TABLE OF CONTENTS Robert W. Day, P.E.
A foundation is defined as that part of the structure that supports the weight and loads acting on the structure and transmits this load to underlying soil or rock. Foundations are commonly divided into two categories: shallow and deep foundations. Table 16.1 presents a list of common types of foundations. The most frequently encountered conditions that cause damage to foundations and structures are settlement, expansive soil, lateral movement, and deterioration. Table 16.21 presents a list of the typical types of problems that affect foundations.
| Category | Common types | Comments |
|---|---|---|
| Shallow foundations | Spread footings (also called pad footings) | Spread footings are often square in plan view, are of uniform reinforced-concrete thickness, and are used to support a single-column load located directly in the center of the footing. |
| Strip footings (also called wall footings) | Strip or wall footings are often used for load-bearing walls. They are usually long, reinforced-concrete members of uniform width and shallow depth. | |
| Combined footings | Reinforced-concrete combined footings are often rectangular or trapezoidal in plan view, and carry more than one column load. | |
| Conventional slab-on-grade | A continuous reinforced-concrete foundation consisting of bearing wall footings and a slab-on-grade. Concrete reinforcement often consists of steel rebar in the footings and wire mesh in the concrete slab. | |
| Post-tensioned slab-on-grade | A continuous post-tensioned concrete foundation. The post-tensioning effect is created by tensioning steel tendons or cables embedded within the concrete. Common post-tensioned foundations are the ribbed foundation, California slab, and PTI... |
