A strap footing is a type of foundation used in construction when two columns have independent footings that need to be connected by a beam. This approach is employed when the distance between the columns is significant enough that creating a combined trapezoidal footing would result in a narrow and potentially unstable foundation, with high bending moments that could compromise the structural integrity of the building.
To avoid these issues, engineers opt to use two independent footings for each column, connected by a beam, to create a more stable foundation. The use of a strap footing allows for the necessary distance between the columns to be maintained while still ensuring that the structure remains secure and sturdy. This approach is especially useful when dealing with larger buildings, where the distance between columns can be significant.
Overall, a strap footing is a practical and effective solution to the challenge of connecting two independent footings of columns that are too far apart for a traditional combined trapezoidal footing. By using a beam to connect the two footings, engineers can create a stable foundation that ensures the structural integrity of the building is maintained over time.
A strap beam is a type of structural element that is commonly used in building foundations. Unlike other foundation types, the strap beam does not remain in contact with the soil. This means that it does not transfer any pressure to the soil.
The strap beam is assumed to be infinitely stiff, meaning that it can support a large amount of weight without bending or breaking. This stiffness allows it to serve a specific purpose: transferring column loads to the soil with equal and uniform soil pressure under both footings.
In essence, the strap beam acts as a bridge between the two footings, ensuring that the weight of the columns is distributed evenly and does not cause any uneven settling of the foundation. By distributing the load in this way, the strap beam helps to ensure the stability and longevity of the building.