used for catch basins

Release agent (such as form oil), if applied, shall be obtained approval form the Engineer before application

Old members may be used in some cases as concrete forms: When using old sheathing boards, tightening holes or the like shall be repaired as required and surfaces completely cleaned

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4.2 ASSEMBLY

Sequence of construction for column & wall

Working drawings for concrete works shall be submitted to the Engineer for approval

The required setting-out shall be performed prior to assembly, and the most important setting shall be inspected by the Engineer

Sheathing boards shall be assembled in accordance with the location, shape and dimensions of concrete to be molded

All sleeves, boxes, metal parts to be embedded and other objects inside forms shall be firmly attached before pouring concrete Sleeves shall conform to

"through holes and other"

Supports shall be fixed vertically and directly above other supports in the lower story as a general rule

Forms shall not be connected to other temporary works such as scaffolding, batter boards, etc

When using steel deck plates as floor concrete forms, and appropriate strength shall be provided for form members to be connected together

Cones shall be used for form - tightening parts in the following locations :

- Face directly touching earth (except footings, foundation beams

without basement, etc.)

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- Backing for waterproof

- Exposed finish concrete surface

- Surface to be directly finished with thin finish material such as paint

coat, wall paper, etc

- Surface on which an insulating material is to be attached

- In order to achieve high quality of concrete work, steel form will be

used for the project Our amount of steel form is enough to meet requirement of the project In case of lack of form, additional form will

be fabricated The fabrication process includes material, tools and machine's preparation Special form will be made especially according

to structure design All of additional form is to meet the general requirements, stiff and hard enough

4.3 FORMWORK INSTALLATION

4.3.1 Marking

Marking is the first step of setting form process A grid line system must be established in advance so that marking work can base on Center- lines of structure will be made base on the established grid line's system

4.3.2 Assembly Work

All steel form must be sufficiently prepared in advanced Steel form must be cleaned and applied a thin layer of special oil to avoid concrete remaining when remove form

Foundation

Sequence of work includes placing steel form for foundation, adjust the level and verticality with a plumb bob After everything is set, start fixing with form ties and support

Form after being set must be vertical Top level of potential concrete must be marked on form surface

Column and Wall

Before setting, form must be cleaned carefully at its bottom

During process of erection form for wall and column, verticality must be checked with a plumb bob

After everything is set, start fixing with form ties and diagonal support and bracing

Form after being set must be vertical Top level of potential concrete must be marked on surface of form

4.3.3 Time of Keeping Form in Its Place

Form can only be stripped when it meets the requirements about concrete strength as standard

4.4 FORMWORK REMOVAL

Before removal of form, engineer must confirm the strength of concrete whether it is enough or not

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During process of removing, people must be kept away the area

All of material after being taken out must be well arranged and cleaned up by the form oil to the next using

Removal of forms:

- Forms shall not be removed until the minimum standing time was

elapsed

- Minimum standing time shall be determined in terms of the age or

compression strength of concrete Data and calculation sheets used in verifying safety and concrete test results in section 5 shall be submitted

to the Engineer for approval If the onset of strength is considered to have been delayed due to cold weather, the above shall be determined

by compression strength instead

- Supports of a cantilever beam, canopy with a large span, large-size

floor slab or an extremely large working load shall be kept for longer periods as required

- Supports shall not be re-shored Sheathing boards below floor slabs and

beams shall be removed after taking out supports

4.5 HEAD TREATMENT FOR FORM TIGHTENING PARTS

When there is no finish on a visible face after forms are removed, the heads of form-tightening parts shall be removed and a rustproof paint shall be applied Mortar filling shall be generally performed below the face For a thin finish such as paint coat, the mortar bed shall be flush with concrete surface

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CHAPTER 5 CONCRETE WORK

5.1 GENERAL

5.1.1 Scope

This Chapter shall apply to the following concrete construction work:

- Concrete types shall be normal weight concrete and lightweight

concrete However, this shall not apply to the section of light weight concrete in direct contact with the ground

