# STEEL CUTTING CHARGES ACTION: Calculate and place steel cutting charges. CONDITONS: Given a 2 hour block of instruction, students handout, FM ,

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STEEL CUTTING CHARGES ACTION: Calculate and place steel cutting charges. CONDITONS: Given a 2 hour block of instruction, students handout, FM , and Demolition Card GTA 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 Target configurations of steel in structures determine the amount of explosive required for successful destruction. Target material can influence type of explosive Structured steel / I-Beams, L-Beams, channel and structural steel Ts and plates High carbon / vary dense usually metal working dies and rolls Alloy steel / Gears, Shafts, tools, chain and cables Cast iron / rail road items and pipes (vary brittle easily broken) Nickel-molybdenum / cannot be cut easily with conventional steel cutting charges. (multiple charges or linear shaped charges or using some other form other than explosive) Type of explosive / C4 or M118 sheet are best used by cutting can occur with TNT using block methods Size of explosive / some explosive cannot be molded and may not make contact with target alternative Pg. 3-10

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 The Charge is CONTINUOUS over the complete line of the proposed cut There is close CONTACT between the charge and the target and the blocks within the charge The WIDTH of the charge’s cross section is between ONE to THREE times its THICKNESS MAX 6” Long charges are primed every 4 to 5 feet or every 4th block of C-4 Place the charge ALL on one side unless the charge extends past the flange, Then you would split the charge in half and place then on opposite sides of the target offset the thickness of the web 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 P = Pounds of TNT, so if you use anything other than TNT you must use step three 3/8 = is a constant Area of the cross section of the target in square inches. Pg. 3-12

AREA OF CROSS SECTION Flanges Web
Figure the area of each separately and add them for the total area

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

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 = 32 Sq in Web = 12 x = 6 Sq in TOTAL = 38 Sq in P = 3/8 x 38 = lbs TNT Step 3 : = lbs C4 (M112) Step 4 : = 9 pkgs C4 (M112) Step 5 : 5 Beams x 1 cut = 5 Charges Step 6 : 9 x 5 = 45 pkgs C4 (M112)

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

BLOCK SOLUTION # 1 Step 1 : Flanges = 15 x 1 x 2 = 30 Sq in Web = 12 x = 12 Sq in TOTAL = 42 Sq in Step 2 : P = 3/8 A P = 3/8 x 42 = lbs TNT Step 3 : = lbs C4 (M112) Step 4 : = pkgs C4 (M112) Step 5 : 4 Beams = 4 Charges Step 6 : 10 x 4 = 40 pkgs C4 (M112) Explain step one. Emphasize the rounding rule in step 4 and the location.

How many packages of C-4 are required to cut the
15 beams shown using a block charge 19.5” x 2” 19.5” x 2.5” 14” x 1.5” Have the students remember this PE to compare to ribbon charge calculation on exact same Beams

BLOCK CHARGE STEP 1 : Given: C4, 15 I-beams Flanges 19.5 x 2 = 39
Total Area = STEP 2: P = 3/8A .375 x =40.78 lbs TNT STEP 3: / 1.34 = lbs C4 STEP 4: / 1.25 = Pkg C4 25 pkgs C4 Remember 375 Packages to cut 15 I-Beams Transition: With most calculations in Demo, there is normally an way you can get similar results by using a table that has already been calculated for you. For steel cutting BLOCK charges, there are two tables you can use, depending on what type of explosives you have available. The first one we will look at is the TNT Table STEP 5: 15 Beams = 15 charges STEP 6: 25 x 15 = 375 pkgs C-4 (M112)

NOTE: to use this table –
Average Thickness of Section (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 10 11 12 14 16 18 20 22 24 1/4 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.5 1.7 1.9 2.1 2.3 3/8 0.3 0.5 0.6 0.7 0.9 1.1 1.2 1.9 1.4 1.6 1.7 2 2.3 2.6 2.8 3.1 3.4 1/2 1/2 0.4 0.6 0.8 1 1.2 1.4 1.5 1.7 1.9 1.9 2.1 2.3 2.7 3 3.4 3.8 4.2 4.5 5/8 0.5 0.7 1 1.2 1.4 1.7 1.9 2.2 2.4 2.7 2.9 3.3 3.8 4.3 4.7 5.2 5.7 3/4 0.6 0.9 1.2 1.4 1.7 2 2.3 2.6 2.8 3.1 3.4 4 4.5 5.1 5.7 6.3 6.8 7/8 0.7 1 1.4 1.7 2 2.4 2.7 3 3.3 3.7 4 4.6 5.3 6 6.6 7.3 7.9 1 0.8 1.2 1.5 1.9 2.3 2.7 3 3.4 3.8 4.2 4.5 5.3 6 6.8 7.5 8.3 9 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. This Table is for TNT only It’s results is in POUNDS If the dimension of the steel you’re cutting isn’t on the table, USE THE NEXT HIGHER dimension that appears on the table. Figure each section of the target separately then add them for the total per cut Example: ½” thick by 10” results in 1.9 pounds of TNT for this section

