Lead-in. Look at the picture and answer the following questions

Look at the picture and answer the following questions

1. Why is the bridge-tunnel considered unique?

2. What do you think about the length of the complex?

3. What is the main purpose of the bridge-tunnel complex?

Brief information:

Location: Cape Charles and Virginia Beach, Virginia, USA

Completion Date: 1964

Cost: $200 million

Length: 89,760 feet (total length); 79,200 feet (bridge length)

Type: Beam, tunnel

Purpose: Roadway

Materials: Steel, concrete

Longest Single Span: 100 feet

Engineer(s): Sverdrup & Parcel

Distinguished as an "Outstanding Civil Engineering Achievement" by the American Society of Civil Engineers in 1965, the Chesapeake Bay Bridge-Tunnel is nothing short of a modern engineering wonder. Dipping over and under open waters with a complex chain of artificial islands, tunnels, and bridges, the Chesapeake Bay Bridge provides a direct link between Southeastern Virginia and the Delmarva Peninsula.

The bridge-tunnel complex is 17.6 miles long from shore to shore, and it cuts 95 miles off the journey between Virginia Beach and points north of Wilmington, Delaware. The majority of the bridge-tunnel complex is above the water, supported by more than 5,000 piers. But due to the importance of shipping in the bay, the crossing was sunk deep beneath the bay in two mile-long tunnels to allow the passage of ships. Four artificial islands, each with approximately 10 acres of surface, provide the portals by which the road enters the tunnels. The original Chesapeake Bay Bridge-Tunnel 2-lane crossing consists of 12.5 miles of low level concrete bridge trestles, two tunnels each about one mile long, two high-level steel bridges, four man-made portal islands each 1,500 feet long, 1.5 miles of earthfill causeway across Fisherman Island, and about 5.5 miles of land approach highway. The roadway on the bridge portions is 28 feet wide.

The individual components of the Bridge-Tunnel are not the longest or the largest ever built; however, the total project is unique in the number of different types of major structures included in one crossing and the fact that construction was accomplished under the severe conditions imposed by northeasters, hurricanes, and the unpredictable Atlantic Ocean. It's quite an eerie experience to be driving along and see the road you're on disappear into the bay. Since it opened (1965), more than 67 million vehicles have crossed the Chesapeake Bay Bridge-Tunnel. It's possible that many just crossed it for the thrill of it! It is mandatory that the bridge be checked and serviced every five years. Since servicing the bridge takes about five years, the work never stops.

Fast Facts:

· Following its opening in 1964, the Bridge-Tunnel was selected as "One of the Seven Engineering Wonders of the Modern World" in a worldwide competition that included more than 100 major projects.

· Since it opened in 1965, more than 67 million vehicles have crossed the Chesapeake Bay Bridge-Tunnel.

· One artificial island actually has a gift shop, restrooms, and a parking lot to allow drivers to stretch, relax, and enjoy the scenic view.

· Four artificial islands, each with approximately 10 acres of surface, provide the portals by which the road enters the tunnels.

Дата добавления: 2015-08-27