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?