145m in length The bridge is divided into two sections: the old structure (145m long) and a new curving, ramped connecting link (80m long), which is used to accommodate level fluctuations and create a point of entry on the south side. The new section was built by Ferguson Manufacturing Company at a cost of $3.5 million.
The world's longest cable-stayed bridge, it crosses the Columbia River between Portland, Oregon, and Vancouver, Washington. It connects the city of Portland with the city of Vancouver, including the towns of Lake Oswego and Milwaukie to its north and south, respectively. Opened in November 1996, the bridge carries six lanes of traffic and provides a direct route across the river for Interstate 5, the main highway between San Francisco and Seattle.
The bridge consists of a single central tower flanked by two shorter towers that support a curved roadway deck. The central tower is 465ft high and has two levels; the lower level contains the offices and public spaces, while the upper level offers scenic views. There are also three large ventilation fans located on the top floor of the central tower.
Each of the two shorter towers is also split into two levels. The bottom level of each tower houses the entrance gates and service areas while the top level provides parking for visitors or additional bridge maintenance facilities.
Lengthy journey Suspension bridges may reach between two and thirteen thousand feet in length. No other sort of bridge can stretch thus far. As a result, it is frequently the design used by builders to connect distant areas. Although they are often called "suspension bridges", this is not strictly true: most are actually cable-stayed bridges.
They are usually long enough to support a road or rail line across. Some are even long enough for a whole series of roads or rails to cross at one location!
The longest suspension bridge in the world is also located in Canada. It connects Quebec with New Brunswick and has a total length of just over four miles (six kilometers).
There are several different types of bridge that go beyond the typical suspension bridge. One type of bridge used widely in Europe is the truss bridge. This consists of three main sections of steel connected by wooden members. The bridge deck is made of concrete or asphalt.
Another type of bridge is the through truss. This has two sets of triangles connected by webbing. On top of the triangles are horizontal members called chords. The ends of the chords are attached to towers or piers.
A third type of bridge is the box truss.
The main span is 225' long, with a vertical clearance of 65' and a horizontal clearance of 180' across the Intracoastal Waterway. The average span is 136 feet. The bridge was built in 25 months and opened to traffic five months ahead of schedule. It was the first major project undertaken by the newly formed Maryland State Highway Administration.
The tower stands 556 feet high and the deck is 80 feet wide. The main span rests on four massive foundations, each one weighing more than 20,000 pounds. The main cables are made of steel with a diameter of only 6 inches, and they are held up by hundreds of small towers that stretch all over the bridge like tiny sticks on a giant lawnmower blade. The total weight of the bridge itself is about 740,000 pounds.
There have been calls from some citizens for the removal of the Mid-Bay Bridge toll booths, but so far there has been no indication that this will happen. The state government has said that it would cost $10 million to $15 million to remove the toll booths; this money is not available right now because the state is still recovering from budget cuts made several years ago.
In the meantime, drivers can use the Bay Bridge or Ocean View Bridge to get across the bay, but they cannot use both bridges in the same direction at the same time.