BAILEY BRIDGE EXAM 2025 with questions and
verified answers with rationale
SECTION A: SITE LAYOUT AND RECONNAISSANCE (Questions 1–25)
1. What is the first consideration when selecting a Bailey bridge crossing site?
A) Proximity to supply routes
B) Width of the gap and soil conditions on both banks
C) Availability of crane support
D) Time of day
Answer: B) Width of the gap and soil conditions on both banks
Rationale: Site selection must account for gap width, soil bearing capacity, and terrain on both banks
before any assembly planning can begin -9.
2. How is the initial bridge length determined?
A) Width of the gap only
B) Gap width plus safety setbacks plus roller clearances
C) Standard 100-foot increments
D) Panel count multiplied by 10
Answer: B) Gap width plus safety setbacks plus roller clearances
Rationale: The initial length accounts for the actual gap, the safety setback distances on each bank,
and space for the launching rollers -1-12.
3. Which two points are used to measure the gap between two unprepared abutments?
A) Top of slope
B) Toe of slope
C) Center of stream
D) Waterline
Answer: B) Toe of slope
Rationale: Measuring at the toe of slope accounts for the unstable material that may slough off the
bank, ensuring the bridge spans the stable foundation -7-12.
4. What is the required safety setback on an unprepared abutment if the bank height is 6 feet?
A) 6 feet
B) 9 feet
C) 12 feet
D) 3 feet
Answer: B) 9 feet
Rationale: The formula is 1.5 × bank height. For a 6-foot bank: 1.5 × 6 = 9 feet. This ensures the
bridge seat rests on stable soil, not on the unstable slope face -1-7-12.
5. What is the safety setback on an unprepared abutment with a bank height of 7 feet?
A) 7 feet
B) 10.5 feet
C) 14 feet
D) 21 feet
,Answer: B) 10.5 feet
Rationale: 1.5 × 7 = 10.5 feet, applying the same safety setback formula -12-13.
6. Where are all measurements taken from for the rollers during site layout?
A) Edge of roller to edge of next roller
B) Center of roller to center of next roller
C) Top of roller to top of next roller
D) Outside diameter of roller to outside diameter of next roller
Answer: B) Center of roller to center of next roller
Rationale: All roller spacing measurements are taken center-to-center to ensure consistent bay
lengths and proper bridge geometry -1-7-12.
7. What is the center-to-center roller spacing?
A) 10 feet
B) 12 feet 6 inches
C) 14 feet 10 inches
D) 25 feet
Answer: C) 14 feet 10 inches
Rationale: The standard center-to-center roller spacing for Bailey bridge construction is 14 feet 10
inches -1-7.
8. What is the longitudinal spacing between plain rollers?
A) 10 feet
B) 14 feet 10 inches
C) 25 feet
D) 30 feet
Answer: C) 25 feet
Rationale: Plain rollers are spaced at 25-foot longitudinal intervals along the launch path -1-12.
9. How far should the extra set of plain rollers (construction rollers) be placed temporarily behind
the rocking rollers when determining longitudinal spacing?
A) 6 feet
B) 10 feet
C) 12½ feet
D) 25 feet
Answer: C) 12½ feet
Rationale: Construction rollers are placed 12½ feet behind the rocking rollers to aid in inserting
launching-nose links and provide clearance -1-7-12.
10. What is the purpose of construction rollers?
A) Support the bridge during decking
B) Aid in inserting the launching-nose links and provide clearance between the links and the ground
C) Replace rocking rollers temporarily
D) Level the bridge during jacking
Answer: B) Aid in inserting the launching-nose links and provide clearance between the links and
the ground
Rationale: Construction rollers serve a specialized purpose during nose assembly and launch
preparation -1-7.
, 11. On soft soil, what is used under the base plates to distribute the load?
A) Concrete pads
B) Timber grillage
C) Steel plates
D) Gravel
Answer: B) Timber grillage
Rationale: FM 5-277 specifies timber grillage under base plates on soft soil to spread bearing
pressure -2.
12. What is the maximum slope between banks of different elevations for Bailey bridge assembly?
A) 10 to 1
B) 20 to 1
C) 30 to 1
D) 50 to 1
Answer: C) 30 to 1
Rationale: The bridge can be assembled between banks of different elevations, but the slope should
not exceed 30 to 1 -2.
13. How many rocking rollers are needed for a 150-foot TS bridge on the near and far banks?
A) 2 near, 2 far
B) 3 near, 3 far
C) 4 near, 2 far
D) 4 near, 4 far
Answer: C) 4 near, 2 far
Rationale: The near bank requires 4 rocking rollers while the far bank requires 2 for this
configuration -12-13.
14. What determines the number of unloading parties needed?
A) Bridge length and type
B) Number of personnel available
C) Time of day
D) Soil conditions
Answer: A) Bridge length and type
Rationale: Unloading party requirements scale with the quantity of bridge components, which
depends on length and construction type (SS, DS, TS, etc.) -1.
15. How many unloading parties are needed for a 100-foot DS bridge?
A) 3
B) 4
C) 5
D) 6
Answer: C) 5 unloading parties
Rationale: A 100-foot Double-Single bridge requires 5 unloading parties to efficiently handle the
component volume -1-7.
