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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 PART PLANNING AND DESIGN FOR ROADS AND BRIDGES PLANNING AND DESIGN FOR BRIDGES WARM-UP A B a Match the names of the bridge (1-4) to the pictures (A-D) Tower Bridge of London, England Golden Gate Bridge, San Francisco, American Sydney Harbor Bridge, Australia Akashi-Kaikyo Bridge, Japan C b What you know about these bridges? D VOCABULARY BUILDING Types of Bridges Look at the following pictures, which bridges you know are of these kinds? Beam Bridge Basic Beam Bridge Actual 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 Arch Bridge Basic Arch Bridge Actual 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 Suspension Bridge Basic Suspension Bridge Actual Suspension Bridge 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 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 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 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 Grade Separation 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 Interchange Bridge Overcrossing 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 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 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 Types bridges and applicable span length Highway Bridges (2003) in theofUnited 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) Steel arch 50–550 m (164–1804 ft) Quebec, Canada; 549 m (1801 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) a Read the text and circle the best answer A, B, or C 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 What is the first step in bridge design is a Theoretical analysis b Consideration of the surrounding landscape c Conceptual design 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 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) The final process in bridge design involves a computer models, which use appropriate material properties b preparation of construction drawings and specifications c member discretization, boundary conditions, and loads b Read the text again and answer questions What is a highway bridge? Which structures are considered highways bridges? What materials are highway bridges made of? How long is the longest steel truss bridge? What are the two standards in bridge design in the United States? c Without looking at the text, match the terms with the definitions is the group of ramps and structures providing Overhead Underpass is a structure separating into two state highways Overcrossing is a structure carrying a highway over a railroad Undercrossing Interchange Viaduct Separation Connector ramp connections for traffic between intersecting highways is an elevated structure carrying a highway over streets, railroads, or other features is a structure providing passage of a county road or a city street under a state highway is a structure providing passage of a highway under a railroad is a structure carrying a county road or a city street over a state highway is a structure connecting intersecting highways and roads 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 b In pairs discuss the Golden Gate Bridge using the note above VOCABULARY CROSSWORD PUZZLE ACROSS DOWN structure carrying the roadway above the substructure intermediate support for bridges bridge supported by catenary cables distance/interval between pier supports provides connection to intersecting highways type of continuous bridge over valley or mountain structure supporting bridge ends WRITING a Write a short paragraph (about 250 words) about a famous bridge in the world - Where is the bridge? 10 - 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? 11 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 12 [...]... loads, surrounding geographical features, width requirements, clearance requirement below the bridge, transportation of construction materials, erection procedures, and construction cost and duration 12