1. 1 Crane Selection and Application

2. 2 Introduction This presentation was developed as a teaching aid with the support of the American Institute of Steel Construction. It is primarily intended to be used by Construction Management programs to supplement classes in Construction Methods and Construction Equipment but also provides examples applicable to Estimating, Soils, Statics and Structures. The presentation materials would also be applicable in Architecture and Civil Engineering programs. This presentation contains several interactive Macros. You will need to enable Macros in PowerPoint to use these functions. Because viruses are sometimes transmitted through Macros, the default security setting for PowerPoint is usually High. This must be changed to Medium before opening the presentation. The security setting can be changed by first closing the presentation. In PowerPoint select Tools|Macro|Security… Select Medium. Reopen this presentation and select Enable Macros when prompted by the Security Warning. See the Slide Notes for additional information

3. 3 Crane Selection and Application Crane Types Crane Selection Crane Capability Evaluation Crane Use Optimization Estimate of Crane Costs Jobsite Methods and Management

4. 4 Types of Cranes Crawler Lattice All Terrain Truck Mounted Rough Terrain Tower Crane Types See also [1], 53-66, 78-81

5. 5 Rough Terrain Designed for un- improved work sites Roadable for short distances Four steering modes Pick and carry capability Three position outriggers

6. 6 Truck Mounted Can be driven at highway speeds Limited off-road capability Can do multiple jobs in one day Hydraulic booms allow fast setup but the weight (compared to lattice) reduces lifting capability

7. 7 All Terrain Combines features of Rough Terrain and Truck Mounted cranes Off-road capable All-wheel steering Highway speeds

8. 8 Crawler Lattice High-capacity, long- reach lifts Pick and carry operations Multiple attachments provide great flexibility in boom configuration

9. 9 Tower Used when space is at a premium Up and over reach Moving counterweight balances load Fixed foundation or Crawler w/attachment

10. 10 Crane Selection Selection criteria Crane data sheet examples –Rough Terrain - Grove RT700E –Crawler Lattice - Manitowoc Model 777 Manufacturer web sites

11. 11 Crane Selection Criteria Available space Working range Load charts Crane availability Number of lifts

12. 12 Available Space Can crane fit on jobsite? Can crane maneuver as required on jobsite? Can the boom configuration reach all required placement positions? Can boom avoid existing obstacles while performing required movements?

13. 13 Available Space

14. 14 Working Range Working range diagram shows the crane’s reach Load capacity will be significantly reduced at long radii Diagram also shows range of boom angles and attachment geometry

15. 15 Load Charts Load charts provide the authoritative load capacity for all crane configurations at all ranges Load Chart NOTES must be followed Weight of the block, rigging equipment and cable below the boom must be subtracted from load capacity to determine actual payload

16. 16 Crane Availability As with most types of construction equipment, the theoretically optimal crane for the job based on capability may not be readily available, or a more capable crane that is owned by the steel erector may be more economical Availability will always be an important factor in crane selection

17. 17 Number of Lifts Fixed costs for crane mobilization will be more significant for smaller jobs requiring fewer days on site A crane that can perform all lifts from a small number of positions (or a single position) on the job site may be highly desirable even if mobilization and operating cost are higher

18. 18 Crane Data Sheets Specifications Dimensions and weights Working range Load charts Notes to load charts

19. 19 Rough Terrain Hydraulic Crane Grove RT700E –50-60 ton capacity at 12 ft radius –36 ft – 110 ft, 4 section, full power boom –33 ft – 56 ft bifold lattice swingaway extension –20 ft or 40 ft extension inserts –12,150 lbs counterweight pinned to superstructure

20. 20 Critical RT700E Dimensions

21. 21 Critical RT700E Dimensions

22. 22 RT700E Weights Crane weight is critical when hauling The counterweight may have to be removed and transported on a separate vehicle

23. 23 Selected RT700E Specifications

24. 24 RT700E Working Range

25. 25 RT700E Capacity Calculator

26. 26 RT700E Load Chart (pounds)

27. 27

28. 28 Crawler Lattice Crane Manitowoc Model 777 –200 ton capacity at 13’ –270 ft, Heavy-Lift Boom (HLB) –300 ft Fixed Jib on HLB –350 ft Luffing Jib on HLB –Self assembly –Ships on 8 trucks

29. 29 Selected Specifications

30. 30 Model 777 Dimensions (w/o Boom)

31. 31 Model 777 Dimensions

32. 32 Model 777 Working Range

33. 33 Selected Model 777 Load Charts

34. 34 Model 777 Load Chart (kips)

35. 35 Links to Manufacturer’s Web Pages http://www.groveworldwide.com http://www.linkbelt.com http://www.terex.com http://www.tadanoamerica.com

36. 36 Crane Capability Evaluation Select crane position(s) Calculate distance to –Member staging area(s) –Member locations Check load capacity at each range – identify critical lifts Insure that crane can reach each location with previously placed members in place Consider multiple lift rigging

37. 37 Crane Positions Level, solid foundation –Provided by controlling contractor, as required by OSHA Adequate set back from slopes Consider addition of surcharge load to earth pressure on walls Protection of underground utilities/ structures Interference with other construction operations

38. 38 Plan for Crane Positions

39. 39 Office Building Case Study Consider the Office Building Case Study [2] available from the AISC Digital Library The steel erection was performed using a Manitowoc 222 crane stationed in two different positions Multiple lift rigging was employed to improve efficiency and reduce operator fatigue Since the heaviest members weigh about 3000 lbs the crane choice will be governed by the distance to the far corner