16. What is the maximum span achievable with standard Bailey bridge equipment (M2)?
A) 150 feet
B) 180 feet
C) 210 feet
D) 250 feet
verified answers with rationale
SECTION A: SITE LAYOUT AND RECONNAISSANCE (Questions 1–25)
1. What is the first consideration when selecting a Bailey bridge crossing site?
A) Proximity to supply routes
B) Width of the gap and soil conditions on both banks
C) Availability of crane support
D) Time of day
Answer: B) Width of the gap and soil conditions on both banks
Rationale: Site selection must account for gap width, soil bearing capacity, and terrain on both banks
before any assembly planning can begin -9.
2. How is the initial bridge length determined?
A) Width of the gap only
B) Gap width plus safety setbacks plus roller clearances
C) Standard 100-foot increments
D) Panel count multiplied by 10
Answer: B) Gap width plus safety setbacks plus roller clearances
Rationale: The initial length accounts for the actual gap, the safety setback distances on each bank,
and space for the launching rollers -1-12.
3. Which two points are used to measure the gap between two unprepared abutments?
A) Top of slope
B) Toe of slope
C) Center of stream
D) Waterline
Answer: B) Toe of slope
Rationale: Measuring at the toe of slope accounts for the unstable material that may slough off the
bank, ensuring the bridge spans the stable foundation -7-12.
4. What is the required safety setback on an unprepared abutment if the bank height is 6 feet?
A) 6 feet
B) 9 feet
C) 12 feet
D) 3 feet
Answer: B) 9 feet
Rationale: The formula is 1.5 × bank height. For a 6-foot bank: 1.5 × 6 = 9 feet. This ensures the
bridge seat rests on stable soil, not on the unstable slope face -1-7-12.
5. What is the safety setback on an unprepared abutment with a bank height of 7 feet?
A) 7 feet
B) 10.5 feet
C) 14 feet
D) 21 feet
,Answer: B) 10.5 feet
Rationale: 1.5 × 7 = 10.5 feet, applying the same safety setback formula -12-13.
6. Where are all measurements taken from for the rollers during site layout?
A) Edge of roller to edge of next roller
B) Center of roller to center of next roller
C) Top of roller to top of next roller
D) Outside diameter of roller to outside diameter of next roller
Answer: B) Center of roller to center of next roller
Rationale: All roller spacing measurements are taken center-to-center to ensure consistent bay
lengths and proper bridge geometry -1-7-12.
7. What is the center-to-center roller spacing?
A) 10 feet
B) 12 feet 6 inches
C) 14 feet 10 inches
D) 25 feet
Answer: C) 14 feet 10 inches
Rationale: The standard center-to-center roller spacing for Bailey bridge construction is 14 feet 10
inches -1-7.
8. What is the longitudinal spacing between plain rollers?
A) 10 feet
B) 14 feet 10 inches
C) 25 feet
D) 30 feet
Answer: C) 25 feet
Rationale: Plain rollers are spaced at 25-foot longitudinal intervals along the launch path -1-12.
9. How far should the extra set of plain rollers (construction rollers) be placed temporarily behind
the rocking rollers when determining longitudinal spacing?
A) 6 feet
B) 10 feet
C) 12½ feet
D) 25 feet
Answer: C) 12½ feet
Rationale: Construction rollers are placed 12½ feet behind the rocking rollers to aid in inserting
launching-nose links and provide clearance -1-7-12.
10. What is the purpose of construction rollers?
A) Support the bridge during decking
B) Aid in inserting the launching-nose links and provide clearance between the links and the ground
C) Replace rocking rollers temporarily
D) Level the bridge during jacking
Answer: B) Aid in inserting the launching-nose links and provide clearance between the links and
the ground
Rationale: Construction rollers serve a specialized purpose during nose assembly and launch
preparation -1-7.
, 11. On soft soil, what is used under the base plates to distribute the load?
A) Concrete pads
B) Timber grillage
C) Steel plates
D) Gravel
Answer: B) Timber grillage
Rationale: FM 5-277 specifies timber grillage under base plates on soft soil to spread bearing
pressure -2.
12. What is the maximum slope between banks of different elevations for Bailey bridge assembly?
A) 10 to 1
B) 20 to 1
C) 30 to 1
D) 50 to 1
Answer: C) 30 to 1
Rationale: The bridge can be assembled between banks of different elevations, but the slope should
not exceed 30 to 1 -2.
13. How many rocking rollers are needed for a 150-foot TS bridge on the near and far banks?
A) 2 near, 2 far
B) 3 near, 3 far
C) 4 near, 2 far
D) 4 near, 4 far
Answer: C) 4 near, 2 far
Rationale: The near bank requires 4 rocking rollers while the far bank requires 2 for this
configuration -12-13.
14. What determines the number of unloading parties needed?
A) Bridge length and type
B) Number of personnel available
C) Time of day
D) Soil conditions
Answer: A) Bridge length and type
Rationale: Unloading party requirements scale with the quantity of bridge components, which
depends on length and construction type (SS, DS, TS, etc.) -1.
15. How many unloading parties are needed for a 100-foot DS bridge?
A) 3
B) 4
C) 5
D) 6
Answer: C) 5 unloading parties
Rationale: A 100-foot Double-Single bridge requires 5 unloading parties to efficiently handle the
component volume -1-7.
16. What is the maximum span achievable with standard Bailey bridge equipment (M2)?
A) 150 feet
B) 180 feet
C) 210 feet
D) 250 feet
