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STEEL CUTTING CHARGES

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.

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STEEL CUTTING CHARGES

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  1. 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.

  2. SPECIALCONSIDERATIONS • Target Configuration • Structured Steel • Target Materials • High-Carbon Steel • Alloy Steel • Cast Iron • Type of Explosives • Size of Explosives Pg. 3-10

  3. PLACEMENT OF CHARGE Split the charge • Continuous • Contact • Width • Priming Charge is placed on the side of target Charge is split in half Placed opposite side of each other Offset the web thickness Pg. 3-11

  4. 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

  5. AREA OF CROSS SECTION Flanges Web

  6. BLOCK CHARGEwalk through Cut each I-Beams 1 time, using C-4 Flanges 16 x 1, Web 12 x .5 5 Beams

  7. BLOCK SOLUTION Step 1 : Flanges = 16 x 1 x 2, Web = 12 x .5 1 cut, C-4, 5 Beams Step 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 TNT Step 3 : 14.25 = 10.63 lbs C4 (M112) 1.34 Step 4 : 10.63 = 8.5 1.25 9 pkgs C4 (M112) Step 5 : 5 Beams x 1 cut = 5 Charges Step 6 : 9 x 5 = 45 pkgs C4 (M112)

  8. BLOCK CHARGE #1 15 X 1 Use C4 Total of 4 beams 12 X 1 15 X 1

  9. BLOCK SOLUTION # 1 Step 1 : Flanges = 15 x 1 x 2 = 30 Sq in Web = 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)

  10. 19.5” x 2” 14” x 1.5” 19.5” x 2.5” How many packages of C-4 are required to cut the 15 beams shown using a block charge

  11. BLOCK CHARGE STEP 1 : Given: C4, 15 I-beams Flanges 19.5 x 2 = 39 19.5 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 25 pkgs C4 STEP 4: 30.43 / 1.25 = 24.34 Pkg C4 STEP 5: 15 Beams = 15 charges STEP 6: 25 x 15 = 375 pkgs C-4 (M112)

  12. Average Thickness of Section (in) Pounds of Explosive (TNT) for Rectangular steel sections of given Dimensions Height of Section (in) 4 8 9 20 22 24 2 3 5 7 10 11 12 14 16 10 6 18 1/4 2.1 2.3 0.2 1.1 1.2 1.3 1.7 1.9 1.5 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 3.4 2.8 3.1 0.3 1.6 1.7 2 2.6 3/8 2.3 0.5 0.6 0.7 0.9 1.1 1.2 1.9 1.4 1/2 1/2 0.4 2.1 2.3 2.7 3.4 4.2 3.8 4.5 3 0.6 0.8 1 1.2 1.4 1.5 1.7 1.9 1.9 5/8 0.5 4.7 5.2 5.7 2.7 2.9 3.3 4.3 3.8 0.7 1 1.2 1.4 1.7 1.9 2.2 2.4 3/4 0.6 3.1 3.4 4 5.1 5.7 6.3 6.8 4.5 0.9 1.2 1.4 1.7 2 2.3 2.6 2.8 3.7 4 4.6 6 7/8 0.7 6.6 7.3 7.9 5.3 1 1.4 1.7 2 2.4 2.7 3 3.3 1 0.8 9 4.2 4.5 5.3 6.8 8.3 7.5 6 1.2 1.5 1.9 2.3 2.7 3 3.4 3.8 • NOTE: to use this table – • Measure each rectangular section of total member separately. • 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.

