Chapter 2: Foundations and Sitework

Question 1

What are the different loads on a foundation?

Answer 1

Live load: people, furniture (changes over time)
Dead load: the building itself (permanent/fixed)
Wind load: wind pressure

Question 2

Foundations must be economically and technically _____; it must not have adverse effects on the _____ structures.

Answer 2

Feasible; surrounding

Question 4

How do you classify earth materials?

Answer 4

1. Particle size
2. Moisture content
3. Presence of organic content

Question 5

May cause damages to finishes, cladding and other components where the building becomes distorted.

Answer 5

Differential settlement

Question 9

A dense, continuous mass of mineral materials that can be removed only by drilling, fracturing, or blasting. Strongest, most stable, and strength varies with mineral content and physical content.

Answer 9

Consolidated rock or bedrock

Question 10

Any earth material that is particulate

Answer 10

Soil

Question 11

Greater than 12 inches in diameter, must be picked up with two hands

Answer 11

Boulders

Question 12

Smaller than boulders, but greater than 3 inches in diameter, and can be picked up with one hand.

Answer 12

Cobbles

Question 13

Coarse-grained soils

Answer 13

Gravels and sands

Question 14

Spherical, less than 0.0029 inches, and is too small to be seen by the naked eye.

Answer 14

Silt

Question 15

Too small to be seen by the naked eye, smaller than silt, less than 0.0029 inches in diameter.

Answer 15

Clay

Question 16

Fine-trained soils

Answer 16

Silts and clay

Question 17

3 inches - 0.187 inches in diameter

Answer 17

Gravel

Question 18

0.187 inches - 0.003 inches, too small to be lifted individually

Answer 18

Sand

Question 19

Not suitable for the support of building foundations

Answer 19

Organic soils (peat, topsoil)

Question 20

Coarse-trained soils consist of relatively large mineral particles with _____ or _____ attractive or repulsive forces acting between them. They are not very affected by moisture content.

Answer 20

Little; no

Question 21

How are both coarse and fine-grained soils used for building construction?

Answer 21

Coarse-grained soils are stronger, while fine-grained soils fill in the gaps.

Question 22

Soils, when relying primarily on internal friction for strength.

Answer 22

Frictional/cohesionless

Question 23

Smaller-grained soils may be subject to a wide array of _____ forces.

Answer 23

Interparticle

Question 24

Spaces between the particles

Answer 24

Soil pores

Question 25

When water-saturated sands or silts lose virtually all of their strength and behave as a liquid when subjected to sudden, large changes in load, such as an earthquake.

Answer 25

Soil liquefaction

Question 26

Draining water away from foundations and substructures or from under slabs on grades and pavements.

Answer 26

Free draining

Question 27

Buildings will withstand better with highly-_____ soil.

Answer 27

Cohesive

Question 28

Material which is moldable when moist

Answer 28

Plastic

Question 29

Ability to sustain a higher moisture content before arriving at a flowable consistency

Answer 29

Liquid limit

Question 30

Range of particle sizes

Answer 30

Gradation

Question 31

Broad range of particle sizes

Answer 31

Well-graded

Question 32

Limited range of particle sizes, more void space and free draining

Answer 32

Poorly graded or "well sorted"

Question 33

Limited, narrow range of particle sizes

Answer 33

Uniformly graded

Question 34

Particle size distribution

Answer 34

Sorting

Question 35

Clay properties vary with moisture content and _____ composition. Some are highly expansive when wetted, some are virtually impervious to water, and some are subject to consolidation or gradual compression _____ _____.

Answer 35

Mineral; over time

Question 36

Generally, a larger particle size creates a _____ soil.

Answer 36

Stronger

Question 37

For raising the grade

Answer 37

General purpos fill

Question 38

Geotechnical reports describe _____ and their properties.

Answer 38

Soils

Question 39

Complex method to construct a steel-reinforced concrete wall many stories below the surface

Answer 39

Slurry wall

Question 40

Viscous mixture of water and bentonite clay

Answer 40

Slurry

Question 41

Beams that span across the face of the sheeting

Answer 41

Walers

Question 44

When crosslot bracing cannot be used because the excavation is too wide; bearing against temporary footings

Answer 44

Rakers

Question 45

Removal of water from the excavation or surrounding soil; removal from sumps.

Answer 45

Dewatering

Question 46

Pit where water accumulates; low points in excavation or surrounding soil

Answer 46

Sumps

Question 47

Depresses the water table

Answer 47

Well points

Question 48

Soils directly below the building substructure are _____ and _____.

Answer 48

Weak; unstable

Question 49

Used for small building design of foundations where soil analysis is unnecessary.

Answer 49

Allowable foundation pressures/allowable soil pressures

Question 50

When clay with high moisture content is put under continuous pressure, the water is pressed out of it causing a gradual reduction in soil volume.

Answer 50

Consolidation

Question 51

The water content at which the soil transitions from solid to plastic.

Answer 51

Plastic limit

Question 52

A _____ _____ may include recommendations for allowing bearing walls for various soil strata, appropriate foundation types, estimated rates of foundation settlement, soil drainage, foundation waterproofing, and other relevant information.

Answer 52

Geotechnical report

Question 53

Trees and plants, stumps, large roots, and other surface materials are removed with heavy machinery.

Answer 53

Grubbing and cleaning

Question 54

_____ is necessary for basement construction, to reach undistributed, adequately firm soil for shallow footings, for trenches for buried utilities, and to remove native soils that are contaminated or too weak or unstable to build over.

Answer 54

Excavation

Question 55

Sloped back; less expensive than sheeted excavation, requires a site without property lines, adjacent structures, or other limits on excavation.

Answer 55

Benched

Question 56

Angle low enough that the soil will not slide back into the hole; can be steep for cohesive soils such as stiff clays or shallower for frictional soils such as sand and gravel.

Answer 56

Maximum allowable slope/angle of repose

Question 57

Supports the sides of an excavation and prevent collapse

Answer 57

Shoring

Question 58

Steel columns driven vertically into the earth at close intervals around an excavation site. Braced by rakers, followed by waterproofing and cast in place concrete wall foundation.

Answer 58

H-piles/soldier beams

Question 59

Vertical sheets of various materials are aligned tightly against one another and driven (not drilled) into the earth to form a solid wall (most common: steel; but wood, aluminum, PVC plastic, composite polymers, or precast concrete can be used)

Answer 59

Sheet piling/sheeting

Question 60

Driven into earth

Answer 60

Piles

Question 61

Building g superstructure temporarily supported on cribbing while new foundation is built.

Answer 61

Underpinning

Question 62

Allows ground water to flow downward where it is collected by drain piping.

Answer 62

Drainage mat

Question 63

Draws water away from the substructure

Answer 63

Drain piping

Question 64

A moisture-resistant cement plaster or asphalt compound applied to basement walls where groundwater conditions are mild or waterproofing requirements are not critical.

Answer 64

Dampproofing

Question 65

Resists the passage of water even under more demanding conditions of hydrostatic pressure. It is more costly, and is used where groundwater conditions are severe or the need to protect subgrade space from moisture is critical.

Answer 65

Waterproofing

Question 66

Used instead of bracing; holes are drilled at intervals through the shoring and steel cables or rods are inserted, grouted in place, stretched tight, and fastened to the walers. Leave the excavation unencumbered.

Answer 66

Tiebacks

Question 68

Temporary steel wide-flame columns, which are driven into the earth at points where braces will cross

Answer 68

Crosslot bracing