Bridges are one of the most important constructions of the modern civilization. It connects distant places with each other and people can easily travel from one place to another. We all have travelled by many bridges some time or the other. But, have we ever thought how the bridges are built over water?
Not only just the river banks are connected with bridges, but even two creeks or more creeks of the oceans are also connected with magnificent bridges. Building flyovers on the concrete roads is easier than building bridges over water. Here is something interesting and knowledgeable that will stun you about the advancement of modern civilization, power of construction and technology.
Factors associated with building bridges:
Before you go into how bridges are made, there are a few things that you need to keep in mind. The bridges over water can be of two types – the floating ones and the permanent ones. Quite obviously, the floating ones are not permanent and are used only temporarily. Hence, they do not need a foundation. But the permanent bridges need a foundation and for that there are three basic factors that need to be kept in mind. These are –
- The condition of the site
- The technical ability and engineering capacity of the contractor
- The technology available in the country.
The first two factors are dependent on the engineers to measure. But, the factor of availability of technological support depends entirely on the construction equipment that is available. For that matter it must be mentioned that there are various types of construction equipment available in the market that are specially designed to support bridge construction.
Steps of constructing a bridge:
When bridges are built over large water bodies such as a very deep river or even the sea, the following steps are followed.
- Constructing the Foundation:
In order to build the foundation, a bed is sunk inside the waterbed from the top. It is like a frame to the pillars that will hold the bridge in place. After that, a support pier is made with the help of rigs.
- Construction of Cofferdam:
Around the support pier and rigs, a Cofferdam is made. It is a special type of wall that is created surrounding the foundation. Continuous pumping removes the water from inside. The area is completely dried out and then, the foundation is made.
- Bringing everything together:
After the construction of the foundation, the support piers are either cast in the yard or cast in place. Sometimes, this process is done elsewhere and then, barges are used to bring everything together.
Once this is done, the gaps are joined with segments of concrete structure.
Sometimes, the segments are supported by huge suspension cables. As they are brought into position, they are stitched together. Though these are the most common methods of constructing a bridge, there are other methods as well that are followed to construct the bridges. Certainly, the methods that are followed for bridges in shallow water are different from that in the deep water.