What’s the Science Behind Crane Rigging?
Rigging services play a critical role in the safe operation of cranes for lifting loads. Most objects lifted by crane rigging are fundamentally the same. Shape, weight, and rigging may vary, but the loads always live under the hook.
Getting rigging services right requires mathematics, geoengineering, and mechanical information. To ensure teams understand each project, riggers outline the requirements and plan for lifting using a crane and components.
Several interrelated, complex characteristics of a load project are measured and considered during crane rigging:
Load DetailsCrucial information for the rigging services plan includes the following characteristics of the load:
- load weight
- load dimensions (length, width, depth)
- center of gravity
- lift / sling points
- pickup radios
- location radius
- lift height
- total weight (load and all accessories)
- crane capability
The load details of the project plan will be matched against crane capacity information. A crane load chart is used to identify the appropriate machine for the project, based on several characteristics:
- length of jib
- outrigger spread and load
- ground bearing capacity
- counterweights required
- crane weight
- crane make/model
- Ground Condition
In addition to having the right equipment, crane rigging involves working with geo-technical engineers to ensure the ground can support the load and the crane. More specifically, the area must meet these criteria:
- the ground, if back-filled, was compacted to provide a solid surface
- the area has no voids or underground services that will weaken the surface
- adequate space is available to extend outrigger jacks and beams
- load rigger mats are available if hydraulic mobile cranes are used
- access roads and final load location can accommodate the load weight
- any large trees or buildings are noted along the project route
With project, equipment, and location specifications outlined, rigging services teams can create a rigging plan. The objective of the plan is to illustrate all connection points, forces applied and how the project will be slung together. The rigging plan is a detailed drawing showing the configuration of all load lifting points. It also provides information about the slings, shackles, ropes, blocks, and beams used during the project. Details gathered earlier in the planning process are incorporated into the rigging plan including:
- Load center of gravity
- Lifting gears or slings recommended
- Lifting capacity
Wind, temperature, and visibility can have an adverse effect on crane lifts and are considered during planning.
- For example, wind gusts of more than 15 miles per hour can cause postponement or cancellation.
- Temperatures below 10 F can impair crane hydraulics.
- Rain, fog or snow can negatively affect the visibility of the boom tip, operator, or the load.
Communication and Training Plan
Putting a communication and training plan in place for the site can improve project safety. This plan includes direction for:
- a system of signals the team knows how to use
- individual roles training
- a process for communicating across roles
- how signalers will be identified
- warning systems for keeping lift areas clear of non-essential personnel
The science behind crane rigging establishes good practices and correct lifting methods, showing how loadings can change significantly with only a few modifications. When large objects are moved efficiently and safely with minimal manual handling, major accidents can be avoided.
But planning and good communication are also key elements of good rigging services. Successfully controlling lift operations and using lift equipment safely takes management commitment, team competence, and appropriate resources.
The Number One Crane and Rigging Company in the Pacific Northwest
For more information about how NessCampbell Crane + Rigging can support your heavy machinery moving, rigging, erection, and assembly, contact our team. We understand the science behind crane rigging and will complete your project safely, on time, and cost effective.