Hanoi – Hochiminh city railway line Do Vang Bridge’s construction bridges safety improvement project technology of beam casted on scaffolding

CHAPTER I: GENERALI. GENERAL DESCRIPTION

Do Vang bridge at Km432+420 in the construction package CP1C is one of nine

construction packages of Ha Noi – Ho Chi Minh city railway line bridges safety

improvement project.

Do Vang bridge is over Rao Nay River on Kim Hoa commune, Tuyen Hoa District,

Quang Binh Province. The bridge has 4 prestressed-concrete spans and 2 steel truss

spans, total length of bridge is 230.4m. The length of steel truss is long enough to meet

navigable clearance requirement and create least impact to the natural flow.

II. NATURAL CONDITIONS OF BRIDGE CONSTRUCTION AREA

1. Topographic conditions

The topographic at the construction site for the Do Vang Bridge, a bank river is

mountain slope with small grade and other bank river is relative flat ground with rice –

field, fram produce, thicket.

In general, the area is relatively convenient for transport materials during

construction process.

2. Hydrological conditions

Rao Nay River belongs to Gianh river system, has characteristics of Rivers in Central

Area that be short and sloping

The estimated water level for construction is H= 0.4m.

3. Climatic, meteorological conditions

Rainfall

The climate at Quang Binh and surroundings is affected by Middle Zone climate. It

comprises of two evident seasons: dry season from December to the August of the next

year, water level of the river lowers that often lead to drought. Raining season lasts from

September to December. The rainfall focusses in this season and causes to flood.

+ Average annual rainfall : 2,066mm

+ Daily maximum rainfall : 332 mm

Wind and Typhoon

+ The main wind direction in summer : East wind (Apr to Sept)

+ Average wind speed : 3.3 m/s – 4 m/s

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Hanoi – Hochiminh city railway line Do Vang Bridge’s construction bridges safety improvement project technology of beam casted on scaffolding

+ The main wind direction in winter : North and Northwest wind (Oct to

March)

+ Maximum wind speed : 20 - 25 m/s

Air temperature

The temperature is quite hight, hottest in summer (from Apr to Sept), coldest in

January.

+ Average annual temperature : 257

+ Average maximum temperature : 299

+ Average minimum temperature : 229

+ Absolute maximum temperature : 409

+ Absolute minimum temperature : 92

+ Temperature amplitude in contiuous months of a year and in continuous days is

not great, about 5 8C.

4. Geological conditions

The result of investigation drilling at bored hole shows that geology of the main

bridge area is divided into the following layers:

- Layer 1a: Poorly-Plastic clay (CL) is white gray with low compressibility.

- Layer 1b: Dusty clay (ML-CL) is brown gray, black spot with low compressibility.

- Layer 2: Poorly- plastic clay (CL) is yellow gray or black gray, white spot with low.

- Layer 3: Medium weathered, cracked granite with white gray, black spot, hardness

grade of VII-VIII, TCR=71%, RQD=62%.

- Layer 4: Medium weathered, cracked granite is gray, white spot, TCR=85%,

RQD=70%.

III. SCOPE AND APPLICABLE SPECIFICATION

1. Scope

Scope of project: permanently design by reinforced concrete and prestressed

reinforced concrete.

Using reinforcement concrete for construction 5 piers and 2 abutments on the bed-

rock and the pile cap with diameter D= 1.2-1.5m, length 7.5m-13m.

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Hanoi – Hochiminh city railway line Do Vang Bridge’s construction bridges safety improvement project technology of beam casted on scaffolding

The span structure is 4 span prestressed reinforcement concrete and 2 span steel truss,

span structure layout is 2x24.4m+2x66.4m+2x24.4m.

+ Length of bridge (distance of 2 center line of abutment) is 230.4m.

Design load:

+ Load T-15D, Pedestrian load 30x10-3 MPa in accordance with bridge design

standards No. 22 TCN 272-05.

2. Applicable standard for establishment construction technology.

Approved technical design and construction design.

Specification of Project

TCVN5439:1991 “Cement”

TCVN 2682:1989 “Portland cement”

TCVN 1770:1986 “Construction sand”

TCVN 1771:1987 “Ballast, stone use for construction”

TCVN 1772:1987 “The method of determines content of stone contaminant”

TCVN 4732:1989 “Construction devitrified stone”

TCXD127:1985 “Direction for use fine sand in concrete and cement”

TCVN 4314:1986 “Construction cement”

22TCN60-84 “Cement concrete”

TCVN 4506:1987 “Water uses for concrete”

TCVN 5440:1995 “Check and stability assessment of concrete”

TCVN 5592:1991 “Heavy concrete. Moist nature curing demand”

TCVN 6025:1995 “Grade division for compressive strength”

TCVN 5726:1993 “The method of prism strength definition and elasticity modulus“

TCVN171:1989 “The nondestructive method uses untrasonic machine and rebound

hammer for compressive strength definition”

TCVN 3106:1993 “The method of slump of concrete definition”

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Hanoi – Hochiminh city railway line Do Vang Bridge’s construction bridges safety improvement project technology of beam casted on scaffolding

TCVN 3118:1993 “The check method of concrete strength development”

TCXD 305:2004 “Mass concrete”

TCXD173:1989 “Plastic agent KDT2 for cement and construction concrete”

TCVN 3101:1979 “Cold- draw cacbonaceous steel wire for reinforcement”

TCVN 1651:1985 “Hot- rolling reinforcement”

TCVN 5709:1993 “Hot- rolling cacbonaceous steel for construction”

TCVN 6052:1995 “Iron scaffolding”

TCN 22- 272 - 05 “Specification for bridge design”

TCN 22- 247 – 98 “Work execution and acceptance regulations”

TCN 22-288-02 “Steel bridge and structure” .

Ability for mobilization materials, equipments of contractor

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