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Structrural steel is from Vietnam, JIS G316, SM 41, SM 50, SM 50Y, SM 53. Standard.

Structrural steel is from Vietnam, JIS G316, SM 41, SM 50, SM 50Y, SM 53. Standard.

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Additional, Contractor carry out investigate electric, water,

telecommunication cable underground and traffic road,

house…on the plan to make a method to remove,

dismantle or select a suitable execution method, ensure to

the most economize. and cooperate closely with supervise

consultant or sign a contact with water supply, electric

underground cable system, telecommunication company

to be early determine underground systems in site zone,

then giving a method to solve on time.

2. Treat to irresistible situation

In during excavation and execution process, although

investigate carefully but it will be happened some

irresistible situation as follow:

a. Natural disastrous ( rain, storm, flood, fire...)

Rainstorm, flood: Contractor make a plan to establish a

board specialize to prevent storm and flood with functions

are always observe weather and pre-training situations

which are able to occur. If raining heavy all works at site

will be stopped and finding urgent and on time method

treatments. All execution equipment must move to safety

place. Structures that are half-done has to braced,

covered to ensure safety.

Contractor also contact closely with Local storm-flood

preventing board to cooperate in actions as well as obey all

requirements of board in other level of flood and storm.

b. Bomb & mine

Checking bomb and mine is not in scope of work of C3, but if

in during construction process found out bomb or mine..., we

will inform to Owner, Main-Contractor and other functional

organization at one, to evacuate every people, equipment

away quickly, avoiding far from dangerous place. using hard

fence to close that place and marking by flag, warning

board, appoint people guarding 24/24h until hand over to

functional organization.

Only carry out execution when mine or bomb have been

treated absolutely safety.

c/ Sand in mud status:



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When executing if occur mud-sand phenomenon,

Contractor will halt execution at one, and applying

emergency methods to limit of bad result, then inform

Owner, Main-Contractor, and Contractor put forward solution

method as follow:

- Stop excavation, fill back to limit damages

- Inform to Owner and Main-contractor.

- Considering and prevent or change stream flow

- Using bamboo pile (steel pile) to separate the mudsand zone with other else.

- Continuous excavating foundation (more deeply than

designing are about 300-500mm), using Geotextile to

spread over then fill on by stones, gravel for fixing,

beside that has to use a pump with high capacity to

pump water out of foundation pit. Mobilize

manpower, equipment, materials to execute quickly

and finish step by step.

- Needle-filter-well method can also be used to prevent

from sand silting phenomenon, this method is very

effective, however, it's high price so depending on

case, conditions that applying to be reasonable

d. Antiques and relics of history

During construction process, if appearing antiques or

historical relics, Contractor halt execution at once, inform to

Owner, Main-Contractor and other functional organization.

using hard fence to close that place and marking by flag,

warning board, appoint people guarding 24/24h until hand

over to functional organization.

e. Electric, telecommunication, water supply system…

During construction process, if appearing Electric,

telecommunication, water supply system, Contractor halt

execution at once, inform to Owner, Main-Contractor and

other functional organization. using hard fence to close that

place and marking by flag, warning board, appoint people

guarding 24/24h until hand over to functional organization.

3. Locating canal line

Base on documents of Main-Contractor, border-line of Owner

which has been handed over, Contractor will carry out

survey, locate and show the line of canal. Maintain landmark



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by placing concrete outside scope of building (Note that, the

place of putting landmark must be few means moving on

with intending to prevent from hitting of means coming and

going there). The centers of landmark will be determine

correctly by Theodolite and it must be intersecting points of

center lines. then this central point will be expanded to more

4 points which have 2m distance far from central points with

4 directions. This 4 points will be used for testing and

checking in whole time of construction process.

3. Inspection and as-built drawings.



B- execution statement

I. General

Cause of almost of works will be executed in/on water so

depending much on weather, underground water level of

specified points, zone.

In VietNam the rainy season is from June to August (mainly

on July). and other left is dry season, this season is quite

good conditions for execution

II. Execution statement of C3 package

II.1 General

According to Contractor' points of view, C3 package is

divided into 3 independent line (section) and 2 works as

follow:

- Line 1: This section is reinforced by stone masonry

on slope, it is lied between pump station and Uong

bi bridge No2.

- Line 2: This section is not reinforced slope but there

are 2 coffer dams run along side, It's lied between

Uong bi bridge No2 and Uong bi bridge No1.

- Line 3 : This section is not reinforced or banking

cofferdam. It's lied between Uong bi bridge No1 and

Intake bay.

- Work 1: Intake bay and trash & log boom, revetment

- Work 2: Swing wall of pump station.

With above zone definitions depend on characteristic of

engineering requirement, as well as method statement.