- Concrete casting plan for sub-structure, super-structure

- Concrete should be ready-mixed concrete and mixed at site concrete

- Placement of concrete shall be performed using concrete pumps,

bucket chutes etc

5.1.2 Standard Design Strength

The standard design strength (F0) of concrete, indicated by the compressive strength at the age of 28 days, shall be shown on the structural drawings in the Design Documents

5.1.3 Classification of Ready Mixed Concrete

Kinds of ready mixed concrete shall conform to specify by the structural drawings in the Design Documents

Sequence of construction of building floor slab

5.2 CONCRETE CASTING PLAN

5.2.1 Sub-structure

Casting for each pilecap (foundation) in each group of every segment VINACONEX E&C uses concrete pumping truck for casting concrete to ensure the implementation is on schedule

Assembling of widen scaffold

Construction of formwork

Construction of reinforcement

Concrete works

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5.2.2 Super-structure

After the completion of rebar work and formwork, VINACONEX E&C uses concrete pumping truck with the 36m rod in height Casting concrete for each concrete frame

5.3 MATERIALS FOR NORMAL WEIGHT CONCRETE

- Aggregates shall be ordinary aggregate, while coarse aggregates shall

be gravel, crushed stone, blast furnace slag aggregates or a mixture of these Fine aggregate shall be sand and may contain crushed sand

- Quality of aggregates:

- Aggregates shall be of higher strength than hardened cement paste in

concrete, and shall be suitable for use in reinforced concrete

- Grading of aggregates shall be made by mixing suitable quantities of

fine and coarse grained materials

5.3.3 Water

Water shall not contain dangerous levels of impurity which may adversely affect concrete and/or reinforcing bars

5.3.4 Admixtures

Admixtures shall be of good quality suitable for reinforcing bars

5.4 MIX PROPORTION OF ORDINARY CONCRETE

5.4.1 General Conditions for Mix Proportion

The mix proportion of concrete shall provide the required strength, workability, uniformity and endurance

Design slump shall be the required slump plus the change anticipated after hardening of concrete

Design air content shall be the air content plus required air content for change anticipated after production, and the required air content shall be 4.50/vl Unit water volume shall be less than 185 kg/m3 in design mix proportion to be used Where unavoidable this may be less than 200kg/ m3 if approved by the Engineer

Minimum cement content shall be follow the design mix proportion

Water/cement ratio shall be less than 650/wt for the design mix proportion Admixture can be used for concrete The admixture shall conform to the following according to cement content, unless otherwise shown on the structural drawings and directed by the Engineer

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5.4.2 Approval for Design Mix Proportion

Prior to starting construction the Contractor shall be required to verify that design mix proportions at the concrete producing plant will produce the required strength, workability, uniformity endurance and other performance factors designated in this Section, based on the design mix proportion prepared

in accordance with Item (2) or (3), and also to obtain approval from the Engineer of the design mix proportion sheets

- Design mix proportion sheets of the concrete production plant shall

show materials used for production, basic data used in mix design and calculation sheets

- Design mix by production plant shall be similar to the mix of the

similar mix adjusted to compensate for the use of different materials

- In the case of other than item (2), trial mixing shall be carried out to

verify quality

- Trial mixing shall be performed in the presence of the Engineer until

design slump, design air content, and mix strength (including strength tests at the ages of 7 day and 28) are obtained

- Where unavoidable, mix strength may be estimated from the strength at

the age of 28 days based on the strength at the age of 7 days, using suitable data after obtaining approval from the Engineer

5.5 PRODUCTION, TRANSPORT AND PLACEMENT OF CONCRETE

5.5.1 General

Prior to the work, the following items shall be submitted in writing to the Engineer for approval :

- Method of concrete placement

- Forced feed capacity of concrete pump, layout and supporting method

for conveying pipe, procedures in the event of interruption of conveyance

- Procedures for concrete in the event that major anomaly arises

following forced feeding

- Where transport is not to be performed by concrete pump, a description

of equipment, performance etc

- Distribution of workers, auxiliary facilities or tools

- Machinery and tools shall be adjusted periodically prior to starting

work as well as during work

5.5.2 Production

Instructions to the manufacturing plant are indispensable for obtaining concrete with the quality stipulated in Section above

