Foundations

FOUNDATION
INTRODUCTION:
                                      The subject of foundation engineering deals with design of various types of sub structures under different soil and environmental conditions During the design the designer has to make use of properties of soil , the theories pertaining to the design and his practical experience to adjust the design to suit the field condition
TYPES OF FOUNDATION:
Residential foundation systems can be divided into six general categories:
• No foundation
• Partial foundation
• Post and pier throughout
• Perimeter footing with interior posts
• Continuous perimeter and interior footings
• Continuous footings with a slab floor on grade.
With no foundation, or too small a partial foundation, the horizontal forces in the building cannot be transferred safely into the ground (Fig. 5.1). There is a similar discontinuity in the load path with a post and pier foundation (Fig. 5.2). You will learn more about post and pier systems in the next section, Retrofitting Post and Pier Type Houses.
When a building has a continuous perimeter footing, the horizontal force can transfer from the shear wall to footing and then into the ground. Interior supports are usually posts and girders or continuous cripple walls (Fig. 5.3 & 5.4). Unless there are shear walls above, these systems provide vertical support only and are not part of the horizontal force-resisting system. They are simply part of the gravity force-resisting system.
FOUNDATION MATERIAL

            The foundation would normally consist of one or more the following
materials :
· concrete
· concrete block
· brick
· stone.
If the concrete block is fully grouted and reinforced, it will tend to act as concrete. If it is not grouted or reinforced, it will act as brick or stone Continuous concrete footings and foundation walls are the best material type. This is one reason their presence is required in some prescriptive standards. Expansion anchors require...