Foundation Systems:
    geometric analogies
           point
           line
           plane

     Superstructure
           Substructure
           Footing
           Undisturbed Soil

Foundation Problems:
         cracking
         settling
         sliding
         overturning

Footing Types:
     piles
             wood
             steel
             concrete
     spread footings
             concrete

Footing Size
Foundation Walls:
   foundation = 2 x wall thickness

       w = 2 x t
       w = t + 1/2T + 1/2T

if footing is wider
it becomes subject to bending
increase amount of rebar
rebar to be covered by 
min. 3” concrete 

Footing Size
Column & Piers:
   A = P / SA = horizontal bearing surface
                of footing
P = Column Load in Pounds
S = Soil Bearing Capacity
                lbs/ s.f.

Foundation Types:
                Pier Foundations
                        individual
                        column footings
                        combined with
                        strip footing
                        wood
                        concrete
                        masonry
                Pile Foundations
                        in clusters
                        end-bearing pile
                        friction pile
                        wood
                        steel
                        concrete
                Caissons
                        concrete sitecast
                        into drilled holes
                        bell caison
                        socketed caison

                Wall Foundations
                        waterproofing
                        stepped footings

                Slab Foundations
                        slab on grade
                        thickened slab
                                        carry wall & column
                        mat foundation
                                        joint column footings

Pier Foundations:

Wood:
        limit candilever to 1/4
                back span
        beam span
        joist span

Footings:
        concrete pad
                8” depth min.
                1’-6” min. width
                4’-0” min. backfill
        concrete collar
                1’-6” min. width
                2’-0” above frost line
                                top of grade
                12” below frost line
                                lag bolts
        concrete backfill
                entire length of pole

pier foundations - concrete
        max. unsupported height
                = 10 x min. width

Wood Coloumn
        6” above ground min.

Concrete Block
        Basement Wall
        8” min.

Poured Concrete
        Basement Wall
        8” min.

Concrete Expansion Joint
        1/2” min.
        
Drain tile
        4” diameter

Backfill
        gravel

Slab - finished grade 
        6” min.
        exposed concrete
        parged with cement plaster

Grade to slope
        1/2” per foot min.

FOOTINGS
see P&A 484 - 4495

The design of a Column footing is usually

based on the following considerations:
1. maximum soil pressure
2. control of settlement
3. size of column
4. shear stress limit for the concrete
5. flexural stress and development length limits
6. footing thickness for development of column reinforcing

Load Tables for Column Footings
(P&A  492-494)