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FOUNDATIONS
(WORKING DRAWING)
Footings & Foundations
INTRODUCTION TO FOUNDATIONS
Function of a foundation is to transfer
the structural loads from a building
safely into the ground.
A larger and heavier building of
masonry, steel, or concrete would
require its foundations to go deeper
into earth such that the soil or the rock
on which it is founded is competent to
carry its massive loads.
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Foundation Components
Footing
Footings & Foundations
Foundation Components
(to attach wood stud sill plate)
(moves water away
from building)
(to keep water off of foundation wall)
(separates slab from foundation wall)
(to keep water off of slab)
(moves water away from building)
(to keep water off of slab & moisture barrier)
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Site Preparation
•Remove trees and any debris
•Remove top soil (4-6” below surface)
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Site Layout
•Ensure lot lines are known & setbacks are complete
•Layout building perimeter
•Use batter boards
•Establish building corners & building perimeter
•Use surveying instruments
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Excavation
•Excavate foundation along line created by batter boards
•Excavate remainder of soil inside perimeter
•Don’t excavate inside soil if slab on grade
•If deep foundation, taper edges to prevent collapse
•If soil unstable, or very deep - use shoring
Footings & Foundations
Pour Footings
•Construct formwork (if required)
•Install reinforcement (rebar) for footings
•(protrudes above footing to tie-into
foundation wall)
•Pour concrete footings
•Smooth / finish surface
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Rules of Thumb
•Footing shall be below frost line
•Footing width usually 2x height
•Typical size (24” wide x 12” tall)
•Rebar is usually 3” from edge of concrete
•Crawl spaces should have rigid insulation
along the interior face of the foundation wall
Footings & Foundations
TYPES OF FOUNDATION
Major Building Parts
Superstructure
Substructure
Foundation
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TYPES OF FOUNDATION
Two types foundations : Shallow and
Deep –
Depends on whether the load transfer is at
deeper depths or shallower depths
- Need for these two types (soil strength,
ground water conditions, foundation loads,
construction methods and impact on
adjacent property)
Footings & Foundations
TYPES OF FOUNDATION
Shallow foundations (column footings
without or with tie/grade beams, individual
or combined wall footing, slab on grade,
raft)
- Deep foundations (caissons with or
without sockets, end bearing or friction
piles, pile groups), made of concrete
(regular or site-cast) or steel or wood
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Shallow Foundations

Requirements
– Suitable soil bearing capacity
– Undisturbed soil or engineered fill

Basic types or configurations
– Column footings
– Wall or strip footings
Footings & Foundations
Combination Spread & Strip Footing
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Shallow Foundations
Stepped strip
footings
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Grade Beams
Footings & Foundations
Shallow Foundations
 Mat
foundation
 Floating
(Mat)
foundation
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Deep Foundations - Purpose
Transfer building loads deep into the earth
Basic types
– Drilled (& poured)
– Driven
Footings & Foundations
Pile material
Steel; H- piles, Steel pipe
 Concrete; Site cast or Precast
 Wood; Timber
 Composite

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Driven Piles
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Precast Concrete Plies
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