Bài giảng Tiếng Anh Chuyên ngành giao thông Đại học Công Nghệ GTVT (UTT)Unit 1part 2

Unit 1 PLANNING AND DESIGN FOR ROADS AND BRIDGES PART 2 PLANNING AND DESIGN FOR BRIDGES Overhead   is the group of ramps and structures providing connections for traffic between intersecting highways Underpass   is a structure separating into two state highways. Overcrossing   is a structure carrying a highway over a railroad. Undercrossing   is an elevated structure carrying a highway over streets, railroads, or other features. Separation   is a structure providing passage of a county road or a city street under a state highway. Connector ramp   is a structure providing passage of a highway under a railroad. Interchange   is a structure carrying a county road or a city street over a state highway. Viaduct   is a structure connecting intersecting highways and roads.

Unit 1 PLANNING AND DESIGN FOR ROADS AND BRIDGES

1 WARM-UP

a Match the names of the bridge (1-4) to the

pictures (A-D)

1 Tower Bridge of London, England

2 Golden Gate Bridge, San Francisco, American

3 Sydney Harbor Bridge, Australia

4 Akashi-Kaikyo Bridge, Japan

b What do you know about these bridges?

A

B

C

D

2 VOCABULARY BUILDING

Types of Bridges

Look at the following pictures, which bridges do you know are of these kinds?

1 Beam Bridge

A beam or "girder" bridge is the simplest and most inexpensive kind of bridge In its most basic form, a beam bridge consists of a horizontal beam that is supported at each end by piers The weight of the beam pushes straight down on the piers

2 Arch Bridge

Arch bridges are one of the oldest types of bridges and have great natural strength Instead of pushing straight down, the weight of an arch bridge is carried outward along the curve of the arch to the supports at each end These supports, called the abutments, carry the load and keep the ends of the bridge from spreading out

3 Suspension Bridge

Basic Suspension Bridge Actual Suspension Bridge

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Aesthetic, light, and strong, suspension bridges can span distances from 2,000 to 7,000 feet - far longer than any other kind of bridge They also tend to be the most expensive to build

4 Cable-stayed Bridge

Basic Suspension Bridge Actual Suspension Bridge

Cable-stayed bridges may look similar to suspensions bridges both have roadways that hang from cables and both have towers The difference lies in how the cables are connected to the towers In suspension bridges, the cables ride freely across the towers, transmitting the load to the anchorages at either end In cable-stayed bridges, the cables are attached to the towers, which alone bear the load

5 Truss Bridge

Basic Truss Bridge

Actual Truss Bridge

A truss bridge is a bridge that has a load bearing structure supported by trusses Trusses are triangle shaped units, connected at joints Truss bridges are among the oldest in modern bridges

3 READING

DESIGN OF HIGHWAY

BRIDGES

A highway bridge is a structure that crosses

over a body of water, traffic, or other

obstruction, permitting the smooth and safe

passage of vehicles In highway

transportation systems, the term “bridge” is

usually reserved for structures over bodies

of water However, many other structures

are generally considered highway bridges An

overhead is a structure carrying a highway

over a railroad, and an underpass is a

structure providing passage of a highway

under a railroad An overcrossing is a

structure carrying a county road or a city

street over a state highway, and an

undercrossing is a structure providing

passage of a county road or a city street

under a state highway

A separation is a structure separating into two state highways A connector ramp is a structure connecting intersecting highways and roads An interchange is the group of ramps and structures providing connections for traffic between intersecting highways A viaduct is an elevated structure carrying a highway over streets, railroads, or other features

Highway bridges can be made of steel, concrete, timber, stone, metal alloys, or advanced composite materials, and may have different structural systems such as girder (beam), truss, arch, cable-stayed, and suspension

Design

Bridge design is a combination of art and science Conceptual design is usually the first step Before any theoretical analysis and detailed design process, the designers visualize the bridge in order to determine its function and performance.

Bridge Overcrossing

Grade Separation

Interchange

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The conceptual design process includes selection of bridge systems, materials,

proportions, dimensions, foundations, aesthetics, and consideration of the

surrounding landscape and environment A bridge may be straight or horizontally

curved, or have skewed supports The width of a highway bridge is determined by

the number and width of the traffic lanes and the shoulder or sidewalk width, and

is typically the same dimension as the approaching highway.

The selection of bridge type is influenced by many factors such as span length,

site geology and foundation requirements, design loads, surrounding geographical

features, width requirements, clearance requirement below the bridge,

transportation of construction materials, erection procedures, and construction

cost and duration The table shows the span lengths appropriate for various bridge

types A bridge is required to fulfil its function as a thoroughfare while blending

and harmonizing with its surroundings.

The final design process involves structural analysis, member and detail design,

and preparation of construction drawings and specifications Structural analysis

commonly involves computer models, which use appropriate material properties,

member discretization, boundary conditions, and loads

Members and connections joints are proportioned to carry all possible loads

(permanent loads, vehicular live loads, wind loads, and earthquake loads), combined

and factored in accordance with the requirements of applicable design standards

and codes Two standards are the American Association of State Highway and

Transportation Officials Load and Resistance Factor Design (AASHTO-LRFD)

Bridge Design Specifications (2004) and AASHTO Standard Specifications for

Highway Bridges (2003) in the United States.

