California Supplemental (CSE) Practice Exam

What does Exposure D indicate in terms of ground surface irregularities?

1. Urban and densely constructed areas

2. Open terrain with scattered obstructions

3. Flat, unobstructed areas

4. Heavily wooded areas

The correct answer is: Flat, unobstructed areas

Exposure D refers to flat, unobstructed areas that are free from significant obstructions, such as trees or buildings. In wind engineering and assessing environmental impacts, these areas are characterized by having few features that can disrupt airflow. This makes Exposure D important when considering wind loading on structures, as wind can impact buildings differently depending on the surface irregularity surrounding them. In contrast, the other options present different types of exposures where the existence of various features significantly affects the wind patterns. Urban and densely constructed areas would present a very different exposure scenario, often involving numerous high-rises and buildings that disrupt wind flow. Open terrain with scattered obstructions indicates that there are some features present, which would alter the wind's characteristics. Heavily wooded areas would also block and redirect airflow, creating even more complex wind patterns. Understanding these differences helps in the design and resilience of structures based on their location and exposure classification.