Caisson Foundation

Definition

A caisson foundation is a deep foundation type that is typically used in the construction of bridges and other heavy structures, designed to transmit the load from the structure to the soil or rock beneath. These foundations are usually constructed as large, watertight structures that are sunk into the ground and filled with concrete, providing stability and support. The use of caisson foundations is particularly valuable in areas with poor soil conditions or when working in water, where traditional foundations may not be feasible.

5 Must Know Facts For Your Next Test

1. Caisson foundations can be classified into two main types: open caissons and pneumatic caissons, depending on how they are constructed and installed.
2. Open caissons are used when excavation can be done safely and effectively, while pneumatic caissons involve pressurized air to keep water out during construction.
3. The size and shape of a caisson foundation are determined based on the load it must support and the soil conditions at the site.
4. Caissons can be constructed using various materials, including reinforced concrete and steel, which adds to their strength and durability.
5. One major advantage of caisson foundations is their ability to provide stability in challenging environments, such as underwater construction or areas with unstable soil.

Review Questions

• How do caisson foundations differ from pile foundations in terms of construction methods and applications?
  • Caisson foundations differ from pile foundations mainly in their construction methods and applications. Caissons are large, watertight structures that are excavated or sunk into the ground and filled with concrete, while piles are slender columns driven into the soil. Caissons are often used in locations with poor soil conditions or underwater construction due to their stability, whereas pile foundations may be preferred in tighter spaces or when rapid installation is required.
• Discuss the advantages of using caisson foundations over traditional shallow foundations in bridge engineering.
  • The advantages of using caisson foundations over traditional shallow foundations in bridge engineering include improved load distribution, enhanced stability in poor soil conditions, and greater resistance to lateral forces. Caissons can reach deeper soil layers with higher bearing capacity, making them ideal for heavy structures like bridges. Additionally, their construction methods allow for effective use in challenging environments such as riverbeds or coastal areas, where shallow foundations might fail.
• Evaluate the impact of soil bearing capacity on the design and implementation of caisson foundations in bridge projects.
  • Soil bearing capacity plays a crucial role in the design and implementation of caisson foundations for bridge projects. Engineers must assess the bearing capacity of the underlying soil to determine the appropriate size and depth of the caissons needed to support the structure's loads effectively. If the soil has low bearing capacity, larger or more numerous caissons may be required, leading to increased construction costs. Moreover, an accurate evaluation of soil conditions helps ensure safety and longevity for bridges built on these foundational systems.

Related terms

Pile Foundation: A type of deep foundation that consists of long, slender columns driven into the ground to transfer loads to deeper, more stable soil layers.

Footing: A structural element that supports a building or bridge, typically located at the base and designed to distribute the load over a larger area.

Soil Bearing Capacity: The ability of soil to support the loads applied to the ground, which is a critical factor in foundation design.