1. Chapter 17
Cranes
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

2. MOBILE CRANES

3. CRANES
The crane is the primary machine used for the vertical movement of construction materials.

4. MOBILE CRANES
Boom
Mast
Counter weight
Boom stop

5. CRAWLER or WHEEL MOUNT

6. COMMON MOBILE CRANE TYPES
Telescoping-boom truck-mounted
Crawler
All-terrain
Lattice-boom truck-mounted
Cranes for heavy lift
Rough-terrain

7. CRAWLER CRANES
The full revolving super-structure of this type of unit is mounted on a pair of parallel crawler tracks. The crawlers provide the crane with good travel capability
around the job site.

8. CRAWLER CRANES
Large crawler crane with a rear mast

9. CRAWLER CRANES
Lattice-boom crawler crane rigged with a jib extension

10. CRAWLER CRANES
Rubber-track telescoping-boom crawler crane on an urban project

11. CRAWLER CRANES

12. CRAWLER CRANES

13. CRAWLER CRANES
Extendable counter-weight to increase lifting capacity

14. CRAWLER CRANES
Mobile crawler crane with tower attachment

15. CRAWLER CRANES Common dimensions Maximum boom length: 100 to 400 ft
Maximum fly-jib length: 30 to 120 ft
Maximum radius (boom only):
80 to 300 ft
Minimum radius: 10 to 15 ft

16. CRAWLER CRANES Common capacities:
Maximum lifting capacity (at minimum radius): 30 to 600 tons
Maximum travel speed: 50 to 100 ft/min (0.6 to 1.2 mph)
Ground bearing pressure: 7 to 20 psi

17. TELESCOPING-BOOM TRUCK-MOUNTED CRANES
Outriggers
These are truck cranes that have a self-contained telescoping
boom

18. TELESCOPING-BOOM TRUCK-MOUNTED CRANES
Outrigger on large steel mat to prevent damage to pavement
Outrigger on layered steel mats; note the dangerous ground deformation

19. TELESCOPING-BOOM TRUCK-MOUNTED CRANES
With extension jib
Raised on outriggers

20. TELESCOPING-BOOM TRUCK-MOUNTED CRANES
Point-load exerted by outrigger
Crane positioned on hollow-core precast concrete panels ceiling
Temporary panel support

21. TELESCOPING-BOOM TRUCK-MOUNTED CRANES
Common dimensions:
Maximum boom length: 70 to 170 ft
Maximum fly-jib length: 30 to 100 ft
Maximum radius (boom only):
60 to 140 ft
Minimum radius: 10 ft for most models

22. TELESCOPING-BOOM TRUCK-MOUNTED CRANES
Common capacities:
Maximum lifting capacity
(at minimum radius): 20 to 120 tons
Maximum travel speed: 40 to 70 mph
Number of axles: 3 to 4

23. LATTICE-BOOM TRUCK-MOUNTED CRANES
The lattice-boom structure is lightweight. This reduction in boom weight means additional lift capacity, as the machine predominately handles hoist load and less weight of boom.

24. LATTICE-BOOM TRUCK-MOUNTED CRANES

25. LATTICE-BOOM TRUCK-MOUNTED CRANES
Common dimensions:
Maximum boom length: 170 to 470 ft
Maximum fly-jib length: 4 0 to 300 ft
Maximum radius (boom only):
130 to 380 ft
Minimum radius: 10 to 25 ft

26. LATTICE-BOOM TRUCK-MOUNTED CRANES
Common capacities:
Maximum lifting capacity
(at minimum radius): 50 to 600 tons
Maximum travel speed: to 60 mph
Number of axles: 4 to 8

27. ROUGH-TERRAIN CRANES
These units are equipped with unusually large wheels and closely spaced axles to improve maneuverability at the job site.
They earn the right to their name by their high ground clearance, as well as the ability to move on steep slopes.

28. ROUGH-TERRAIN CRANES

29. ROUGH-TERRAIN CRANES Common dimensions:
Maximum boom length: 80 to 140 ft
Maximum fly-jib length: 20 to 90 ft
Maximum radius (boom only):
70 to 120 ft
Minimum radius: 10 ft for most models

30. ROUGH-TERRAIN CRANES Common capacities:
Maximum lifting capacity (at minimum radius): to 90 tons
Maximum travel speed: 15 to 35 mph
Number of axles: 2 for all models

31. ALL-TERRAIN CRANES
These cranes have an undercarriage capable of long-distance highway travel. Yet the carrier has all-axle drive and all-
wheel steering, crab steering, large tires, and high ground clearance.

