Flashcards in Conventional Breaching (Chapter 11) Deck (36)

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1

## 23. What are Opposed Counter Force charges effective against?

### Effective against rectangular masonry or concrete columns 4’ thick or less

2

## 15. What is the rounding rule of breaching radius for External Charge?

### Round breaching radius UP to the nearest ½ foot

3

## If the amount of charge explosive is from 0 to less than 5 pounds, how thick would your charge be?

### 1 inches

4

## 20. If N is equal to 2.5 or greater, how many charges should be use?

### Round OFF to nearest whole number

5

## 12. If concrete block with uncertain material factor, how would you identified it as?

### Always assume as reinforced concrete

6

## 10. For External Charges, Breaching Radius is equal to ____

### The thickness of target

7

## 18. If N is less than 1.25, how many charges should be used?

### One charge

8

## 11. How would determine if target material cannot be identified?

### Assume target consists of strongest material in each specified groups

9

## 14. The size of tamping should be…

### Equal to or greater than Breaching Radius

10

## 1. What is purpose of conventional breaching?

### Used to destroy bridges, piers, abutements, and compound walls

11

## 17. What is the formula to find the number of charges?

###
N = W / (2R)

Number of charges = Width / (2 x Radius)

N = number of charges

W = width of pier, slab, or wall

R = breaching radius in feet

Use this formula in Step 5

12

## 16. What is the rounding rule of breaching radius for Internal Charge?

### Round breaching radius UP to the nearest ¼ foot

13

## 13. If you required to destroy a mason building with uncertain material, what will be the K (constant material factor)?

### Assume it as first class masonry

14

## 25. How much build up require to prime counter force charge?

### Blasting cap required ½” build up

15

## 22. What are the considerations of counterforce charges?

###
Charges should be diametrically opposed (explosive divided into 2 equal parts)

Obstacle must have at least 3 free faces or be freestanding

Relies on shockwave collision

Round measurements UP to next 1/2 foot (External charge)

16

## 2. What are the critical factors in conventional breaching? Which are most important?

###
Size, shape, placement, and tamping

Size and confinement are most critical factors

(charges will not cut rebar reinforcement)

17

## 3. What is the formula for breaching charges?

###
P = R^3 KC

(Pound = route 3 to Kansas City)

(Pound = Breaching Radius^3 x Constant for material factor x Tamping factor

18

## 6. If the amount of charge explosive is 40 pounds to less than 300 pounds, how thick would your charge be?

### 4 inches

19

## 24. What is the formula for a counterforce charge?

### Pounds = 1.5 x Breaching Radius

20

## 5. If the amount of charge explosive is 5 pounds to less than 40 pounds, how thick would your charge be?

### 2 inches

21

## 19. If N is greater than or equal to 1.25 and less than 2.5, how many charges should be used?

### Two charges

22

## 9. For Internal Charges, Breaching Radius is equal to ____

###
½ the thickness of the target (for charges placed at center mass)

Remaining thickness of the target not drilled if not placed at center of mass

23

## 7. If the amount of charge explosive is greater than 300 pounds, how thick would your charge be?

### 8 inches

24

## 21. A counterforce charge relies on what?

### Shockwave collision

25

## What is the intended effect when breaching?

### To create spalling

26

## Will charges cut rebar reinforcement?

### No, use P=D

27

## If a charge is 0 to less than 5 pounds, how thick should it be?

### 1 inch

28

## Define R in the breaching formula

### Breaching radius is the thickness of material needed to be destroyed

29

## Define K in the breaching formula

### The strength & hardness of the target material

30