There are two types of software that can help rigging. The first kind is a sort of mathematics aid that helps calculate the forces likely to be acting on slings and beams, and then spitting out the spec likely to be needed for the job.
German chain and rigging gear supplier Rued has published a CD-ROM that contains a catalogue of its range of lifting and lashing equipment. This also includes some software that walks riggers through the design of a rigging system. Users start by entering the load weight, and the type of rigging: one, two, three or four-leg slings, or baskets. Then there are a few standard questions, including whether there is a possibility of shock loading, sharp edges, extreme temperatures, corrosive environments, or whether the rigging will choke together a bundle of material. The software returns not only the sling length, but also the optimum diameter of sling for the job, and a complete parts list. A couple more clicks and users can order it all.
Gunnebo Industries’ web site walks users through the steps to build a bespoke chain sling. Users choose one, two, three or four legs, the working load limit, a choice of top link, the chain length, angle and end fittings. It also generates a report that customers can use to place an order.
The third calculation-based CD-ROM, RigRight 1.0 software from rigging expert Harry Donovan’s California-based theatre rigging company Rigging Books and Software, is brand-independent. It promises to calculate loads and geometry for common types of stage rigging assemblies. Although the software seems mainly for hanging things from fixed points, it still promises to compute forces on rigging. In particular, it computes dimensions, lengths and forces for two-leg and three-leg bridles and gives positions, lengths and forces for breastlines and deadhangs.
The other type of rigging planning software is part of computer-aided design software that sets a computer-generated crane inside a virtual world. Rigging, of course, can play a prominent role in the large and complicated lifts that necessitate 3D planning in the first place. In these systems, the rigging equipment is stored in a virtual object library. This approach does require crane companies to record accurately their rigging gear, down to each shackle, in a database. The final result usually looks great, and the software can spit out a parts list. On the down side, these systems have no safeguards to make sure that the selected rigging arrangement can safely lift a load in real life.
The three-dimensional load planning software Cranimation V3 from Cranimax, sold with Terex cranes, starts users from the crane hook and walks them down the load path. Users first choose a hook block, then the length and number of falls of rope, or chain, from the hook block to spreader. There is a library of spreader bars with pick-point notations. Users can choose the load slings, and the type of securement of the slings to the load; clamps, eyebolts or trunnions, for example. Cranimation will tell users the sling angles and the complete rigging weight, and generates a complete rigging parts list. The software assumes that load planners are knowledgeable enough not to choose a 300t hook block to lift a 500t load, for example.
Independent software LiftPlanner has a library of 850 rigging components, with weights. The rigging components have special interlink points that allow users to connect shackles to slings semi-automatically: ‘like snapping LEGO bricks together,’ says developer Jim Meehan. The software adds up the total weight of the rigging, and reports what items are needed. It also automatically de-rates slings depending on their angles. A separate module enables users to build lifting lugs to exact dimensions.
3D Lift Plan, sold with Link-Belt mobile cranes, is planning to launch a rigging database and planning module in late 2009, according to Tawnia Weiss, president of AIA Software. In the meantime, the system, which creates 3D load plans on the internet, allows some basic rigging equipment selection. Users can choose a spreader bar and single, two-leg or four-leg bridles. The programme calculates sling length, angles and rigging height. There is also a library of possible load objects. Sling capacity is not currently displayed.??