32. ALL-TERRAIN CRANES Common dimensions:
Maximum boom length: 100 to 270 ft
Maximum fly-jib length: 30 to 240 ft
Maximum radius (boom only):
70 to 250 ft
Maximum radius (with fly jib):
100 to 300 ft (and up to 400 ft for the largest machines)
Minimum radius: 8 to 10 ft

33. ALL-TERRAIN CRANES Common capacities: Maximum lifting capacity
(at min. radius): 30 to 300 tons (and up to 800 tons)
Maximum travel speed: 40 to 55 mph
Number of axles: 2 to 6
(and up to 8 or 9)

34. CRAWLER CRANES FOR HEAVY-LIFTING
Additional counterweight mounted on a wheeled platform to increase lifting capacity

35. CRAWLER CRANES FOR HEAVY-LIFTING
Ring system (“ringer”): the heavy counterweight system is supported on a large circular turntable ring

36. SUITABILITY BUILDING PROJECTS: Low rise structures – short cycle times
High rise structures – long cycle times
High speed/high volume operations
(concrete placement)
Site conditions (position, locations)
Vertical reach requirements

37. SUITABILITY INDUSTRIAL PROJECTS: Very precise (one time hoists)
Heavy loads (possibly dual hoists)
Working around fixed objects
Site conditions (position, locations)
Vertical reach requirements

38. SUITABILITY HEAVY PROJECTS: Very precise (one time hoists)
Heavy loads (possibly dual hoists)
High speed/high volume
operations (concrete placement)
Multiple work locations
Site conditions (position, locations)
Vertical reach requirements

39. SUITABILITY
HEAVY PROJECTS:
Heavy loads (possibly dual hoists)

40. SAFETY OSHA Crane fatality data: Energized power lines 50%
Overturning 19%
Load dropped 14%
Boom collapsed 12%
Two-block %

41. SAFETY Crane Accidents: Overturning 61.0% Overload 12.5% Rigging 12.5%
Road accidents 10.0%

42. CRANE ACCIDENTS
Overturning 61.0%

43. CRANE ACCIDENTS Plan the work Work the plan
Success is the result of procedural detail performed with demanding discipline

44. SELECTION FACTORS Height of reach required Working envelope
Maximum load
Time
Duty cycle

45. HEIGHT OF REACH REQUIRED
Height load is to be lifted
Height of the load
Sling height
Hook block height
Size of the load

46. CONSIDER ALL HEIGHTS Hook Block Sling Height
Load Height
Height Load is to be Lifted

47. HEIGHT OF LOAD

48. SLING HEIGHT

49. HOOK BLOCK HEIGHT

50. SAFE LOAD LIFTING Hook Block Height 2 ft Sling Height 6 ft
You are tasked to place concrete into column forms using a bucket. The following information describes the lift.
Load Height (Bucket) ft
Hook Block Height ft
Sling Height ft
Load must be raised ft

51. Hook 2 ft
Sling 6 ft
Load 12 ft
Raised 25 ft
HEIGHT OF REACH
45 ft

52. CRANE MOTION The motions a mobile crane uses to move a load are:
1. Hoist
2. Swing
3. Boom Up/Boom Down
4. Travel
These are listed in descending order of fastest to slowest rate of motion.

53. CRAWLER CRANE SWING
A key aspect of crane capacity is quadrant of operation.
A track-mounted crane has three quadrants that are established by a radius running from the center of rotation through both the idler and final drive on each side of the crane or by lines parallel to the tracks.

54. RADIUS DEFINITION Over the drive end (back) Over the Side
Over the idler end (front)

55. RADIUS DEFINITION Over the drive end (back) Over the Side
Over the idler end (front)

56. FRONT or BACK?
Drive end (back)

57. RATED LOADS FOR CRAWLER CRANES
Load capacity depends on the quadrant position of the boom with respect to the machine’s undercarriage. In the case of crawler cranes, the quadrants that should be considered are:
Over the side
Over the drive end of tracks
Over the idler end of tracks

58. WHEEL-MOUNTED CRANE SWING
A wheel-mounted crane has three quadrants that are established by a radius running from the superstructure center of rotation through the outrigger support on each side of the crane.

