introduction to infrastructure : an introduction to civil and environmental engineering
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Introduction to Infrastructure : An Introduction to Civil and Environmental Engineering. Chapter 4: Transportation Infrastructure. Overview. Roads Mass Transit Waterways Tunnels ASCE Grades. Roads. Roads: Categories. Roads: Street Design. Crowning - PowerPoint PPT PresentationTRANSCRIPT
INTRODUCTION TO INFRASTRUCTURE:AN INTRODUCTION TO CIVIL ANDENVIRONMENTAL ENGINEERING
Chapter 4: Transportation Infrastructure
Overview
Roads
Mass Transit
Waterways
Tunnels
ASCE Grades
Roads
Roads: Categories
Roads: Street Design Crowning
Streets are constructed with a side slope, usually 2% (2 inches per 100 inches).
Prevents accumulation of water and Ice
Roads: Street Design Cross Section
A vertical “slice” of the street
Roads: Street Design Vertical alignment
Side-view or profile view of the road.
Roads: Street Design
Horizontal alignment Plan view of the road
Roads: Construction Material
Asphalt vs. Concrete
Granular Subgrade
Curves Must not be too
tight for vehicle speed
Roads: Intersections Design depends on vehicles
Intersections
Interchanges
Roundabouts
Roads: Intersections Conflict Points
Vehicle paths diverge, merge, or cross Typical intersection has 32
Mass Transit
Mass Transit Includes buses, trolleys, ferries, and rail
Only 5% of Americans use mass transit
Decrease in ridership decreases revenue
Decrease in revenue creates problems in sustaining the systems
Mass Transit: Rail 3 types of transit rail
Light Rail Low speed street cars and trams (Houston
Metro) Heavy Rail
Higher speed, higher volume (NY Subway) Commuter Rail
High speed, high volume rail between adjacent cities.
Rail: Shanghai Maglev Train
Rail: Shanghai Maglev Train Background
China experienced rapid economic growth in the 21st century
Greater demand for high speed passenger transportation resulted.
1999- Discussion of the feasibility of a Shanghai high speed rail began
Advantages like no contact, high speed, low energy consumption, and less environmental impact led to the approval of the project.
Train carries 574 and travels up to 505 km/hr
Rail: Shanghai Maglev Train Maglev: Electromagnetic
levitation
Electromagnetic field generated through the excitation of on board magnets and guideway magnets.
Magnets then attract each other, pulling the train upward.
Levitation gap stability controlled by current.
Rail: Shanghai Maglev Train Suspension:
Approx. 15mm (.59in)
Magnetic attraction varies inversely with the cube of the distance between the magnets.
Slight variations in distance will cause dramatic force changes.
How do we fix it? Closely monitoring and
constantly adjusting the current
Waterways
Waterways
Waterways include rivers, channels, ports, locks, etc…
12% of domestic and 80% of international goods are transported using waterways
Rivers like the Mississippi, Ohio, and Missouri are called “Working Rivers”
30,000 miles of navigable waterways
Controlling flows and dredging bottom sediment keep channels open at necessary water depth.
Waterways: Ports Allows for Intermodal transfer
of goods Standardized containers used e.g. barge to rail or truck
Approx 150 ports in the U.S. 3 of which rank in the top 20
worldwide busiest ports
China has more of the largest and busiest ports than any other country.
Waterways: Locks Permit ship travel
around a dam or through a shallow stretch
Gates open or close to control flow and consequently raise or lower a ship
Approx 250 locks in the US. (29 in the Mississippi alone)
Tunnels
Tunnels Very costly, but very effective.
Used primarily for rail and roadway transportation
Other uses Water supply conveyance Hydroelectric power Utilities Water storage
Tunnels: The Channel Tunnel AKA “Chunnel”
Runs between Britain and France
Declared one of the 7 Wonders of the Modern World by ASCE
30 miles long, 250 feet below sea level
Tunnels: Twin Tunnels Located in Shanghai, China,
under the Yangtze River. Holds 3 lanes of traffic and
one lane of rail Used the world’s largest
tunnel boring machine (50ft diameter)
ASCE Grades ASCE- American Society of Civil Engineers
The ASCE gives a report card for the infrastructure of the US
Most recent grades range from D- to C+ Roads: D- Mass Transit: D Waterways: D- Rail: C-
Why are these grades so low?