Underground has appeal to a wide range of readers because of the unique topic of exploration, which is not addressed in other sources. Technology, scientific theory, urban development, engineering principles, and social history are included in text and illustrations that make the complex understandable. In an orderly and interesting manner, Macaulay leads the reader on a fascinating exploration below city streets, where a vast, hidden system supports the life taking place above ground.
Bedrock, being the deepest level of soil, supports sand, clay, and rock, which must be considered before excavation takes place and a foundation is constructed. A foundation is important because it transfers the weight of the building to the material below. To prevent shifting and movement, the foundation must provide uniformity and stability; this becomes even more important if the ground below the building is unstable. Thoughts about multistory buildings or earthquakes remind the reader of the significance of this principle. The reader gains greater respect for the careful construction of the foundation. The description and diagrams of spread foot construction explain how soil and water are removed, laggings are braced, concrete is poured, and steel reinforcing rods are installed, all of which takes several weeks.
Being able to read and understand diagrams and following directions in a well-organized text will be skills enhanced by Macaulay’s book. Variations between the four major types of foundations for larger buildings...
(The entire section is 630 words.)