steel cutting charges action: calculate and place steel cutting charges. conditons: given a 2 hour...
TRANSCRIPT
STEEL CUTTING CHARGES
ACTION: Calculate and place steel cutting
charges.
CONDITONS: Given a 2 hour block of instruction,
students handout, FM 5- 250, and Demolition
Card GTA 5-10-33.
STANDARD: Students will correctly calculate and
place steel cutting charges.
SAFETY: Specific safety considerations will be
discussed where appropriate throughout the
lesson.
SPECIAL CONSIDERATIONS
• Target Configuration– Structured Steel
• Target Materials– High-Carbon Steel– Alloy Steel– Cast Iron
• Type of Explosives• Size of Explosives
Pg. 3-10
PLACEMENT OF CHARGESplit the charge
• Continuous• Contact• Width• Priming
Charge is placed on the side of target Charge is split in half
Placed opposite side of each otherOffset the web thickness
Pg. 3-11
BLOCK CHARGES
P = 3/8 A
P = pounds of TNT
3 / 8 = Constant
A = area of cross section of target in square inches
Pg. 3-12
BLOCK CHARGEBLOCK CHARGEwalk throughwalk through
Cut each I-Beams 1 time, using C-4Flanges 16 x 1, Web 12 x .55 Beams
BLOCK SOLUTIONStep 1 : Flanges = 16 x 1 x 2, Web = 12 x .5
1 cut, C-4, 5 BeamsStep 2 : Flanges = 16 x 1 x 2 = 32 Sq in
Web = 12 x .5 = 6 Sq in TOTAL = 38 Sq in
P = 3/8 x 38 = 14.25 lbs TNTStep 3 : 14.25 = 10.63 lbs C4 (M112) 1.34Step 4 : 10.63 = 8.5 1.25Step 5 : 5 Beams x 1 cut = 5 Charges
Step 6 : 9 x 5 = 45 pkgs C4 (M112)
9 pkgs C4 (M112)
Step 1 : Flanges = 15 x 1 x 2 = 30 Sq inWeb = 12 x 1 = 12 Sq in
TOTAL = 42 Sq in
Step 2 : P = 3/8 A P = 3/8 x 42 = 15.75 lbs TNT
Step 3 : 15.75 = 11.75 lbs C4 (M112) 1.34
Step 4 : 11.75 = 9.4 10 pkgs C4 (M112) 1.25
Step 5 : 4 Beams = 4 Charges
Step 6 : 10 x 4 = 40 pkgs C4 (M112)
BLOCK SOLUTION # 1BLOCK SOLUTION # 1
19.5” x 2”19.5” x 2”
19.5” x 2.5”19.5” x 2.5”
14” x 1.5”14” x 1.5”
How many packages of C-4are required to cut the 15 beams shown using a block charge
BLOCK CHARGE
STEP 1 : Given: C4, 15 I-beams Flanges 19.5 x 2 = 3919.5 x 2.5 = 48.75
14 x 1.5 = 21 Total Area = 108.75
STEP 2: P = 3/8A .375 x 108.75 =40.78 lbs TNT
STEP 3: 40.78 / 1.34 = 30.43 lbs C4
STEP 4: 30.43 / 1.25 = 24.34 Pkg C4 25 pkgs C4
STEP 5: 15 Beams = 15 charges
STEP 6: 25 x 15 = 375 pkgs C-4 (M112)
AverageThickness
ofSection
(in)
Pounds of Explosive (TNT) for Rectangular steel sections of given Dimensions
Height of Section (in)
2 3 4 5 6 7 8 9 10 11 12 141/4
17/83/45/81/23/8
0.20.30.40.50.60.70.8
222016 18 242.33.4
4.55.76.87.9
9
2.13.1
4.25.26.37.3
8.3
1.92.8
3.84.75.76.6
7.5
1.72.63.44.35.16
6.8
1.52.3 33.84.55.3
6
1.3 22.73.3 44.6
5.3
1.21.72.32.93.4 4
4.5
1.11.62.12.73.13.7
4.2
11.41.92.42.83.3
3.8
0.91.91.72.22.63
3.4
0.81.21.51.92.32.7
3
0.71.11.41.7 22.4
2.7
0.60.91.21.41.72
2.3
0.30.50.60.70.91
1.2
0.40.60.8 11.21.4
1.5
0.50.7 11.21.41.7
1.9
NOTE: to use this table –1. Measure each rectangular section of total member separately.2. Find the appropriate charge size for the rectangular section from the table. If the section dimension is not listed in the table, use the next-larger dimension.3. Add the individual charges for each section to obtain the total charge weight.
