The construction of bridges is an essential part of expanding our network of roads and other infrastructure. Without the ability to cross water or gorges, for example, some locations would be unreachable by car. Construction of bridges requires a range of specialist skills that include surveying, masonry and carpentry. To begin with, surveyors have to take measurements of the river banks and standpoints on either side of the river where the bridge will be constructed. They also measure any gradient hills in the area that may affect the feasibility and cost of constructing a bridge. Then they use these measurements to calculate exactly how many tons each pylon on either bank can safely bear at that point. The structure itself includes three elements: abutments (the supports on either side), piers (the vertical supports in the middle) and arch or bridge itself). The first step is excavating a foundation pit for each pylon. These are typically 12 meters wide, 15 meters high and up to 20 meters long – although smaller versions can also be built for rivers that aren’t very wide or deep. A pile frame is then constructed around each support as a secondary support system to keep them from leaning outward under their own weight once they are filled with concrete. Next they are rammed with timber piles driven down vertically so they can handle being filled with concrete directly above them later on.
The pylons are built from tall, thick wooden or steel posts known as piles. They are driven straight down into the ground so that the tops of the piles are at the same level as the water level of the river. Careful measuring and mathematical calculations are needed here so that the tops of the piles are at the right level, but the base of the piles are strong enough to support the concrete once it’s poured. The piles are then filled with concrete to make them as sturdy as possible so they can support the vertical loads of the bridge as well as horizontal loads from the water flowing past them. This concrete is left to dry, and once it’s hard the piles can be removed from the base of the pylons.
The horizontal loads are supported by an arch formed using steel girders. The exact type of arch depends on the width of the river and the expected flow of water. Girders are usually made of steel and are tied together with steel bars and rivets. They are also connected to the pylons by a system of steel or reinforced concrete beams. Steel girders are supported by columns made of reinforced concrete. Girders are also tied together by a system of steel or reinforced concrete beams that run the entire length of the bridge. Girders made of steel are supported by columns made of reinforced concrete.
Piers are constructed from reinforced concrete. This concrete is poured into a wooden or steel form. The form is then removed, and the concrete is left to dry. The piers can be either solid or hollow. Piers are also connected to the pylons by a system of steel or reinforced concrete beams.
Bridge construction is an essential part of expanding our network of roads and other infrastructure. Without the ability to cross water or gorges, for example, some locations would be unreachable by car. The construction of bridges requires a range of specialist skills, including surveying, masonry and carpentry. To begin with, surveyors take measurements of the river banks and standpoints on either side of the river where the bridge will be constructed. They also measure any gradient hills in the area that may affect the feasibility and cost of constructing a bridge. Once they have these measurements, surveyors can calculate exactly how many tons each pylon on either bank can safely bear at that point. The structure itself includes three elements: abutments (the supports on either side), piers (the vertical supports in the middle) and arch or bridge itself). The first step is excavating a foundation pit for each pylon. These are typically 12 meters wide, 15 meters high and up to 20 meters long – although smaller versions can also be built for rivers that aren’t very wide or deep. A pile frame is then constructed around each support as a secondary support system to keep them from leaning outward under their own weight once they are filled with concrete. Next they are rammed with timber piles driven down vertically so they can handle being filled with concrete directly above them later on. Once the pylons and foundations have been constructed, the girders are lifted into place and connected together to form the skeleton of the bridge. The next step is to connect the girders to the piers and pylons. Finally, the bridge deck is constructed, and the bridge is ready to be used.
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