Rigging is an essential process in almost any construction project, from the building of small houses to the erection of large skyscrapers. Essentially, the process of rigging involves the highly technical operations involved in lifting and moving large, heavy objects and materials from one point to another. Far from being a simple exercise in brute force, rigging requires a high level of knowledge and skill on the part of the rigging engineer to ensure the correct distribution and management of the forces involved, while also maintaining a high standard of safety in what can be a potentially dangerous operation for construction workers and the site itself. Riggers must go through an intensive process of training and apprenticeship before becoming qualified in order to learn the skills involved.
There are several different fundamental operations involved in rigging. Perhaps the most basic and widely used is that of lifting. In order to lift a heavy object off the ground, a number of different tools can be used. Most common among these is the jack. A toe jack is one of the simplest forms of this type of tool, and is used by inserting the toe (being a flat metal piece protruding from the bottom of the jack itself) underneath the object to be lifted. Mechanical or hydraulic force is then used to raise the toe. Other types of jacks used for lifting include bottle, inflatable, journal, and screw jacks.
Rather than lifting from the bottom, sometimes it can be preferable to hoist heavy objects from the top, particularly if they need to be raised to another level of construction. Chain hoisting is a common technique used in this process, and utilizes a pulley system to distribute force. For heavier loads, lever hoists can also be used to allow for more lifting power.
Other important processes involved in rigging are those of pushing and pulling heavy objects from place to place. Dollies are wheeled platforms that are often used for this task. Objects can be placed on top of the dolly’s load bed before being moved freely on wheels, rollers, or skates. Different types of dollies are suitable for different kinds of loads, and also vary depending on the required range of movement, so knowing how to select the right type of tool is an essential part of the rigging engineer’s job. Dollies (or other wheeled objects) can also be attached to moving machinery by means of chains, hooks, shackles, and couplings, and towed to a new location.
For large-scale projects, more heavy-duty equipment such as forklifts, twinlifts, cranes, and risers perform many of the tasks essential to the rigging process. Cranes in particular are well-used in a variety of construction projects, as they are capable of lifting weights of several tons to great heights.
Rigging can also involve installing anchors and harnesses to allow workmen to rappel down the side of a building, as well as the securing of structures such as cell phone towers and scaffolding by means of ropes, wire, or chains.