1/2
10
1.9
AverageThickness
ofSection
(in)
Pounds of Explosive (TNT) for Rectangular steel sections of given Dimensions
Height of Section (in)
2 3 4 5 6 7 8 9 10 11 12 141/4
17/83/45/81/23/8
0.20.30.40.50.60.70.8
222016 18 242.33.4
4.55.76.87.9
9
2.13.1
4.25.26.37.3
8.3
1.92.8
3.84.75.76.6
7.5
1.72.63.44.35.16
6.8
1.52.3 33.84.55.3
6
1.3 22.73.3 44.6
5.3
1.21.72.32.93.4 4
4.5
1.11.62.12.73.13.7
4.2
11.41.92.42.83.3
3.8
0.91.91.72.22.63
3.4
0.81.21.51.92.32.7
3
0.71.11.41.7 22.4
2.7
0.60.91.21.41.72
2.3
0.30.50.60.70.91
1.2
0.40.60.8 11.21.4
1.5
0.50.7 11.21.41.7
1.9
NOTE: to use this table –1. Measure each rectangular section of total member separately.2. Find the appropriate charge size for the rectangular section from the table. If the section dimension is not listed in the table, use the next-larger dimension.3. Add the individual charges for each section to obtain the total charge weight.
1/2
16
3
How many packages of C4, (M112)
are required to cut 5 I-beams with
dimensions of 8” x 1/2” for the flanges,
9” x 1” for the web ?
HASTY PROBLEM # 1HASTY PROBLEM # 1
HASTY SOLUTION # 1HASTY SOLUTION # 1Step 1 : [8” x 1/2”] [9” x 1”] [8” x 1/2”]
Table ValueStep 2 : 8” x 1/2” 1.2 lbs
9” x 1” 2.9 lbs8” x 1/2” 1.2 lbsTotal = 5.3 lbs C4
Step 3 : N/A
Step 4 : 5.3 = 4.24 5 Pkgs C4 (M112)1.25
Step 5 : 5 beams = 5 charges
Step 6 : 5 x 5 = 25 pkgs C4 (M112)
RIBBON CHARGE• Step 2. Calculate the volume of explosives.
– T x W x L = volume of explosives in cu. in. needed– T = Charge thickness = 1/2 TGT but never less than
1/2 inch– W = Charge width = 3 times the charge thickness– L = Charge length = length of TGT to be cut
• Step 4. Calculate packages of C4 or M118– C4: 1” x 2” x 10” = 20 cu inches– M118 sheet: .25” x 3” X 12” = 9 cu inches
• 4 SHEETS = 1 M118 PACKAGE (use in Step 6)
• Maximum target thickness = 3 inches Pg. 3-15
RIBBON CHARGE PLACEMENT
Thickness of chargeThickness of charge= 1/2 thickness of TGT= 1/2 thickness of TGTWidth of charge Width of charge
= 3 times thickness= 3 times thicknessof chargeof charge
Length of chargeLength of charge= length of TGT= length of TGT
Place ½ inch explosive Place ½ inch explosive around around cap or knotcap or knot
Primed at center Primed at center with a blasting cap with a blasting cap or det cord knotor det cord knot
Det Cord orDet Cord orTime FuseTime Fuse
Pg. 3-16
Beams Beams >> 2” thick 2” thickoffset flange charge:offset flange charge:Edge to EdgeEdge to Edge
Det Cord branch lines are all of equal lengths forming a (British Junction)
Beams < 2” thickBeams < 2” thickoffset flange charge:offset flange charge:Edge to CenterEdge to Center
Charge Thickness = 1/2 Thickness of the target never less than .5
RIBBON CHARGE
Charge thickness (T)
Charge thickness (T)
Charge width3 x T
Charge width3 x T
Charge width3 x T
Charge lengthFL - WT =L
Charge lengthFL - WT =L
Charge lengthWL - TCT - BCT= L
Required explosiveT x W x L=VOL
Required explosiveT x W x L=VOL
Required explosiveT x W x L=VOL
Charge thickness (T)
TOTALEXPLOSIVES
T W L
TF
WEB
BF
RIBBON CHARGE WALK THROUGHRIBBON CHARGE WALK THROUGH
How much C4 (M112) is required to cut How much C4 (M112) is required to cut one plate?one plate?
