When considering soil under a footing, what should be noted about smaller layers with allowable bearing value?

When assessing soil under a footing for construction, particularly in terms of allowable bearing values, it's important to recognize that smaller layers may have different properties compared to larger deposits. The correct approach is to use the smaller value for load determinations because this provides a conservative estimate that accounts for variations in soil strength.

Using the smaller allowable bearing value ensures that the calculations remain within safe limits, reducing the risk of overstressing the soil, which could lead to settling, shear failure, or other structural issues. This is a critical consideration in structural engineering and geotechnical assessments, where safety is paramount.

In practice, this approach acknowledges that smaller soil layers could be weaker and might not support as much load as the larger layers. By adopting the smaller value, engineers can design footings that are safe and robust, ensuring the structure's integrity over its lifespan. This cautious methodology also adheres to best practices in construction, prioritizing safety and reliability.