180 likes | 199 Views
Chapter. 18. Footings, Foundations, and Concrete. Excavation. Excavation for footings should extend a minimum of 6” below the average maximum frost penetration depth. Local building codes usually specify the minimum footing depth for a given area. Excavation. Frost Penetration Chart.
E N D
Chapter 18 Footings, Foundations, and Concrete
Excavation • Excavation for footings should extend a minimum of 6” below the average maximum frost penetration depth. • Local building codes usually specify the minimum footing depth for a given area.
Excavation Frost Penetration Chart • Average depth of frost penetration in inches.
Footings The footing distributes the weight of the building, which is transmitted through the foundation wall, over a broad area.
Footings Footings are generally poured concrete. Footingsincrease the supporting capacity of foundation walls by dispersing the load over a larger area. Soil bearing capacity and weight of the structure determine the size and type of footing. Poor soil may require wider footings.
Footings Footing size is typically based on the foundation wall thickness. The thickness generally equals the foundation wall thickness and the width is twice the wall thickness.
Chimney Footings • Chimney footings are more massive than regular footings • Chimney footings should be 12 inches thick and extend 6 inches beyond perimeter of chimney.
Foundation Walls • Foundation walls extend from first floor to footing. • Variety of materials may be used for foundation walls such as Cast concrete, concrete block, brick, stone and pressure-treated wood.
T-Foundations • The most common type of foundation is the foundation wall and footing. This combination is commonly known as the T-foundation.
T-Foundation Application 8” Basement wall and Footing
Post (Column) Foundation • Posts (columns) are used in basements where span is too long and are used to support a beam. • The column has a footing
Pilasters • A pilaster is a rectangular column that projects from a wall • Pilasters are used to strengthen basement walls • The distance between pilasters should not exceed 15' in an 8" wall and 18' in a 10" wall • Pilasters are also used to support beams
Firecuts • A firecut is used when floor joists are placed directly into solid masonry walls. • Each joist end is cut at an angle to prevent wall damage in case of fire.