178 Section 4 Reading Prints
support stratum or driven to friction resistance of
the soil (this type of pile is referred to as a friction
pile). A friction pile works on the principle of
frictional resistance on the sides of the pile from
the soil into which it has been driven. When you
look at this type of foundation system on a draw-
ing, you will usually see several steel piles clus-
tered together and topped with a pile cap to make
the cluster work as a total load-carrying system.
See Figure 10-10.
Foundation Elevations
A critical part of starting a building properly
is constructing the foundation at the designed
elevation. An elevation is a measurement refer-
enced to a known point. Elevations for a foun-
dation are marked on the foundation plan view.
SECTION VIEW
Concrete or
steel column
Pile cap
(not always
required with
caissons)
Caisson
(typically
18" to 72"
in diameter)
Suitable soil
support
material
or rock
Rock Soil
Figure 10-9.
Drilled concrete caisson.
SECTION VIEW
PLAN VIEW
Steel
H-piling
Concrete
pile cap
Column
Building
load
Concrete
pile cap
Steel
H-piling
Soil resistance
is the primary
support
Figure 10-10.
Building foundation system using steel
H-piling.
Depending on the type of foundation, the eleva-
tions will be given for various parts of the system.
For wall footings, the top of the footing is given