NOTE: to use this table –
Average Thickness of Section (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 14 16 16 18 20 22 24 1/4 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.5 1.7 1.9 2.1 2.3 3/8 0.3 0.5 0.6 0.7 0.9 1.1 1.2 1.9 1.4 1.6 1.7 2 2.3 2.6 2.8 3.1 3.4 1/2 1/2 0.4 0.6 0.8 1 1.2 1.4 1.5 1.7 1.9 2.1 2.3 2.7 3 3 3.4 3.8 4.2 4.5 5/8 0.5 0.7 1 1.2 1.4 1.7 1.9 2.2 2.4 2.7 2.9 3.3 3.8 4.3 4.7 5.2 5.7 3/4 0.6 0.9 1.2 1.4 1.7 2 2.3 2.6 2.8 3.1 3.4 4 4.5 5.1 5.7 6.3 6.8 7/8 0.7 1 1.4 1.7 2 2.4 2.7 3 3.3 3.7 4 4.6 5.3 6 6.6 7.3 7.9 1 0.8 1.2 1.5 1.9 2.3 2.7 3 3.4 3.8 4.2 4.5 5.3 6 6.8 7.5 8.3 9 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. Example: 7/16” Thick use ½” table dimension 15” Wide use 16” table dimension Resulting in 3 pounds TNT required for this section The other table you may have to use is for C-4 only. It reads the same way and the results are in pounds of C-4.

HASTY BLOCK CHARGE Table 3-3, pg 3-12: TNT
1. Measure rectangular sections separately. 2. Use table to find pounds of explosives for each section. Table 3-3, pg 3-12: TNT 3. Add charges from each section to find total charges. 4. If dimensions of sections are not on table, use the larger dimension.

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 ?

HASTY SOLUTION # 1 Step 1 : [8” x 1/2”] [9” x 1”] [8” x 1/2”] Table Value Step 2 : 8” x 1/2” lbs 9” x 1” lbs 8” x 1/2” lbs Total = lbs C4 Step 3 : N/A Step 4 : = Pkgs C4 (M112) Step 5 : 5 beams = 5 charges Step 6 : 5 x 5 = 25 pkgs C4 (M112) Review and explain.

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 Ribbon Charges are considered a SPECIAL CHARGE. Special Charges are used to calculate for the MINIMUM amount of explosives you can use to attack a target. Special charges normally take longer to calculate and place than other charges, but the payoff is the significantly less amount of explosives for the charge. For Ribbon and other special charges use C-4 and Sheet explosives only The results of this calculation are in CUBIC INCHES if explosives. Pg. 3-15

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

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

Thickness of the target never less than .5 Beams > 2” thick
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)

Charge Thickness (T) Target thickness

RIBBON CHARGE T W L Charge thickness (T) Charge length FL - WT =L
Charge width 3 x T Required explosive T x W x L=VOL 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

RIBBON CHARGE WALK THROUGH
How much C4 (M112) is required to cut one plate? 2” 24” Give the critical information. Ribbon charge. 24 x 2 C-4 1 plate

RIBBON CHARGE WALK THROUGH
Step 1. 2” x 24” Step 2. 1” x 3” x 24” = 72 cu. in. Step 3. N/A Step = pkgs C-4 (M112) 20 Step Plate = 1 charge Step x 1 = 4 pkgs C-4 (M112) review

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

RIBBON CHARGE STEP 1 : Given: C4, 15 I-beams Flanges 19.5 x 2
Web x 1.5 STEP 2: T x W x L = VOL cu. in. of explosives TF x x = 54 Web x x = BF x x = TOTAL VOL = STEP 3: N/A STEP 4: = 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 PROBLEM #2
19.5” 14” 2” 2” Use (M118 sheet explosive) 15 Beams Give the critical information. Ribbon charge. 19.5 x 2 = = 17.5 19.5 x 2 = = 17.5 or x 2 = 35 14 x 2 = =12 or =12 C-4 15 Beams 2”

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 = sheets (M118) 9 STEP 5: 15 Beams = 15 charges STEP 6: 16 x 15 = 240 sheets (M118) 4 = 60 packages (M118) Explain step 3.

RIBBON CHARGE PROBLEM #3
8” 16” 1.5” Use M118 12 Beams 1.5” Give the critical information. Ribbon charge. 8 x 1.5 = = 6.5 8 x 1.5 = = 6.5 or x 2 = 13 16 x1.75 = = 14.5 or = 14.5 M118 12 Beams 1.5”

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 = ” T x W x L = .75” x 2.25” x 27.5” = cu. in. of explosives STEP 3: N/A STEP 4: = sheets M118 9 STEP 5: 12 Beams = 12 charges STEP 6: 6 x 12 = 72 sheets 4 sheets per pkg = 18 pkgs M118 Explain steps 3, 4 and 6.

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

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