5.5.3 Process up until conveyance by Pressure Feeder or similar Machinery

Transport of concrete shall conform to the following :

- Preparation for placing concrete shall be carried out to enable concrete

to be poured within one hour and a half after the start of mixing

- Immediately before unloading concrete, rotate the truck agitator at high

speed to agitate the concrete and make it uniform

- Always carefully check the quality of concrete to be unloaded

5.5.4 Forced Feeding and Transport on Site

Forced feeding of concrete

Conveying pipes shall be held using walking boards on supporting bases, supporting bases, trestles, suspending hardware, etc No hazardous vibration

of conveying pipe shall be transmitted to concrete forms or reinforcing bars The size of the conveying pipe shall be determined in consideration of the following (Minimum nominal diameter of conveying pipe for the maximum size of coarse aggregates)

- Distance and height of forced feed, affect on concrete of forced feed,

difficulty of using forced feed, air temperature

- Volume of forced feed per unit time and maximum size of coarse

aggregates

The length of the flexible hose shall be less than 6m as a rule when the nominal size of the conveying pipe is less than 100mm For pipes over 100mm the hose shall be less than 5m except for pump vehicles with booms

The maximum horizontal transportable distance of the forced feed machine shall be more than the horizontal equivalent of the total piping distance plus a certain allowance

Prior to force feeding concrete, rich mortar shall be input in order to prevent change in concrete quality Prior to force feeding mortar the inner surface of the equipment should be wet

The following sections of forced feed concrete shall be discarded Good sections of forced feed mortar prior to the forced feed of concrete can be poured in concrete forms if scattered so that only a small quantity is present at any one place

- Concrete changes significantly during forced feed

- Altered portion of mortar stated in (5) first ejected

When using a sloped chute the following requirements shall be met:

- Section is U-shaped and made from steel or iron sheet

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- Slope is 4/10 to 7/10

- Funnel longer than 600mm used at chute outlet

When discharging concrete from high places longitudinal flexible chutes shall

be used

5.5.5 Placement

Prior to concrete placement, clean the area when concrete will be placed, remove miscellaneous objects, and spray water to moisten the sheathing boards and construction joints

If a rainfall that may affect the quality of concrete is predicted curing shall be performed When curing is not possible concrete shall not be poured

Placement shall be carried out mainly by (1) as stated below for ordinary story heights or, depending on the situation, (2) after obtaining approval from the Engineer

- Each story is divided into the portion below the beam and the portion

below the top of the floor slab Placement shall be varied so that each portion is horizontal

- When there is a portion from which a wall beam rises up the concrete

shall be placed in succession in accordance with the setting conditions

of floor slab concrete

- Concrete forms are to be strengthened to prevent deformation, and

concrete is to be placed on the floor slab one at a time, from the end to the whole

- Use (1) for wall and beam concrete placement

Parapet or eaves shall be poured as one body with the structure supporting it as

a rule

Do not pour concrete directly from the flexible hose to the column

When interruption to concrete placement is necessary, predetermine the pouring section and limit the interrupting time to one hour as a general rule Compaction of concrete shall be performed to all parts of the concrete form Normal allocation shall be at least two bar-type vibrators per concrete conveying pipeline system, and two or more vibrator-operating workers plus more than seven workers for tapping compaction

Floor slabs shall be compacted by tapping the surface with tamper after rough leveling but before concrete setting to prevent cracking due to settlement, and shall be made to level surface

5.5.6 Joints of Successive Pours

Joints of successive pours (construction joints) shall be horizontal or vertical and located near the center of the span for beams and floor slabs, or on top of the floor slab, wall beam or foundation for walls and girders

Partition plates shall be used for the joints of successive pours such that mortar, cement paste will not leak out Where the horizontal construction joint

is on the outer surface, it shall be made straight using driving rulers (baby

5.6 TESTING

5.6.1 General

This Section applies to the testing of concrete and concrete materials Some of the tests may be omitted if the concrete is light, or for smaller sections, if approved by the Engineer