24”
2”
Step 1. 2” x 24”
Step 2. 1” x 3” x 24” = 72 cu. in.
Step 3. N/A
Step 4. 72 = 3.6 4 pkgs C-4 (M112)
20
Step 5. 1 Plate = 1 charge
Step 6. 4 x 1 = 4 pkgs C-4 (M112)
RIBBON CHARGE WALK THROUGHRIBBON CHARGE WALK THROUGH
19.5” x 2”19.5” x 2”
19.5” x 2.5”19.5” x 2.5”
14” x 1.5”14” x 1.5”
How many packages of C-4are required to cut the 15 beams shown using a ribbon charge
RIBBON CHARGE
STEP 1 : Given: C4, 15 I-beams Flanges 19.5 x 219.5 x 2.5
Web 14 x 1.5
STEP 2: T x W x L = VOL cu. in. of explosivesTF 1 x 3 x 18 = 54Web .75 x 2.25 x 11.75 = 19.82BF 1.25 x 3.75 x 18 = 84.37
TOTAL VOL = 158.19
STEP 3: N/A
STEP 4: 158.19 = 7.90 20
8 pkgs C-4 (M112)
STEP 5: 15 Beams = 15 chargesSTEP 6: 8 x 15 = 120 pkgs C-4 (M112)
19.5”
14”
2”
RIBBON CHARGE PROBLEM #2
RIBBON CHARGE PROBLEM #2
2”
2”
Use Use (M118 sheet (M118 sheet explosive)explosive)
15 Beams15 Beams
STEP 1 : Given: M118, 15 I-beamsSTEP 2: T = 1” W = 3” L = Top Flange = 19.5” - 2” = 17.5” Bottom Flange = 19.5” - 2” = 17.5”
Web = 14” - 2” = 12” TOTAL = 47”
T x W x L = 1”x 3” x 47” = 141 cu. in. of explosivesSTEP 3: N/ASTEP 4: 141 = 15.66 16 sheets (M118)
9STEP 5: 15 Beams = 15 chargesSTEP 6: 16 x 15 = 240 sheets (M118)
4 = 60 packages (M118)
RIBBON CHARGE PROBLEM #2 SOLUTION
RIBBON CHARGE PROBLEM #2 SOLUTION
8”
16”
1.5”
RIBBON CHARGE PROBLEM #3
RIBBON CHARGE PROBLEM #3
1.5”
Use Use M118M11812 12 BeamsBeams
1.5”
STEP 1 : Given: M118, 12 I-beams
STEP 2: T = .75” W = 2.25” L = Top Flange = 8” - 1.5” = 6.5”
Bottom Flange = 8” - 1.5” = 6.5” Web = 16” - 1.5” = 14.5”
TOTAL = 27.5”
T x W x L = .75” x 2.25” x 27.5” = 46.4 cu. in. of explosives
STEP 3: N/A
STEP 4: 46.4 = 5.15 6 sheets M118
9
STEP 5: 12 Beams = 12 charges
STEP 6: 6 x 12 = 72 sheets
4 sheets per pkg = 18 pkgs M118
RIBBON CHARGE PROBLEM #3 SOLUTION
RIBBON CHARGE PROBLEM #3 SOLUTION
SUMMARYBLOCK CHARGEBLOCK CHARGE
Placement and PrimingPlacement and PrimingFormula methodFormula methodTable methodTable method
RIBBON CHARGERIBBON CHARGEPlacement and Priming Placement and Priming FormulaFormula
M118M118Round to SHEET in step 4Round to SHEET in step 4Round to PACKAGE in step 6Round to PACKAGE in step 6