  13. Average Thickness of Section (in) Pounds of Explosive (TNT) for Rectangular steel sections of given Dimensions Height of Section (in) 4 8 9 20 22 24 2 3 5 7 10 11 12 14 16 16 6 18 1/4 2.1 2.3 0.2 1.1 1.2 1.3 1.7 1.9 1.5 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 3.4 2.8 3.1 0.3 1.6 1.7 2 2.6 3/8 2.3 0.5 0.6 0.7 0.9 1.1 1.2 1.9 1.4 1/2 1/2 0.4 2.1 2.3 2.7 3.4 4.2 3.8 4.5 3 3 0.6 0.8 1 1.2 1.4 1.5 1.7 1.9 5/8 0.5 4.7 5.2 5.7 2.7 2.9 3.3 4.3 3.8 0.7 1 1.2 1.4 1.7 1.9 2.2 2.4 3/4 0.6 3.1 3.4 4 5.1 5.7 6.3 6.8 4.5 0.9 1.2 1.4 1.7 2 2.3 2.6 2.8 3.7 4 4.6 6 7/8 0.7 6.6 7.3 7.9 5.3 1 1.4 1.7 2 2.4 2.7 3 3.3 1 0.8 9 4.2 4.5 5.3 6.8 8.3 7.5 6 1.2 1.5 1.9 2.3 2.7 3 3.4 3.8 • NOTE: to use this table – • Measure each rectangular section of total member separately. • 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.

  14. HASTY PROBLEM # 1 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 ?

  15. HASTY SOLUTION # 1 Step 1 : [8” x 1/2”] [9” x 1”] [8” x 1/2”] Table Value Step 2 : 8” x 1/2” 1.2 lbs 9” x 1” 2.9 lbs8” x 1/2” 1.2 lbs Total = 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)

  16. 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

  17. RIBBON CHARGE PLACEMENT Thickness of charge = 1/2 thickness of TGT Width of charge = 3 times thickness of charge Primed at center with a blasting cap or det cord knot Length of charge = length of TGT Det Cord or Time Fuse Place ½ inch explosive around cap or knot Pg. 3-16

  18. < 2 inches offset edge to center WEB > 2 inches offset flange charges edge to edge

  19. Charge Thickness = 1/2 Thickness of the target never less than .5 Beams > 2” thick offset flange charge: Edge to Edge Beams < 2” thick offset flange charge: Edge to Center Det Cord branch lines are all of equal lengths forming a (British Junction)

  20. Charge Thickness (T) Target thickness

  21. RIBBON CHARGE T W L Charge length FL - WT =L Charge thickness (T) Required explosive T x W x L=VOL Charge width 3 x T TF Charge thickness (T) Charge width 3 x T Charge length WL - TCT - BCT = L Required explosive T x W x L=VOL WEB Charge thickness (T) Charge width 3 x T Charge length FL - WT =L Required explosive T x W x L=VOL BF TOTAL EXPLOSIVES

  22. RIBBON CHARGE WALK THROUGH How much C4 (M112) is required to cut one plate? 2” 24”

  23. RIBBON CHARGE WALK THROUGH 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)

  24. 19.5” x 2” 14” x 1.5” 19.5” x 2.5” How many packages of C-4 are required to cut the 15 beams shown using a ribbon charge

  25. STEP 1 : Given: C4, 15 I-beams Flanges 19.5 x 2 19.5 x 2.5 Web 14 x 1.5 STEP 2: T x W x L = VOL cu. in. of explosives TF 1 x 3 x 18 = 54 Web .75 x 2.25 x 11.75 = 19.82 BF 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 charges STEP 6: 8 x 15 = 120 pkgs C-4 (M112) RIBBON CHARGE

  26. 19.5” 14” 2” RIBBON CHARGE PROBLEM #2 2” Use (M118 sheet explosive) 15 Beams 2”

  27. RIBBON CHARGE PROBLEM #2 SOLUTION STEP 1 : Given: M118, 15 I-beams STEP 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 explosives STEP 3: N/A STEP 4: 141 = 15.66 16 sheets (M118) 9 STEP 5: 15 Beams = 15 charges STEP 6: 16 x 15 = 240 sheets (M118) 4 = 60 packages (M118)

  28. 8” 16” 1.5” RIBBON CHARGE PROBLEM #3 Use M118 12 Beams 1.5” 1.5”

  29. RIBBON CHARGE PROBLEM #3 SOLUTION 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

  30. SUMMARY • BLOCK CHARGE • Placement and Priming • Formula method • Table method • RIBBON CHARGE • Placement and Priming • Formula • M118 • Round to SHEET in step 4 • Round to PACKAGE in step 6

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