Areas used for testing of materials shall comply with the following as far as possible:

- For cement and aggregates, the location of concrete production

- For normal weight concrete, location where unloading takes place on

site

- For lightweight aggregate concrete, immediately before placement at

the location where placement of concrete forms takes place on site 5.6.2 Material Tests

Material tests shall be conducted in accordance test reports shall be submitted

to the Engineer for approval In case of the following result, the Contractor shall consult with the Engineer for solution:

- Crushed sand and crushed stone designated as type B is found to be

un-harmful

- Immutable weight control is specified as the measure for restricting

kind B and alkali aggregate for crushed sand and crushed stone, and the total alkali in concrete exceeds 3.0kg/m3 without being judged un-harmful

5.6.3 General Rules for Strength Tests for Concrete

Number of test pieces and collection of test samples

The number of test pieces shall be three for each type of test: age days, age 28days, assessing time to remove forms, etc

Test samples shall be collected three times separately from dollies at suitable intervals for the purpose of preparing the test pieces required in (i)

Compression strength test shall conform to Test method for concrete compression strength

5.7 TROWEL FINISH FOR FLOOR CONCRETE

- Determine origin of reference height for each story

- Determine reference height for finishing work before pouring concrete

- Leveling with ruler :

- Maintain accurate height reference to either level or required gradient

- After pouring concrete, level roughly with a scoop or shovel and tamp

concrete with tamper until coarse aggregates sink below the surface

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Level the surface with a long straight board while accurately maintaining height in alignment with reference height using level or leveling string

- Elimination of irregularities in the middle After using the straight board

level the surface flat with wooden trowel

- Trowel finish:

- Rubbing with wooden trowel: After eliminating irregularities rub the

surface with wooden trowel, gauging the timing correctly with surface hardening

- Metal trowel finish:

After rubbing with wooden trowel, finish the surface smooth with metal trowel This finish work shall be performed before concrete has hardened too much so that the trowel is still possible

Do not spray water, cement or the like on the surface during finishing

In the case of trowel finishes use walking boards or stepping boards to avoid stepping directly on concrete surface

Take extra care at construction joints to avoid contaminating the finish surface

Finish smoothly with grinder after concrete sets in places where significant irregularities caused by trowel finishing are discovered 5.7.4 Curing

After surface finishing, perform the curing specified in Paragraph above Gauge timing in accordance with degree of setting of concrete Also in the case of Type A, provide curing and surface protection by covering with vinyl sheets or the like

When installing concrete forms for upper stories or transporting reinforcing bars, take special care not to damage the finished surfaces

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CHAPTER 6 ERECTING COMPONENTS

6.1 GENERAL CHARACTERISTIC OF EXECUTIAT THE SITE

- Traffic

- Construction plan

- Geological condition

- Ability of supplying electricity

- Ability of supplying water

6.1.1 General characteristic of project

Description of site organization

Site manager (take responsible under director of company) allots the work for engineers and working group under his management, co-operates with related companies to work Vice director takes responsible for supervisor the site under director’s instruction, however, separate with site manager to ensure the quality and meet schedule

Obligations, rights at the site

Site manager

- Representative of the company manages working at the site,

co-operates with main contractor, the owner to solve all the work in scope

of the project

- Degree: engineer

- Obligations and rights

- Take responsible under director and legislation for controlling

technique, quality, safety of project

- Arrange and manage the staff to study all the technical, quality,

material, technological requirements so as ensuring the quality of project

- Set up working method of project and all item relates to project Follow

exactly the working method which is approved by the director

- Tinspect regularly to find out the fault, therefore avoiding the bigger

problems

- Tcooperate and give a good condition for the owner’s supervisors, and

other supervisors to complete their duty

- Take responsible for gathering quality technical documents, preparing

documents for acceptant and handing over

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- Be well-understood all the instruction of the engineer, then divide the

work to the team’ member, as well as manage them to finish the work follow the design in time