Contractor will carry out work as follow steps:

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II.1.1. Line 1: execution statement

will have a independent team take responsibility of execution

this section. All execution equipment and material will be

mobilized to Uong bi bridge No3 by existing road, then

carrying out execute expanding follow two directions. Step of

execution will be followed:

a. Step of excavation and banking cofferdam :

- Water in this zone will be discharged through a culvert to

Uong bi river

- Then using excavator, Crawler tire run along line to

excavate all mud layer and organic layer on the topsoil,

one part of excavated soil will be used to bank a small

temporary dyke for execution and other left will be

transported to outside by special truck. However, to have

starting point for Excavator and truck operate, need to

make wooden raft and temporary road for them standing

on.

- After mud layer excavated and removed, under layer is

2b, with purpose reuse this layer. We will continuos use

excavator and truck to exploit all 2b layer then gathering

to a specified ground for drying up, this quantity will be

use to bank cofferdam of another place, this layer can be

exploit from 6-6 section to 11-11 section with quantity is

about 135 350 m3. to keep drying for excavating need a

high power pump to prevent water coming.

- Layer next is 2d (sand), with this layer is also for used

later so when exploit 2b layer finish, we shall pump water

in canal line then using a dredger to suck sand from 2d

down to bottom of canal that sand will be gather to a

ground for reuse late

The section of canal after executed by Dreger is not

correctly as design so it must use a excavator on a barge

for repairing slope in accordance with design.



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b. Structures and execution

statement of canal

section reiforced

The standard for selecting canal section in this line is trying

reuse excavated soil, however, it must has structural

solution to ensure the dam stable and economize.

Structural solution and execution method for banks &

cofferdam as follow:

Excavate all weathered layer (mainly is 2a layer), this one

will be move to beside cofferdam,

Core of cofferdam will be filled by sand(2d), right and left

slope filled by clay (2b) to bar absorbent water with slope

factor is 3

We have calculated for absorb stably and slip stably for dyke

section by Geo-slope (Seep/w vµ Slope/w) program giving

absorbent gradient of lower section is 0.3, slip factor

calculated by Bishop, Kminmin=1.924.

The inner slope will be protected by PDTAC-M(Precastconcrete slope), outside slope will be seeded.

c. Step of slope reinforcement.

Line 1 is located in Uong bi town, so this part will be

reinforced by precast-concrete to make landscaping more

beautiful and cleaning, and prevent absorbent flow will not

roll sand with to lead blow off canal dyke, hereafter we will

show some reinforcement method of canal dyke.

* Stone masonry

This method in "request for quotation" documents in

previous period has been studied. From 9-9 to 11-11 section,

slope and canal bottom go through clay layer 2b so pumping

dry foundation pit to mason tone for protecting slope, but

from 1-1 to 9-9 section, slope and canal bottom go through

sand layer 2d and 2c so making foundation pit dry for stone

masonry is not easy work. So to execute this part need use

needle-filter-well

pumping

continuously

to

down

underground water level under bottom of canal, in the same

time must decrease absorbent water output, thus around pit

have to use steel pile to close this zone. Moreover the water

speed in canal is very low and go through weak soil, the

consolidation of canal during operating. At that time need to

dredge canal bottom, this work only can carry out by



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machine in about 20m central line of canal to avoid untablize

stone masonry at foot of slope .

* Precast-concrete carpet PDTac-M solution

Description

- PDTAC-M carpet is a kind concrete carpet that automatic

chocking with using a steel net, this one used to protect

for building with flooded bank, they are precast

reinforcement concrete, front surface is hexagonal in

shape, behind surface there are 3 automatic chocking

foots which is hooked, fixed on available steel net. Carpet

pices joined nearly with automatic link in 3 directions and

defending voids to prevent absorbent water flow in bank

running out that damage to stability of slope.

- With this structure, steel net act as buffer float to against

settlement, distribute load regularly of carpet on weak

soil, limit settlement phenomenon on some points of

concrete carpet and 4 edges of one mesh set up a border

to restrain the contact among carpet tiles, the void among

carpet tiles is small, regular enough to form joints which

restrain minimize the bending force on carpet tile, and

stretch force in steel net.

- P§TAC- M precast concrete carpet there are 2 parts: Carpet

net is knitted by steel d6-d8mm to make Sin in shape,

with length from 10-80m, 2.6-3.2m width, around by

border and inner is divided by steel d12-d16mm, then

putting carpet tiles on to make a continuos carpet.

- Concrete carpet is able to up 10-80m length or longer, at

present it is able to cover all slope. the area of carpet can

be changed depending on design, and able to execute 4

carpets about 800m2 per day.

- with flat surface will be easy for running water, make

more beautiful landscaping, environment, Behind surface

is a foot system which is fixed in slope foundation that will

make strong ability in nonslip of carpet tile.

- Carpet is constructed with steel float to against settlement

and could execute in water easy by crane on float, this

automatic-concrete carpet enough stability in long term



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Structrural steel is from Vietnam, JIS G316, SM 41, SM 50, SM 50Y, SM 53. Standard.

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