59. Over the side
Over the front L C
Over the rear
Over the side

60. RATED LOADS FOR WHEEL-MOUNTED CRANES
Quadrants of consideration will vary with the configuration of the outrigger locations.

61. RATED LOADS FOR WHEEL-MOUNTED CRANES
For 4 outriggers, the three quadrants to consider are usually defined by imaginary lines running from the super- structure center of rotation through the position of the outrigger support:
Over the side
Over the rear of the carrier
Over the front of the carrier

62. LOAD CHART Crane size Operating radius Boom length Boom height (angle)
Maximum capacity rear
Maximum capacity side

63. LOAD CHART
Some load charts give load capacity based on quadrant of operation; others give a 360 degree rating.

64. STABILITY Counterweight and Load superstructure Short distance
Load distance

65. STABILITY
Short distance
Load distance

66. LEVERAGE

67. MAXIMUM LOAD Cranes may fail by two different mechanisms: Stability
Table 17.2 loads appearing below the solid line.
Structural capacity

68. LOAD CHART
Load charts usually specify the boom and boom top for the load ratings, examples:
Boom No. 22A or No. 22C with open throat top.
77 SA Hammerhead Boom

69. BOOMS
Angular
Tubular

70. RATED LOAD
For a crawler crane rated load is 75% of tipping load.

71. RATED LOAD
For a carrier-mounted crane on outriggers rated load is 85% of tipping load.

72. RATED LOAD
For a carrier-mounted crane on rubber rated load is 85% of tipping load.

73. MAXIMUM LOAD
Stability (tipping)
Proper use of outriggers
Ground conditions
Level

74. MAXIMUM LOAD
Proper use of outriggers

75. Proper use of outriggers

76. OUTRIGGERS ON CITY STREETS

77. KEEP IT LEVEL
Mats may be required

78. MAXIMUM LOAD
Structural capacity: At short radii capacity may depend on boom or outrigger strength. Whether the load is limited by tipping or other factors will be noted on the load chart.
Table 17.2, above the line is controlled by other factors.

79. MAXIMUM LOAD
Table 17.2, above the line is controlled by other factors.

81. MAXIMUM LOAD NET HOISTING CAPACITY (LOAD WEIGHT) = GROSS CAPACITY
DEDUCTIONS
Deductions differ between crane manufacturers and with crane types.

82. COMMON DEDUCTIONS Weight of hook & headache ball
Weight of slings & rigging

83. ADD ALL WEIGHTS HOOK BLOCK WEIGHT GROSS CAPACITY SLING WEIGHT
NET CAPACITY

84. COMMON DEDUCTIONS
Weight of wire rope from tip sheave to auxiliary hook
Weight of auxiliary hook

85. COMMON DEDUCTIONS Is the jib being used?
Then look up a different load chart.

86. COMMON DEDUCTIONS
Weight of stowed jib

87. SAFE LOAD
You are to place beams on a bridge project using a crane w/180 ft of boom.
LOAD WEIGHT ,200 lb
HOOK BLOCK WT ,250 lb
SLING WEIGHT lb
HEIGHT OF LIFT ft
LOAD ft
HOOK ft
SLING ft
OPERATING RADIUS ft

88. MAXIMUM LOAD (35,200 lb + 3,225 lb) DEDUCTIONS: 3,225 lb
Gross Capacity must be greater than: 38,425 lb
(35,200 lb + 3,225 lb)

89. LIFTING HEIGHT
LIFT ft
LOAD ft
HOOK ft
SLING ft
TOTAL 156 ft

90. SAFE HOIST
At a radius of 40 ft, gross capacity must be greater than 38,425 lb.
CHECK following chart

93. SAFE HOIST
At a radius of 40 ft, gross capacity must be greater than 38,425 lb.
from the chart
47, ft
Elev. Boom point ft
Therefore lift is OK.

94. HOIST ANALYSIS LOAD HEIGHT 16 ft LOAD WT 35,200 lb
SLING HEIGHT 10 ft SLING WT lb
HOOK BK HT _4 ft HOOK BK WT 2,250 lb
LIFT HEIGHT 126 ft ADDITIONAL WT 0
TOTAL HT ft TOTAL WT ,425lb
CRANE SIZE tn
OPERATING RAD. 40 ft
BOOM HEIGHT ft
BOOM LENGTH ft
BOOM ANGLE º