You must have seen big bridges built over rivers and seas in the country. But has this question ever come to your mind that how are these bridges and their pillars made to stop water? Today we will give you the answer to this question.
How are bridges built?
The work of bridges built on rivers and seas. Happens at another place. From where these goods come. After which they are set on the pillars. In the language of civil engineering, these are called pre-cast concrete labs. A bridge is made by attaching these pre-cast plates to the pillars. The work of making pillars is done at the same site. In this, first of all the work of laying the foundation is done. The foundation plan is also made in advance depending on the size of the entire project.
Foundation of the bridge inside the rivers
While building bridges over rivers and seas, the foundation laid in the middle of water is called cofferdam. This is a huge drum made of metal. The cofferdam is placed underwater in place of the pillars with the help of a crane. Earlier, the flow of water was diverted or stopped by building earthen dams. But in such a situation there was a danger of the dam breaking. But now cofferdams are made from large sheets of steel. Their shape can be round or square as per requirement. Their size is decided on the basis of length, width, water depth and water flow of the bridge.
How do steel cofferdams work
Due to the cofferdam, water flows away from its surroundings. When the cofferdam gets filled with water, it is taken out through pipes. When soil becomes visible beneath it, engineers go inside it and start work. Then engineers prepare strong pillars using cement, concrete and bars. After this, the pre-cast slabs of the bridge prepared at another site are brought and set on the pillars.
How pillars are made in deep water >
If the water is too deep, cofferdams are of no use. For this, some points are decided by going to the bottom in deep water and doing research. After this, the soil at those points is checked whether it is solid enough to make pillars or not. When the soil is found suitable as per requirement, deep pits are made at the fixed points. After this, pipes are inserted in the pits. These are brought up to the sea level or river bed. After this, pillars are made by draining out the water and inserting a network of cement concrete and steel bars in the pipes. After the pillars are made, the pre-cast slabs are brought and fixed.
