RSP Crane Types & Operational Limits 1 — Questions and Answers
Question 1: Which crane type uses a horizontal boom that can rotate 360 degrees and is mounted on a wheeled carrier?
- Tower crane
- Mobile hydraulic crane (Correct answer)
- Overhead bridge crane
- Gantry crane
Correct answer: Mobile hydraulic crane
A mobile hydraulic crane is mounted on a wheeled carrier with a boom that can rotate 360 degrees, allowing repositioning without dismantling.
Question 2: What document specifies the maximum load a crane can lift at various radii and boom angles?
- OSHA 1926.1412 inspection form
- Crane load chart (Correct answer)
- Lift plan form
- Manufacturer assembly manual
Correct answer: Crane load chart
The crane load chart (also called a capacity chart) specifies the maximum allowable load at each combination of radius, boom length, and configuration.
Question 3: A crawler crane differs from a mobile crane primarily because it:
- Uses a hydraulic boom instead of a lattice boom
- Travels on tracks instead of rubber tires (Correct answer)
- Cannot rotate the superstructure past 180 degrees
- Requires outriggers to be deployed before lifting
Correct answer: Travels on tracks instead of rubber tires
Crawler cranes travel on steel tracks (crawlers), which distribute load over a larger footprint and allow movement while under load.
Question 4: When operating a crane near its maximum rated capacity, the operator should primarily consult:
- The signal person's hand signals only
- The load chart for the exact boom length and radius (Correct answer)
- The previous day's inspection checklist
- The crane manufacturer's website
Correct answer: The load chart for the exact boom length and radius
The load chart provides the exact rated capacity for the current boom length, radius, and crane configuration, which must be followed to prevent overloading.
Question 5: What is the primary purpose of outriggers on a mobile crane?
- To increase the boom length for greater reach
- To stabilize the crane and increase its lifting capacity (Correct answer)
- To anchor the crane to the ground permanently
- To lower the center of gravity during transport
Correct answer: To stabilize the crane and increase its lifting capacity
Outriggers extend from the crane's lower works to provide a wider, more stable base, which increases tipping resistance and allows higher lifting capacities.
Question 6: Which of the following crane configurations typically has the highest rated lift capacity for a given boom length?
- Boom fully extended with no counterweight
- Shorter boom length with full outriggers extended and maximum counterweight (Correct answer)
- Longest boom angle near vertical with no outriggers
- Fly section attached with reduced counterweight
Correct answer: Shorter boom length with full outriggers extended and maximum counterweight
A shorter boom with full outriggers deployed and maximum counterweight installed provides the most stable configuration, yielding the highest rated capacity.
Question 7: A tower crane's maximum load capacity is typically reduced when the load is lifted at:
- A shorter radius close to the mast
- A longer radius farther from the mast (Correct answer)
- Maximum height with the hook at full elevation
- Minimum hook height near the ground
Correct answer: A longer radius farther from the mast
As the load radius (horizontal distance from the mast) increases on a tower crane, the rated capacity decreases because the bending moment on the jib increases.
RSP Crane Types & Operational Limits 1
Which crane type uses a horizontal boom that can rotate 360 degrees and is mounted on a wheeled carrier?