40. 40 Four Story Steel Frame

41. 41 Erecting Second Sequence

42. 42 Position Relative to Building

43. 43 Multiple Lift Rigging

44. 44 Roof Framing Plan 90’-8” Crane Center Pin Approx. 40’ 60’-4”

45. 45 Example Governing Lift Evaluation Distance to column C.G. is Weight of 33’-6” W12X45 with attachments is determined from detailer’s calculations (~1700 lbs) A 19 ton capacity weight ball and wire rope for hoisting weigh 1000 lbs. The crane load chart must be checked to insure that is has adequate capacity for the total load of 2700 lbs The Manitowoc Model 222 with 160’ Boom and 40’ Jib at 0° Offset can lift 4400 lbs at 150 foot radius The erection sequence must be checked to insure that the crane boom won’t strike other members

46. 46 Capability Evaluation Example Consider the Office Building Case Study Assume that two cranes are available –Grove RT700E –Manitowoc Model 777 Select a crane location Some details from the actual building were simplified in the model

47. 47

48. 48 Crane Use Optimization Optimization in construction is generally defined in terms of minimizing cost Many “second order” costs will be considered in a real world problem e.g. scheduling constraints. These are beyond the scope of this presentation We will consider the fixed cost of crane mobilization and the variable cost of crew hours required for the job

49. 49 Crane Use Optimization

50. 50 Crane Use Optimization In a simple optimization problem, the fixed and variable costs are functions of the crane type All cranes considered must first be found capable of completing all required lifts for the erection project A crane with higher fixed costs must be able to demonstrate lower variable costs than a competing crane to be a viable option The better of two competing cranes will then be determined by the size of the job – higher fixed costs will be offset by relatively lower variable costs on large jobs

51. 51 Steel Erection / Crane Cost Evaluation The crane-dependent cost of steel erection is

52. 52 Case Study Consider two options for erecting the Four Story Office Building –A large crawler lattice crane positioned in one location –A medium crawler lattice crane placed at two positions –A smaller rough terrain crane that must be repositioned several times

53. 53

54. 54 Steel Hoisting Cost Illustrator Mobilize Crane Position Crane Place Members Demobilize Crane Unload Trucks

55. 55 Jobsite Methods/Management Safety Rigging Crew coordination Crane foundation issues

56. 56 Safety OSHA requirements for steel erection are covered in Subpart R of Safety and Health Regulations for Construction Two sections are critical for planning crane operations –1926.752 Site layout, site-specific erection plans and construction sequence OSHA Steel Erection eTool Site Preparation.htm OSHA Steel Erection eTool Site Preparation.htm –1926.753 Hoisting and rigging OSHA Steel Erection eTool Cranes.htm OSHA Steel Erection eTool Cranes.htm

57. 57 Accidents Crane failures can be classified as structural or tipping Tipping can be caused by overload, inadequate foundation, or wind loading Structural failure may be due to overload or lateral load Operator error can cause either failure mode Operations near power lines present additional safety hazards

58. 58 Rigging Columns Beams Multiple Lift Rigging “Statics” of rigging

59. 59 Column Rigging This column is rigged using a device that allows the iron workers to release the rigging from the ground by pulling on the rope

60. 60 Beam Rigging Beams are usually lifted using a choker wrapped around the beam at the center of gravity Beams may also be hoisted with two cables

61. 61 Multiple Lift Rigging Multiple Lift Rigging is used to increase productivity and reduce crane operator fatigue OSHA Subpart R has specific requirements when using this approach

62. 62 Statics of Rigging Lifting a beam or column using a single cable is simply a problem of selecting a cable that can support the weight and attaching it at the center Some situations will require the rigger to calculate –Center of gravity –Load in skewed cables –Variable sling lengths –Spreader bar design

63. 63 Statics of Rigging 20 ft. @ 50 lb/ft 500 lb weight

64. 64 Crew Coordination Typical erection crew –Crane operator –Oiler (not required on hydraulic cranes) –Foreman –Four ironworkers – 2 ground, 2 connectors Order of assembly is determined in advance Crane operator may be guided by hand signals or two-way radios when visibility is inadequate

65. 65 Crane Foundation Issues Outrigger loads must be distributed over an area large enough to avoid overloading the soil Crane outriggers and tracks should be sufficiently offset from the base of slopes, excavations and retaining/basement walls Damage to underground utilities and structures from crane loads must be avoided Site soil conditions must be thoroughly evaluated before using a crane

66. 66 Soil Bearing Load Calculator Crane and soil properties were found in Ref. [4]

67. 67 Slopes, Excavations and Walls Loads from outriggers and tracks can cause shear failure near a slope Backfilled soil can be expected to have much lower bearing capacity Walls can be damaged by surcharge loads from cranes transmitted through the soil Cranes should be offset 1.5 feet* from the toe for every foot of excavation depth * Can vary due to soil type and moisture content

68. 68 Slopes and Excavations 1 1 1 1.5 Preferred In good soil Outrigger Load

69. 69 Option for Walls 1 1.5 Preferred

70. 70 Summary Proper crane selection and application is essential for a safe and economically competitive steel erection plan The crane must be placed on stable foundations and have adequate range and lift capacity to make the required placements

71. 71 References [1] AISC (2005) Jobsite Layout, Mobilization, Equipment and Coordination, American Institute of Steel Construction, Inc.. Chicago, IL. [2] AISC (2003) Structural Steel Construction Process - Technical, American Institute of Steel Construction, Inc.. Chicago, IL. [3] AISC (1999) Construction Management of Steel Construction, American Institute of Steel Construction, Inc., Chicago, IL. [4] Shapiro, H.I., J.P. Shapiro and L.K. Shapiro (2000) Cranes and Derricks, McGraw Hill Companies, Inc., New York.