A bridge foundation, also known as a bridge pier, is used to support the bridge span and transmit the weight to the earth. Simply put, the bridge foundation must be strong enough to support not just the vertical load of the substructure but also the lateral stress of the bridge span.
The foundation must also be able to resist corrosion from the elements, such as wind, rain, and snow. Finally, it must provide a stable base for pouring the concrete decking or other surface material.
These requirements are met by using materials that give the required strength and durability and by applying appropriate techniques during construction.
The purpose of the foundation is to distribute the weight of the bridge across a large area so that much of this weight is not concentrated in one place. This prevents damage to the land under the bridge if there is any kind of instability in the soil. It also helps to prevent damage to buildings and roads near the bridge site.
There are two types of foundations: deep and shallow. Deep foundations consist of pillars or stumps embedded in the ground that support the bridge deck. The height of these pillars or stumps is called the depth of the foundation. Shallow foundations are simply the sides of the bridge bed itself. They can be made of dirt or concrete, but they must be at least as tall as the maximum expected load on the structure.
A bridge's foundation (or base) is the part that links the structure to the soil and transmits loads from the structure to the ground below. It will be supported by two supports, one at each end. These components immediately sustain the bridge's downward weight as well as any vehicles passing beneath it. They are also called anchor blocks because they serve to secure the bridge against sliding down the hillside.
The support on a bridge is its means of connecting itself to another object (such as a wall) so that it can bear some of the weight above it. The type of support used depends on several factors such as price, availability, and function. For example, a bridge may use eyebars when building it for use with horses or carts, while a bridge built for heavy trucks may use girders instead.
When a bridge fails, it usually does so due to damage caused by excessive loadings over time or lack of maintenance. A common cause of failure for many types of bridges is being overloaded beyond their capacity to span safely. For example, if a car drives onto an otherwise-sound bridge deck but there is no barrier between the vehicle and the river far below, then the weight of the vehicle will pull down the side of the bridge toward the lane in which it is traveling, causing further damage to the bridge until it collapses.
Other causes of failure include collisions, earthquakes, fires, and vandalism.
The term "base" can also refer to the entire bridge structure, including its abutments and approaches.
The word "base" is used in different ways in engineering terminology. In general, it refers to the supporting structure for a building or bridge, such as the base of a wall or stairway. In construction, the word "base" is often used instead of "foundations", which includes not only the physical foundations but also the underlying structural elements of a building such as its footings and basement floor. Finally, the word "base" is used in bridge engineering to describe the portion of the bridge that connects the piers or other support structures to the ground or some other kind of bearing surface.
Bridges require support on both sides if they are not to collapse under their own weight. Therefore, bridges are usually built with abutments at either end; these are large rocks or other stable objects situated near the top of a bank or beside a road where they can bear any load that might be applied to them. The space between the ends of the abutments is called the key seat.