Bridge type Applicable span range length Leading bridge and span length

Prestressed

concrete girder 10–300 m (33–984 ft) Stolmasundet, Norway; 301 m (988 ft) Steel I/box girder 15–376 m (49–1234 ft) Sfalassa Bridge, Italy; 376 m

(1234 ft) Steel truss 40–550 m (131–1804 ft) Quebec, Canada; 549 m (1801

ft) Steel arch 50–550 m (164–1804 ft) Shanghai Lupu, China; 550 m

(1804 ft) Concrete arch 40–425 m (131–1394 ft) Wanxian, China; 425 m (1394 ft)

[steel-tube-filled concrete] Cable-stayed 110–1100 m (361–3610 ft) Sutong, China; 1088 m (3570 ft) Suspension 150–2000 m (492–656 ft) Akaski-Kaikyo, Japan; 1991 m

(6532 ft)

Types of bridges and applicable span length

a Read the text and circle the best answer A, B, or C

1 An overcrossing is a structure

a carrying a county road or city street over a state highway

b carrying a highway over a railroad

c providing connections for traffic between intersecting highways

2 What is the first step in bridge design is

a Theoretical analysis

b Consideration of the surrounding landscape

c Conceptual design

3 The width of a highway bridge is

a determined by the length and width of the traffic lanes

b not determined by the shoulder or sidewalk width

c the same dimension as the approaching highway

4 Which suspension bridge has the longest span?

a Sfalassa Bridge, Italy; 376 m (1234 ft)

b Shanghai Lupu, China; 550 m (1804 ft)

c Akaski-Kaikyo, Japan; 1991 m (6532 ft)

5 The final process in bridge design involves

a computer models, which use appropriate material properties

b preparation of construction drawings and specifications

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c member discretization, boundary conditions, and loads

b Read the text again and answer questions

1 What is a highway bridge?

2 Which structures are considered highways bridges?

3 What materials are highway bridges made of?

4 How long is the longest steel truss bridge?

5 What are the two standards in bridge design in the United States?

c Without looking at the text, match the terms with the definitions

Overhead   is the group of ramps and structures providing

connections for traffic between intersecting highways

Underpass   is a structure separating into two state highways

Overcrossing   is a structure carrying a highway over a railroad

Undercrossing   is an elevated structure carrying a highway over streets,

railroads, or other features

Separation   is a structure providing passage of a county road or a

city street under a state highway

Connector

is a structure providing passage of a highway under a railroad

Interchange   is a structure carrying a county road or a city street over

a state highway

Viaduct   is a structure connecting intersecting highways and

roads

4 LISTENING AND SPEAKING

Golden Gate

Bridge

a Listen and complete the following note

GOLDEN GATE BRIDGE

- Has the longest (1) in the world

- Suspended road: (2) long

- (3) the San Francisco Bay to Pacific Ocean

- The project took (4) to complete

- The bridge: (5) long, (6) wide

- Two large cables pass over the top of the bridge’s (7) _

- The towers stand (8) above the water and

(9) above the road

- Each cables holds (10) strands of wire

GOLDEN GATE BRIDGE

- Has the longest (1) in the world

- Suspended road: (2) long

- (3) the San Francisco Bay to Pacific Ocean

- The project took (4) to complete

- The bridge: (5) long, (6) wide

- Two large cables pass over the top of the bridge’s (7) _

- The towers stand (8) above the water and

(9) above the road

- Each cables holds (10) strands of wire

b In pairs discuss the Golden Gate Bridge using the note above

5 VOCABULARY

1 structure carrying the roadway above

the substructure

1 bridge supported by catenary cables

2 intermediate support for bridges 3 provides connection to intersecting

highways

4 distance/interval between pier supports 5 type of continuous bridge over valley

or mountain

6 structure supporting bridge ends

6 WRITING

a Write a short paragraph (about 250 words) about a famous bridge in the world.

- Where is the bridge?

CROSSWORD PUZZLE

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- When did the construction begin? How long did it take to construct the bridge?

- Why was the bridge constructed?

- What type of bridge is it?

- How long/ How wide is the bridge?

- Why is special about the bridge?

b Translate the following passage into Vietnamese:

Bridge design is a combination of art and science Conceptual design is usually the first step Before any theoretical analysis and detailed design process, the designers visualize the bridge in order to determine its function and performance The conceptual design process includes selection of bridge systems, materials, proportions, dimensions, foundations, aesthetics, and consideration of the surrounding landscape and environment A bridge may be straight or horizontally curved, or have skewed supports The width of a highway bridge is determined by the number and width of the traffic lanes and the shoulder or sidewalk width, and is typically the same dimension as the approaching highway.

The selection of bridge type is influenced by many factors such as span length, site geology and foundation requirements, design loads, surrounding geographical features, width requirements, clearance requirement below the bridge, transportation

of construction materials, erection procedures, and construction cost and duration

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