- Inspect and assess the quality of team’s work, repair the faults and

report to engineer

- Refuse to use low quality material

- Right of propose commence and reward, discipline the team’s member

for their work

6.2 EXECUTED ORGANIZATION

6.2.1 Project introduction and working condition

Construction plan is large; locate in planning scheme of industrial park

Road for construct/ access route:

- Project characteristic: it is a rather large scale construction Access

route is convenient for transporting and gathering the elements

- Transportation of element is rather difficult because the project locates

far from the manufacturer

- Construction plan is large So it’s convenient for hoisting and erecting

elements by crane

- Electricity: the contractor asks the owner for supplying a nearest

electric box We will operate all electric equipments in the right procedure and safe as well as in efficient way

- Use and discharge water in the right way of presently regulation

6.2.2 Quantity of erecting work and general working method

List of necessary works

- Erect precast column

- Set up scaffold supported beam

- Erect precast beam

- Set up scaffold supported slab

- Erect precast slab

- Casting topping concrete

Quantity table of erecting typical precast slab

4 Concrete topping M3

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6.3 ORGANIZING AND WORKING METHOD

6.3.1 Organizing method

Characteristic of erecting procedure

Erecting method includes 2 procedures: unloading and erecting precast element These procedures need to be met the quality and technical requirements This results in the strength of the superstructure During erecting progress, there are many type of precast element, so the crane should be located at the most advantage location to erect as much as possible, so as reducing time for movement, setting up the crane It’s good to combine supplying, transporting and unloading suitably in order to reducing working time

Table of the greatest size and weight precast element

Item Type of

element

Length (m)

Width (m)

Height (m)

Choose working machinery

Choose working machinery for ground floor

- Base on total schedule of project

- Base on actual plan

- Base on the weight of precast element

- The contractor decides to chose the 50 ton crawl crane to unload and

erect the precast elements for meet schedule

- Erecting column, beam, and slab synchronously to minimize the

movement of crane in order to maximize working result

- It’s necessary to define suitable parameter for choosing the best crane

- Base on the farthest, highest position; weightiest element and the worst

position of crane to choose the best crane Labor force:

The contractor implements the work in cycled series All the workers need to pass the health checking for working in high positions Moreover, they need to

be fully equipped of safety facilities and trained for safe regulation:

- All the workers must be healthy, knowledge, skillful, experienced and

careful to work

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- All the workers must be trained for erecting procedure, working

method in each stage The engineers always supervise to ensure the worker working correctly

- All the workers must wear safe-bell when working in high position

- Labor force at the site

List of machineries and equipments

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equipments

Heavy-duty end cutting pliers

- Putting the high strength bolt through the holes on column

- Using anchor shackle to stick into hoist cable

- Using the wire to orientate columns in the specified direction design

- Lower slowly the column so that the starter bar fits the hole on bottom

of the column

- Anchoring the column by hard or soft turnbuckle

- Aligning the column

- Removing the hook, moving the crane to continue

- Alignment after erecting column:

- Using cable anchor to keep the column stable then proceed down crane

- Rectifying center axis of column coinciding with the structure’s one

- Ensuring level of column’s peak

- Turnbuckle adjustment to ensure the vertical of the column

- Using stucco sealing the columns to ensure no leak

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Before pouring grout into the vacuum column, these follow steps must be done:

- Cleaning the column foot

- Clearing blockages (if any) in the the holes need filling mortar

- Asking supervisors to inspect after erecting columns

- Conduct pouring grout

- When pouring mortar, only one hole is allowed to pour, then let the

grout free to fill other holes to avoid the air remaining in the hole that result in creating the pore

Before pouring non-shrink grout, surface of waiting hole and foot of column must be moisture Then pouring high strength non-shrink grout until the hole is full-filled Ensuring the grout tight grip on the foot of the column, closing up the space between columns’ foot and the surface slab, and no flowing out When pouring grout to note the following:

- To check the axis’s center, vertical before filling grout

- Ensuring to pour grout quickly so that reducing the quality of the

mortar’s cure

- When pouring grout to ensure it continued until full filled, avoid

pouring as many times that makes it dividing into many layers leading

to low quality

- After finishing work In dry season condition, it must be maintained

regularly 1 to 2 times per day within 3 days

- Because non-shrink grout is high strength, quick frozen So to

avoid spilling out, it should make a edge by mortar grade 75 or by wood If there is reason to pour into 2 times, amount of time between 2 times doesn’t exceed two hours apart First time, pouring full-filled the column’s foot up to approximately edge position, waiting the grout rather hard in surface then pouring second times to complete After 1-

2 days, using concrete to seal hole

Maintenance column joints:

- Column joints are wet using quick frozen, non-shrink high strength

grout After pouring, we pay special attention to the maintenance of joints as with conventional concrete:

- Avoid strong shock in the curing time

- Make sure the standard moisture of curing

- When the intensity reached > = 50% strength designed, dismantle the

entire anchored device

- After pouring grout a period of 24 hours, other stages are allowed

to proceed

- Tolerance after completion of temporary fixed:

- Deviation in foot column:  10mm

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- Deviation of vertical column’ peak:  6mm

- Bias of the overlapping beams level:  10mm

6.4.2 Erecting beam

When the column was erected hardly enough then proceed to install beams in the following order:

Prepare scaffolding to erect beams on top of the column

- Checking the size of the beam, marking the location of beam’s center

on the corbel, top column (or the binding beam – column location)

- Checking if the beam height above floor, it should be rectified Using

dedicated cable to anchor with the hook built on the beam

- When hoisting the girders, combining with using wire to locate the

beam in correct position

- Paying particular attention to avoiding collisions assembled beams to

columns and beams which are already installed

- Slowly lower beams to ensure starter bar placed into the column

- Calibrating beam’s center to coincide with the axis’s center, chocking

the corbel so as the column is vertical and the right height

- Cleaning dirt, watering contact surface at the top of the column

- Erecting formwork around the columns

- Pouring concrete when the around beams are installed

- Check the requirements to achieve the assembly tolerance index for the

- following:

Axis deviation beam:  10mm

Level of the beam is not vertical: 10mm

Bearing length deviation (direction of beam length):  15mm

Bearing width deviation (horizontal beam direction):  10mm

Bias on beam’s level as bearing on the floor: +5,-15mm 6.4.3 Erecting slab

The order of installation is similar to installation of beam:

When the girders were erected in place and ensured the correct procedures, technical regulations, then erecting the slab in the following order:

Checking the geometric dimensions of the slab

- Checking type of slab

- Using a special cable to hook into the hook on the floor

- Hoisting slab panel, combining with using wire to locate the slab in

correct position

- Aligning the top of slab panel follow the design

Handling reinforcement: this work was conducted by mechanical methods The steels are clean free of mud, oil, grease or rust before handling The contractor handles each type of reinforcement and numbering each type

to avoid confusion Reinforcement is handled in right shape and dimensions as designed Technical staffs of the contractor regularly inspect the processing of reinforcement

Erecting rebar: Rebar was erected in order and follow the design for each type of reinforcement When erecting rebar, the contractor must the following conditions:

- The installation of rebar must be correct in type and number of design

- The first part erection does not interfere with the erection of the

following sections

- To take measures to stabilize the position of rebar to not move during

the concrete pour

- Thickness of the concrete cover block is equal to the thickness of cover

concrete

- The corners of the reinforcement stirrup with the bearing steel columns

are firmly tied

- The rebar was lapped following design After completing

the installation of reinforcement and acceptance, erecting form work b) Formwork:

For erecting formwork, due to the construction includes only one floor, so the formwork is just erected when casting topping concrete of the slab The contractor chose to use timber formworks and steel braces when constructing When erecting formwork, these following requirements must be ensured:

- Formwork and bracing system are hard, stable enough, and easy to take

apart They also don’t cause difficulties for the poured concrete and concrete compaction

- Formwork assembled sealed, tight not to lose cement water when

pouring and compaction concrete, while protecting the newly poured concrete under the influence of weather

