National Urban Search & Rescue Response System
Structural Collapse Technician Training
Structural Collapse Technician
Training
Module : 4 - Part b
Lifting & Moving
Airbags
Lifting Considerations
& Stabilization
Calculating Weights
Jan08
27Jan09
SCT4- b Slide 1
National Urban Search & Rescue Response System
Structural Collapse Technician Training
High Pressure Air Bags
 Characteristics
Neoprene/butyl rubber
Steel kevlar reinforced
Variety of sizes
Maximum capacity is calculated at 1
inch of lift
Capacity reduced at max height
SCT4- b Slide 2
National Urban Search & Rescue Response System
Structural Collapse Technician Training
High Pressure Air Bags
 Application
Maximum stack of two high
Lift is limited to capacity of small bag
Larger bag on bottom
Centers of bags MUST be aligned
SCT4- b Slide 3
National Urban Search & Rescue Response System
Structural Collapse Technician Training
Airbag Lift
Animated Slide (10 seconds)
SCT4- b Slide 4
National Urban Search & Rescue Response System
Structural Collapse Technician Training
High Pressure Air Bags
LOAD
Increased surface area =
Increased lifting
capacity
COLUMN OF AIR
BASE OF SUPPORT
SCT4- b Slide 5
National Urban Search & Rescue Response System
Structural Collapse Technician Training
High Pressure Air Bags
LOAD
C
O
L
U
M
N
O
F
A
I
R
AIR BAG
INFLATED
REDUCED
SURFACE
AREA
CONTACT
BASE OF SUPPORT
SCT4- b Slide 6
National Urban Search & Rescue Response System
Structural Collapse Technician Training
High Pressure Air Bags
Dimension
6”x 6”
6”x 12”
10”x 10”
15”x 15”
15”x 21”
20”x 20”
24”x 24”
28”x 28”
36”x 36”
Capacity
1.5 Tons
3.2
4.8
12.0
17.0
21.8
31.8
43.8
73.4
Lift Ht.
3”
3.5
5
8
9
11
13
16
20
Weight
2 lbs
3
4
10
13
16
22
30
48SCT4- b Slide 7
National Urban Search & Rescue Response System
Structural Collapse Technician Training
High Pressure Air Bags
Manufacture’s I.D. Tag
SCT4- b Slide 8
National Urban Search & Rescue Response System
Structural Collapse Technician Training
High Pressure Air Bags & Cribbing
SCT4- b Slide 9
National Urban Search & Rescue Response System
Structural Collapse Technician Training
Spreading & Pushing
SCT4- b Slide 10
National Urban Search & Rescue Response System
Structural Collapse Technician Training
Lifting & Stabilizing Irregular Objects
SCT4- b Slide 11
National Urban Search & Rescue Response System
Structural Collapse Technician Training
Pipes & Cylinders
SCT4- b Slide 12
National Urban Search & Rescue Response System
Structural Collapse Technician Training
Inflating Air Bags
SCT4- b Slide 13
National Urban Search & Rescue Response System
Structural Collapse Technician Training
SCT4- b Slide 14
National Urban Search & Rescue Response System
Structural Collapse Technician Training
SCT4- b Slide 15
National Urban Search & Rescue Response System
Structural Collapse Technician Training
SCT4- b Slide 16
National Urban Search & Rescue Response System
Structural Collapse Technician Training
SCT4- b Slide 17
National Urban Search & Rescue Response System
Structural Collapse Technician Training
OOPS!
SCT4- b Slide 18
National Urban Search & Rescue Response System
Structural Collapse Technician Training
SCT4- b Slide 19
National Urban Search & Rescue Response System
Structural Collapse Technician Training
Lifting
Considerations
SCT4- b Slide 20
National Urban Search & Rescue Response System
Structural Collapse Technician Training
Lifting Or Moving A Load
Functions to be addressed
Center of Gravity
Load Stability
Wedges & cribbing
Estimating Load Weight
Lifting Functions
Critical angle
SCT4- b Slide 21
National Urban Search & Rescue Response System
Structural Collapse Technician Training
Center of Gravity & Load Stability
Unstable
Stable
CG
CG
Connection point
below CG makes
object unstable.
SCT4- b Slide 22
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Structural Collapse Technician Training
Wedges, Shims & Cribbing
SCT4- b Slide 23
National Urban Search & Rescue Response System
Structural Collapse Technician Training
Wedges
Wedge (mechanics)
Technically is a portable double inclined
plane, a wedge is a simple machine
used to separate two objects, or
portions of objects, through the
application of force, perpendicular to
the inclined surfaces, developed by
conversion of force applied to the blunt
end. The mechanical advantage of a
wedge depends on the ratio of its
length to its thickness.
SCT4- b Slide 24
National Urban Search & Rescue Response System
Structural Collapse Technician Training
Wedges
Use of wedges to
change direction
SCT4- b Slide 25
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“Marrying”
Wedges (repeated from 2b)
Sloped Surfaces Must Be in Full Contact
1” min.
Full Driven
Best
Over Driven
O.K.
Under Driven
Wrong
What if one wedge is Upside Down?
This is NOT RECOMMENDED.
It is better to have the cut surfaces
together – more friction & better fit
SCT4- b Slide 26
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Structural Collapse Technician Training
2x4 Wedges
2x4 wedges are often needed for smaller
adjustments than are possible with 4x4
wedges.
SCT4- b Slide 27
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Shims
 Shims are used to fill space,
opposed to wedges that lift, load or
charge objects.
