Six Main Types of Bridges

When building a bridge, engineers must consider a number of factors. Different bridge styles distribute stresses different ways. Engineers must take the length and width of the bridge, local environmental conditions and building materials into account to decide what type of bridge to build. To know what kind of bridge is realistic for what environment, then knowing about the 6 different types of bridges is important. Using the wrong type can result in disasters affecting travel and safety.

Arch as Simple Bridge

Arch bridges use arches as the main structural component. Basic arch bridges are differentiated from one another by the number of hinges used to allow the bridge to accommodate different loads and stresses. Some arch bridges don't include any hinges at all. Arch bridges include those where the arch is underneath the bridge and not above it, provided the trusses are arranged vertically and not diagonally. The Hell Gate Bridge in New York is an example of an arch bridge.

Basic Beam Bridge Construction

Beam bridges are very basic bridge constructions that have pieces supported on either end of the bridge. Modern bridges frequently use leg supports to distribute the load. Two main types of leg supports are used: the inclined leg which involves a single inclined leg at each support point and a v-leg, which uses a two-piece leg shaped like the letter "V." A haunched girder bridge is a type of beam bridge that uses flanged pieces at the extremities of the bridge. Beam bridges work much like a log overlapping the two sides of a ravine. An example of a beam bridge is the Lake Pontchartrain Causeway in southern Louisiana.

Cable-Stayed Bridge Structures

Cable-stayed bridges are one of two bridge types preferred for longer bridges. Columns are erected as support with cables to support the deck of the bridge. The design is similar to a suspension bridge but instead of the deck being curved, it is flat. In New York City, the East 153rd Street Bridge is a cable-stayed bridge.

Cantilevered Bridge Types

Kinds of bridges also include cantilevered bridges which are built around horizontal structures supported on only one end. Some cantilevered bridges are very similar in appearance to arch bridges; however, they are supported by diagonal bracing rather than vertical bracing. These types of cantilevered bridges are known as spandrel braced. The other type of cantilevered bridge is the cantilever through truss formation, where trusses are either above the bridge or both above and below. An example of a cantilevered bridge is the Queensboro Bridge.

Suspension Design Bridges

The suspension design is another one of the 6 kinds of bridges for long spans with pylons or towers as the main supports. Ropes or cables reach from the supports to hold the bridge and traffic weight. With only the supports in the ground, suspension bridges respond to wind and traffic. Some of the most famous examples of suspension bridges are Golden Gate Bridge in San Francisco, Akashi Kaikyō Bridge in Japan and Brooklyn Bridge in New York City.

The Simple Bridge With Trusses

The truss bridge is a simple bridge design that includes most covered bridges. Two main kinds of bridge types of uncovered truss bridges are used: the king post which has two diagonal posts supported by a single vertical post in the center and the queen post which has two diagonal posts, two vertical posts and a horizontal piece which connects the two vertical posts at the top. New York's Kosciuszco Bridge is a truss bridge example.