Movable Bridges Around The World
Movable bridges are the special type of bridges which can move to allow the vessels and boats in the waterway. These types of bridges are only open for waterways because these bridges stop the road traffic while moving so these movable bridges can not be used on the road.
There are many movable bridges in the USA. These bridges were built in the early 20th century.
Types of Movable Bridges
1. Bascule Bridge
2. Swing Bridge
3. Vertical Lifting Bridge
4. Special types of Movable Bridge
This type of bridge is fixed and the axis of this bridge is perpendicular to the longitudinal axis of the bridge. This bridge is also known as drawbridge. The bridge is hinged on the horizontal axis and it is situated at the center of gravity. In result a balance is created between the weights of the bridge on either side.
Single Leaf Bascule Bridge
Leaf is the part of the bridge which pivots at horizontal axis and is open for the water traffic.
Double Leaf Bascule Bridge
This type of bridge is structurally very strong, reliable, and the construction and operations are very affordable.
Vertical Lifting Bridge
This type of bridge is mostly used in the riverway. It is a combination of the span of a truss. Towers support this bridge at the end of span. It is a very balanced bridge overall. The span moves in the vertical direction to pass the water traffic.
The machinery system which moves up and down the span, this is fixed on the span itself. So it is called a span drive vertical lift bridge. If the responsible machine is fixed on the towers then it is known as tower drive vertical lift bridge. This type of bridge is way more stable than others and it is used where long spans are required.
This type of bridge is placed on the horizontal axis and it is also able to turn the vertical axis to provide an open road for water traffic. On the pivotal pier a bearing is installed and the horizontal plane rests on this pivotal pier. After the closing of the water traffic, the ends of the span of this bridge rests on the abutments.
When there is a need to open the water traffic, the end span must be free and it will be supported by the pivotal pier. The swing bridge must be supported horizontally and vertically so that it can carry the traffic and prevent the stressing. The span of Swing Bridge can either be truss or plate girder. But the use of plate girder is more affordable.
Special Types of Movable Bridges
These bridges are considered special because the bridges are rarely constructed. Special types of bridges are:
Removable Spans Bridge
1. Increase in the application of loads
2. Usage of newly developed materials
3. Safety precautions and concern