CH 6 Flashcards
(19 cards)
test pits or test borings are used to measure:
(3)
pg 170
soils qualities
water table
frost line
test pits
pg 170
may be up to 8 feet deep
used to observe and measure strata (soil layers)
test borings
pg 170
used when test pit may not reach deep enough
small bore tube and driving hammer
multiple test borings needed to provide overview of conditions
factors that influence the type and depth of the foundation:
(8)
pg 170
size of the structure
soil conditions at the site
type of building
buildings intended structure and contents
lateral forces (seismic and wind)
working space requirements
influence on adjacent exposures
building codes and regulations
shallow foundations:
pg 171
transfers the weight of the building directly to the soil at the base of the building
usually use reinforced concrete footings to transmit the buildings load to the soil in a limited amount of space
Wall footing:
pg 171
type of shallow foundation that includes a wide thick area to distribute the weight of a wall on the bearing soil (aka strip footing)
continuous strip of concrete that runs the full length of the wall. wider and deeper at the base
ways concrete footings are constructed:
(3)
pg 171
increased thickness of a floor slab at the edges (monolithic floor)
thick and wide strip of concrete under full story high walls that create a full or partial basement
thick and wide strip of concrete under a wall that supports a raised floor with a crawl space
column footings
pg 171
square pad of concrete that supports a column, often reinforced, limited to relatively small load
grillage footings
pg 171
parallel structural beams (often steel) arranged in multiple layers at right angles to each other. encased in concrete
similar to column footing but designed to transmit loads over wider area
mat slab foundation
pg 172
thick slab under entire area of building
may be several feet thick and heavily enforced
floating foundation
pg 172
weight of soil removed is equal to the weight of the building
total weight supported by each soil layer remains the same before and after excavation
weight of soil
pg 172
one story of soil can equal 5-8 stories of a building
Deep foundations
pg 172
piles or piers that penetrate layers of soil to reach soil or rock that can support the weight of the building
Piles:
pg 173
driven into the ground and support a load by transferring the load either through friction with surrounding soil or through contact with rock or other stable soil
piers
pg 173
post-and-pier
system of upright posts mounted to wedge shaped concrete piers
construction begins with drilling or digging a shaft then filling it with concrete
pier with a footing is a belled pier
materials most commonly used for foundation walls
pg 174
concrete and masonry(brick or concrete block) secured with mortar
EPS
pg 174
Expanded polystyrene
hollow eps blocks filled with concrete: insulated concrete form (ICF) construction
Types of foundation settlement motion
(3)
pg 175
settlement-downward motion
heaving- upward motion
lateral displacement-outward movement
shoring vs underpinning
pg 176
shoring is temporary support
underpinning is permanent