SCT4- b Slide 28
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Shims
 Note that there are two shims in
this photo.
SCT4- b Slide 29
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Box Cribbing
6000 lbs. per contact point
Four point system
Nine point system
SCT4- b Slide 30
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Box Cribbing
TIER
3X
SCT4- b Slide 31
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Box Cribbing
2x
Solid
3x
4x
SCT4- b Slide 32
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Structural Collapse Technician Training
Box Cribbing
6000 lbs. per contact point
SCT4- b Slide 33
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Box Cribbing
Object
Must have
full bearing
with crib
Contact
Points
SCT4- b Slide 34
National Urban Search & Rescue Response System
Structural Collapse Technician Training
Box Cribbing
Least desirable layout
Each crib
is only
supporting
6000 lbs
Not very
stable
Height to
width
1 to 1
SCT4- b Slide 35
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Structural Collapse Technician Training
Box Cribbing
Can be as little as 1 to 1 with
angle situations
SCT4- b Slide 36
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Crib Stability
Load should be centered!
SCT4- b Slide 37
National Urban Search & Rescue Response System
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Crib Stability
LOAD
MUST
BE
CENTER
1/3 of
CRIB
SCT4- b Slide 38
National Urban Search & Rescue Response System
Structural Collapse Technician Training
Crib Stability
Load is not within mid-third at bottom
LOAD
MUST
BE
CENTER
1/3 of
CRIB
SCT4- b Slide 39
National Urban Search & Rescue Response System
Structural Collapse Technician Training
Change Angle
Use of wedges & shims
SCT4- b Slide 40
National Urban Search & Rescue Response System
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Martian Cribbing
SCT4- b Slide 41
National Urban Search & Rescue Response System
Structural Collapse Technician Training
Cribbing
SCT4- b Slide 42
National Urban Search & Rescue Response System
Structural Collapse Technician Training
Calculating Weights
SCT4- b Slide 43
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Weights of Building Materials
WIDTH x HEIGHT x LENGTH = CUBIC FT
 Reinforced concrete = 150 pcf
 Concrete columns & beams weigh more
(16”sq w/ 5% rebar = 170pcf)
 Steel = 490 pcf
 Use Area Method – later slides
 Earth = 100 to 125 pcf
 Wood = 35 pcf (dry) – use 40
SCT4- b Slide 44
National Urban Search & Rescue Response System
Structural Collapse Technician Training
Calculating Weight
Concrete Rectangle
WIDTH x HEIGHT x LENGTH x WEIGHT
4’ x 2 ’x 20’ = 160cf x 150pcf = 24,000 lbs.
4 feet
2 feet
20 feet
SCT4- b Slide 45
National Urban Search & Rescue Response System
Structural Collapse Technician Training
Calculating Weights
Concrete Round
0.8 DIAMETER2 x LENGTH x WEIGHT
0.8 x 3’ x 3’ x 20’ = 144cf x 150pcf = 21,600 lbs.
3 feet
20 feet
SCT4- b Slide 46
National Urban Search & Rescue Response System
Structural Collapse Technician Training
Calculating Weight
Concrete Pipe
Weight of Solid Round – Weight of Hole
0.8 (4’x 4’- 3’x 3’) x 20’x 150pcf
112 cu-ft x 150pcf = 16,800 lbs.
4 feet
diameter
6” thick
20 feet
SCT4- b Slide 47
National Urban Search & Rescue Response System
Structural Collapse Technician Training
Estimating Steel Weight - Area Method
 Steel weighs 490 lbs
per cubic ft
 Steel 1” thick weighs
490pcf / 12” = 40.8 psf
 For steel weight per
square foot use:
 1” thick
 ¾”
 ½”
 ¼”
12”
12”
12”
12”
12”
1”
Use 40 lbs
Use 30 lbs
Use 20 lbs
Use 10 lbs
SCT4- b Slide 48
National Urban Search & Rescue Response System
Structural Collapse Technician Training
Area Method Example - 1
 What is weight of this 36ft long steel section?
 2” Steel = 2 x 40 psf = 80 psf
 Area per ft = 2 x 3 sq ft + 2 x 1 sq ft = 8 sq ft
 Weight per ft = 8 x 80 = 640 plf
 Total weight = 640 x 36 = 23,040 lbs
 Exact weight = 652.8 plf (only 2% off)
Pl 36" x 2"
Pl 12" x 2" ea end
Pl 36" x 2"
SCT4- b Slide 49
National Urban Search & Rescue Response System
Structural Collapse Technician Training
Area Method Example - 2
 What is weight of this 20ft long steel section?
 2 Flanges 40 psf x 5” x 2 ft x 2 = 800 plf
 Web
40psf x 3.5” = 140
 Weight per ft = 800 + 140 = 940 plf
 Total weight = 940 x 20 = 18,800 lbs
 Exact weight = 958.8 plf (only 2% off)
Pl 24" x 5"
Pl 12" x 3.5”
Pl 24" x 5"
SCT4- b Slide 50
National Urban Search & Rescue Response System
Structural Collapse Technician Training
Calculate Steel Weight
SCT4- b Slide 51
National Urban Search & Rescue Response System
Structural Collapse Technician Training
Review & conclusion of Part b
 Review
 Airbags
 Lifting Considerations & Stabilization
 Calculating Weights
 Questions?
 Discussion?
 Next: Part c Cranes, Rigging & Bolting
SCT4- b Slide 52