- Formwork assembles to ensure proper shape and size of the structure

- The struts which support the formwork are layout in reasonable of the

density to ensure stability of formwork during concrete pouring and compaction

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- After erecting, formwork is inspected at the site with participation of

the owner’s supervisor and contractor Content of inspection and acceptance include:

- The shape and size compared with the shape and size of designed

structure to cast concrete

- Location of structure to pour concrete

- The plane between the pair of formwork

- The tight fit of the formwork

- The details are in place

- Cleaning the inside formwork

- Structural supporting member, stiffness and stability of

the formwork system

After all relevant parties make a confirming minutes for acceptance, then carrying out casting concrete

Dismounting formwork when the concrete is strong enough to withstand the weight of the structure itself and the impact load of later constructed phase Dismounting formwork must be done carefully to avoid impacting the concrete’s strength

c) Casting concrete:

- The contractor use ready mixed concrete in construction Before using,

we submit investor the certificate of product quality, capacity mixers to approval

- Asking the owner’s supervisor to acceptance before casting concrete (if

pass the acceptance)

- The samples of concrete are taken at the site and

humidity maintained according to the TCVN 3105 - 1993 at the mixing plant The samples are taken by set, each set consists of 3 samples at the same time according to TCVN 3105-1993, size of sample block size 15x15x15 cm

- The concrete is casted by pouring concrete pump cars In the process of

pouring concrete, contractor must ensure the following requirements:

- Not to distort the position of reinforcement, formwork doesn’t be

deformed or movement, as well as ensure the thickness of cover concrete

- Concrete is poured into layers until complete a proper structure of stop

at construction joint

- Regularly inspect formwork systems, detect and timely treatment when

formwork is going to be bulge

- The contractor use vibrator, surface vibrator to compact concrete

following below requirements:

Time of concrete compaction at each position is enough to ensure concrete is compacted carefully When observing grout float to the

Concrete is inspected and accepted at the site following the current standards 6.4.4 Erecting Eaves

When the column has been erected hard enough and roof truss is already installed, then proceeding to erect eaves following these orders:

Preparing the scaffold to erect eaves into the column

- Checking the size of eaves, marking the location of eaves’ center on top

of the column

- Checking the bottom level of eaves and repairing if necessary Using

dedicated cable hook on a hook was built on eaves

- When hoisting the eaves, combining with using wire to locate the eaves

in correct position

- Paying particular attention to avoiding collisions assembled eaves to

columns and beams which are already installed

- Slowly lower eaves to ensure starter bar placed into the column

- Calibrating eaves’ center to coincide with the axis’s center, chocking

the top of column so as the beam is vertical and the right height

- Welding the angle bar to fix temporally the eaves before joining two

ends of eaves

- Cleaning dirt, watering contact surface at the top of the column

- Erecting formwork around casting place

- Pouring concrete to join two ends of eaves

Procedure of arranging precast elements

When components are transported to construct at the sites:

- Checking the dimensions, hole’s center, steel’s center, and

specifications of starter bar

- Checking surface of the product for non-porous, no cracks

- Preparing the plan: flat background, the ground must be compacted

well at position of placing components

- Laying according to regulations to ensure safe and non-affect the

structure The slab shouldn’t be laid 7 pieces in one stack, beams must

be laid according to the working direction of the beam, if beams are high >=500 mm, it should have special pallet

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6.5 GENERAL REGULATION

The training and guidelines on labor safety is the responsibility of unit which manages the worker:

- When designing and constructing buildings must comply with

the current regulations and standards related to labor safety, environmental sanitation and fire prevention

- Don’t construct until having enough document of organizational

design and construction design In that document must be measures to ensure labor safety, environmental sanitation, and fire prevention

- Board of management: director, site manager, team leaders, heads

of departments, labor safety staff must follow full and proper liability regime for the labor safety under current regulations

- Responsibility for the implementation of safety requirements when

using machinery (equipment, construction equipment), including the means of team protection and personal protection for those who

- On a construction at the site, if there are some co-constructions units,

the main contractor B must coordinate with other construction units

to work out measures to ensure labor safety In area where there are many construction units must set up the joint committee to monitor safety at the site

