Construction Supervisor License Practice Exam

What is the maximum depth of unbalanced fill permitted for an 8" thick plain concrete foundation wall that is eight feet high?

1. 5 feet

2. 6 feet

3. 7 feet

4. 8 feet

The correct answer is: 5 feet

For a plain concrete foundation wall that is eight feet in height, the consideration of unbalanced fill is critical for ensuring the structural integrity and stability of the wall. In construction, unbalanced fill refers to the material added on one side of the wall that exerts lateral pressure due to its weight. The maximum depth of unbalanced fill is typically dictated by both structural engineering principles and code requirements, aimed at preventing excessive lateral loads that could lead to cracking or failure of the wall. Generally, this depth is determined to be one-half of the wall height, which in this case would be four feet. However, given that the wall itself is already eight feet tall, it's important to ensure that the load from the unbalanced fill does not exceed what the foundation can handle. The choice that indicates a maximum unbalanced fill depth of five feet is aligned with standard practices, as it provides a conservative limit for stability while factoring in the sheer height of the wall and the potential for pressure differentials. In situations where unbalanced fill exceeds the recommended limits, there is an increased risk of wall failure, which underlines the importance of adhering to prescribed maximum depths. This ensures that the foundation wall can accommodate the lateral loads without compromising structural integrity.