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Flashcards in Site Work Deck (69)
1

soil is classified into these 4 gorups

sands/gravels
silts
clays
organics

2

this soil has low plasticity, good for foundations/drainage

sands/gravel

3

this soil is good for foundations if stable

clay

4

this soil is better mixed with other types of soil

clay

5

this soil has tensile strength, and is slightly plastic

clay

6

this soil is a poor foundation

organics

7

an unbroken mixture of clay, sand, and gravel

hardpan

8

highest bearing capacity

bedrock

9

broken off bedrock

boulders

10

second highest bearing capacity

shale/slate

11

soft rock with a fine texture

shale/slate

12

a soil test typically determines

bearing capacity,
water table level,
porosity

13

administers soil test

soils engineer

14

typically recorded in boring log

material/ depth it is encountered/ moisture content/
density

15

boring location: minimum #

4, taken at corners

16

boring locations are shown on

plot plan

17

boring location #'s on plot plan correspond to

boring logs in soil test report

18

soils report contains

allowed soil bearing pressure and foundation type

19

lab tests:
specific gravity

determines void ratio,
used for compressibility

20

lab tests:
grain size and shape

determines shear strength,
permeability,
compaction ability

21

lab tests:
liquid and plastic limits

compaction and compressibility

22

lab tests:
unconfined compression

shear strength for cohesive soil

23

lab tests:
water content

used to get compressibility,
and compaction values for cohesive soil

24

most common site tests

boring,
and
test pit

25

most common borehole test

SPT

(Standard Penetration Test)

26

SPT tests

density of granular soils
and consistency of some clays

27

physical tools and process for SPT

2”ø sampler /
140lb hammer /
falling 30”.

28

recorded in SPT:
# blows required to

drive cylinder 12”

29

site test:
visual inspection,
10’ depth limit typ.

Test Pits

30

site test:
best in sand/clay
shallow/intermediate depths
no hard obstructions (bedrock/hardpan)

Auger Boring

31

site test:
when soil too hard for auger bit
100’+

Wash Borings

32

problem with wash borings

samples too mixed, analysis difficult

33

site test:
pipe, 5” increments

Dry Sample Borings

34

site test:
Soil Load Tests

platform,
incremental loads,
settlement holds,
with continued loading.
design load usually ½ test load

35

site test: Soil Load Tests
design load is typically ____

½ test load

36

soil types are classified by

Unified Classification System

37

bearing capacity is generally specified by ______ ,
based on ______

building code,
based on soil type

38

building code bearing capacity can be increased if

appropriate test evidence

39

water in soil can

reduce load carrying capacity

40

if more moisture under one area of building than another

differential settlement may occur

41

soil treatment is used to

increase bearing capacity, and/or decrease settlement

42

in order to compact fill,

water is required to lubricate

43

optimum relationship between fill density/moisture content
determined in lab by

Proctor test

44

“standards for compaction.”

Proctor test

45

Fill compaction:
density ___% of optimum Proctor density req’d

90-100%

46

Fill compaction:
moisture content __% of optimum @ time of compaction.

2-4%

47

Fill compaction:
fill in ____” layers (called ‘lifts’), compacted, then next layer.

8-12"

48

Soil Treatment:
Surcharging

preload with fill / settle soil below / remove fill.

49

Soil Treatment:
Mixing

sand/gravel added to create req’d properties.

50

Earthwork:
term for when narrow/long for pipe/narrow footings

trenching

51

Excavation:
for safety, sides no steeper than

than natural angle of repose
or not > 1.5H:1V

52

Rough Grading tolerance

±6-12” of desired finish level

53

Finish Grading tolerance

±1” desired level, includes placement of topsoil

54

Parts of Beam and Timber shoring method

soldier beams/
breast boards or cribbing/
tiebacks

55

Parts of Sheating and Brace shoring method

Vertical sheeting (wood/steel)/
horizontal wales,
diagonal rakers (bracing),
concrete/steel heel.

56

Underpinning is used when

temp. supporting exist'g foundations

57

perforated drain tile (“french drain”) min _” below floor slab

6"

58

if hydrostatic pressure use

layer of gravel
open web matting/
geotextile mat’l

59

if pressure @ floorlab use

use waterproofing membrane,
gravel layer w/ drain tiles.

60

min. slope of ground for drainage

1/4" per ft.

61

drain inlet vs. catch basin

catch basin has sump,
cleaned out periodically.

62

large storm sewers require manholes,

every direction change or 500 ft max.

63

Concrete paving is reinformed with

welded wire fabric

64

Concrete paving min. thickness

5" min.

65

Concrete paving poured in sections, w/ joints every

20’ (½” molded joint filler)

66

hot-laid asphalt:

most common
asphalt cement + graded aggregates,
laid on a base, rolled + compacted while still hot.

67

cold-laid asphalt:

subbase coarse gravel, overlaid w/ finer aggregate, compacted, rolled.
2-3” cold liquid asphalt laid over-top.

68

Unit paver procedure

laid on level, compacted sand over crushed gravel
may also be laid over bituminous bed on concrete slab.

69

Concrete Walks: laid over gravel subbase, control joints every _’, expansion joints every _’

control joints every 5’,
expansion joints every 20’