- When construction at the site of a facility is operating, the director

of the construction units and manager of facility must be together to set out measures of ensuring safety The parties must make full and timely general safety measures within their own responsibility

- Workers at the construction at the site must have all the following

criteria:

Age prescribed by the state for each job

Having a certificate of health as required by medical organization Annual health checks must be at least once In case of working

on high, heat, dust, harmful position, workers must take a private health check following the health regulations It doesn’t allow arranging in pregnant women, with children under 9 months, people with heart disease, hearing, and eyesight problems children under 18 years of age to do the above works

Having the certificate of training and satisfactory inspection of work safety in accordance with each job by the validation of the director

A fully equipped vehicle for personal protection in accordance with the working conditions under the regulations

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CHAPTER 7 STRUCTURAL STEEL WORK

7.1 GENERAL

7.1.1 Scope of Work

The Contractor shall submit the following items to the Engineer for approval

of the steel fabrication factory which the Contractor intends to employ for assembly of the structural steel

- Capacity and scale

- Past record

- Organization

- Mechanical facilities

7.1.2 Quality Control Standards

Quality control and inspection standards for construction in the steel factory and on-site shall be approved by Engineer in advance

Products to be used shall be tested and passed by in-house inspections in the steel fabricating factory, and inspection records submitted to the Engineer However for minor work, the submission of inspection reports may be omitted

if approved by the Engineer

7.1.3 Construction Management Engineer

The construction management engineer shall be a steel fabrication management engineer

The steel fabrication management engineer shall have knowledge and skills in the field of steel fabrication management

The steel fabrication management engineer shall be involved in steel fabrication relevant to the construction work, and shall strive to improve quality

7.2 MATERIALS REQUIREMENTS

7.2.1 Steel

Steel shall conform to the Technical Specification

7.2.2 High Strength Bolts

High strength bolts shall be "high strength bolts" or "torque shear type high strength bolts"

High strength bolts:

- Sets of bolts, nuts and plain washers shall be standard products (sets of

high strength hexagon bolts, hexagon nuts and plain washers for friction grip joints)

- Sets shall be Type 2 (F10T), and types based on torque coefficient

values shall be suitable for construction work

Testing method shall correspond to the materials specified

For steel plates subjected to tensile force in plate thickness direction, the test (Grade classification and decision criteria for architectural steel plates using ultrasonic flaw detector) shall be conducted during production

For torque shear- type high strength bolts, the production control method and the results of quality control tests for the products shall be submitted to the Engineer for approval For minor work this may be omitted if approved by the Engineer

For principal welding materials other than standard products, data and documentation verifying quality level sufficient for welding shall be submitted

to Engineer for approval For minor and/or low-volume work this may be omitted if approved by the Engineer

7.3 GENERAL SHOP DRAWINGS

- Standard drawing for welding work

Prepare full scale drawings (including templates and rulers) and for inspection and approval by Engineer If automatic processing equipment (full-scale, marking-off, cutting and drilling) is used then this may be omitted if approved

by Engineer

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7.3.2 Verification of Standard measuring Tape

Standard measuring tape shall be Class 1 of Steel measuring tape The standard

Measuring tape for steel fabrication shall be compared with the standard measuring tape for the

Construction site to verify that discrepancies will not adversely affect construction work

The cutting surface of raw materials shall be normal to the axis of the member except when specified otherwise

Cutting shall be done using automatic gas cutting Where manual gas cutting

is unavoidable the material shall be carefully shaped with grinder to correct the shape and dimension

Shearing of steel plate is permitted for thickness of less than 13mm No shear edge shall be permitted at the free ends and welded joints of principal members

Any dangerous projections, recessed portions, burrs or notches on the cutting surface shall be corrected or removed

Bending shall be performed at normal temperature or by hot process The hot process shall be performed in red heat state without sudden cooling

7.3.6 Correction of Distortions

Distortion in raw materials or assembled members shall be corrected in respective processes

Installation of Components for Temporary Works

Approval shall be obtained from the Engineer before installing auxiliary members or making