Chpt 6 Flashcards
The function of a______is to transfer the structural load of a building to the ground
Foundation
The use of a test pit usually used up to a depth of about 8 feet. The use of a test pit permits the ____ of the soil to be observed and measured
Strata
The allowable foundation pressure for sandy clay is
1500 pounds per square foot
For bedrock the allowable foundation pressure is
12,000 per square foot
A ____ can provide information on the bearing capacity of soil through the use of a driving hammer
Test boring
The main factors that determine the type of foundation to be used for a building are the soil conditions and structural configuration other factors include the following
The work space available
Environmental factors
Impact on adjacent property
Building codes and regulations
A_____ transfers the weight of the building to the soil at the base of the building.
Shallow foundations
Penetrate layers of soil directly under a building to reach soil at a greater depth that can support the weight of the building
Deep foundations
Shallow foundations usually make use of ____ to transmit the load to the soil
Footings
A _____ is a widened base at the bottom of a column or foundation wall
Footing
A _____ is a continuous strip of concrete that supports a wall
Wall footing
A ____ is a square pad of concrete that supports a column
Column footing
A ____ consists of layers of beams placed at right angles to each other that are usually encased in concrete
Grillage footing
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
A ____ is a thick slab beneath the entire area of a building
Mat foundation
In some cases where the soil strength is low, a type of foundation known as a ____ may be used
Floating foundation
A _____ is the same as a mat foundation except that it is located beneath a building at a depth such that the weight of the soil removed is equal to the weight of the building
Floating foundation
Are more costly than shallow foundations, so are used only where shallow foundation cannot be used
Deep foundations
Take the form of either piles or piers
Deep foundations
Are driven into the ground and develop their load carrying ability either through friction with surrounding soil or by being driven into contact with rock or a load bearing soil layer
Piles
Are constructed by first drilling or digging a shaft and then filling it with concrete
Piers
When a pier is designed with a footing, it is known as a
Belled pier
Piers are often sometimes referred to as
Caissons
More accurately, the _____ is the protective sleeve used to keep water out of the excavation for the pier.
Caisson
When a building is to have a basement, the foundation must include ____ to enclose it
Walls
Concrete is the material most commonly used for
Foundation walls
Is the most frequent building movement
Settlement of foundations
In_____, parts of a foundation settle at the same rate and misalignment between structural members is minor
Uniform settlement
Takes place when different parts of the foundation settle by different amounts
Differential settlement
Differential settlement of a foundation can result from several conditions
Nonuniform soil conditions under the foundation
Footings or different sizes
Footings places at different elevations
Unequal loads on footings
Situations may arise where it is necessary to strengthen and stabilize and existing foundation. This process is known as
Underpinning
Refers to temporary support
Shoring
Refers to permanent support
Underpinning
The placement of shoring and underpinning is difficult and often dangerous work. It frequently involves excavation by hand because it may not be possible to position power equipment when the work is done in limited spaces such as basement. If a collapse occurs in connection with this work the fire department typically is called upon to conduct a
Rescue operations
