Coastal and Floodplain Construction Inspector's Practice Exam

Under what conditions is a single row of deep foundation elements without lateral bracing permitted?

1. A. For commercial buildings

2. B. For residential buildings only

3. C. For lightweight construction not exceeding two stories

4. D. For foundations exceeding 10 feet

The correct answer is: C. For lightweight construction not exceeding two stories

A single row of deep foundation elements without lateral bracing is permitted for lightweight construction not exceeding two stories because this type of construction typically exerts lower lateral forces compared to heavier structures. Lightweight materials reduce the overall weight and, consequently, the demands placed on the foundation system. This is crucial because deep foundation systems are primarily designed to support vertical loads, and for lightweight buildings, the need for lateral bracing becomes less critical. In general, lateral bracing is implemented to ensure stability and resist lateral movements caused by wind or seismic activity. However, for structures that do not exceed two stories and are constructed with lightweight materials, the risks associated with lateral movement are significantly reduced. Therefore, the design regulations allow for the omission of lateral bracing in these cases, simplifying construction and potentially reducing costs while still maintaining structural integrity. The other conditions, such as commercial and residential buildings or foundations exceeding 10 feet, may not align with the same considerations regarding weight and lateral forces, therefore necessitating additional bracing or more robust foundation designs.