Chapter 6 - Foundations Flashcards
Surface materials:
The allowable foundation pressure for sandy clay is _______ pounds per square foot. For bedrock it is ________ pounds per square foot.
1500 / 12,000
p184
Surface materials:
Test pits are usually up to a depth of about ____ feet.
8
p 184
Surface materials:
The use of a test pit permits the ________ of the soil to be observed and measured.
strata
p 184
- Identifiable layers of different soils.
Strata
p 184
Surface materials:
Test boring are used at depths ________ than those of test pits.
greater
p 184
Surface material
A test boring can provide information on the bearing capacity of soil through the use of a __________ __________.
driving hammer
p 184
Types of foundations
The main factors that determine the type of foundation to be used for a building are the ______ ____________ and the ____________ ______________.
soil conditions / structural configurations
p 185
Foundations are divided into two types: __________ and _______.
shallow and deep
p 185
A shallow foundation transfers the weight of the building to the soil at the ?
base of the building
p 185
A shallow foundation can be used where the ______-_________ ability of the soil directly under the building is adequate to support the building.
load-bearing
p 185
Shallow foundations usually make use of __________ to transmit the load to the soil.
footings
p 185
- That part of the building that rests on the bearing soil and is wider than the foundation wall.
Footing
p 185
The increased area of the footing reduces the _____________ stress on the soil.
compressive
p 185
A _______ __________ is a continuous strip of concrete that supports a wall.
wall footing
p 185
- Square pad of concrete that supports a column.
Column Footing
p 186
- Footing consisting of layers of beams placed at right angles to each other and usually encased in concrete.
Grillage Footing
p 186
When the load bearing capacity of the soil beneath a building is low, the footing must be large in area and a ______ ____________ may be used.
mat foundation
p 186
- Thick slab beneath the entire area of building.
Mat Foundation
p 186
A mat foundation differs from a simple floor slab in its ___________ and amount of ______________.
thickness / reinforcement
p 186
A mat may be several ______ thick and heavily reinforced, whereas a slab may only be a ______ thick.
feet / foot
p 186
- Foundation for which the volume of earth excavated will approximately equal the weigh of the building supported. Thus, the total weight supported by the soil beneath the foundation remains about the same, and settlement is minimized because of the weight of the building.
Floating foundation
p 187
Deep foundations are more ________ than shallow foundations, so are used only where shallow foundations cannot be used.
costly
p 187
Deep foundations take the form of either _______ or ______.
piles or piers
p 187
_______ are driven into the ground and develop their load carrying ability either through friction with the surrounding soil or by being driven into contact with rock or a load bearing soil layer.
Piles
p 187
Piles can be ________, _______ or ________ concrete.
timber, steel or precast
p 187
_______ are constructed by first drilling or digging a shaft and then filling it with concrete.
Piers
p 187
When a pier is designed with a footing, it is known as a “________” pier.
“belled”
p 187
The _________ is the protective sleeve used to keep water out of the excavation for the pier.
caisson
p 187
On a steep slope piles or piers are driven to act as __________ ____________ to resist the lateral force of the building. The vertical elements are connected with a _____ _______.
vertical cantilevers / tie beam
p 188
When a building is to have a ___________, the foundation must include walls to enclose it.
basement
p 189
___________ is the material most commonly used for foundation walls.
Concrete
p 189
Concrete is durable and is resistant to ___________ and ________.
moisture and insects
p 189
A layer of ____________ ____________ is sometimes placed on the outside of foundation walls for insulation.
expanded polystyrene (EPS)
p 190
Building settlement:
Movement may be downward as in the case of ____________, upward as in the case of _________, or outward as in the case of _________ _____________.
settlement / heaving / lateral displacement
p 190
______________ of foundation is the most frequent building movement.
Settlement
p 190
Settlement of a foundation can be either _________ or ___________.
uniform or differential
p 190
In ________ ___________, parts of a foundation settle at the same rate and misalignment between structural members is minor.
uniform settlement
p 190
____________ _____________ takes place when different parts of the foundation settle by different amounts.
Differential settlement
p 190
Situations may arise where it is necessary to strengthen and stabilize an existing foundation. This process is known as _____________.
underpinning
p 191
- Process of strengthening an existing foundation.
Underpinning
p 191
The terms shoring and underpinning are sometimes used interchangeably. However, _________ refers to temporary supports. ____________ refers to permanent supports.
shoring / underpinning
p 191
