Important Terms For Your Safety

Specific to outrigger pads, crane pads, and foundational support.

Allowable Ground Bearing Pressure: The maximum permissible pressure, typically expressed in pounds per square foot (psf) or Pascals (Pa), that may be imposed on the supporting surface.This value may be equal to the Soil Bearing Capacity divided by a suitable safety factor or it may be a lesser value as limited by other considerations, such as the strength of the subsurface pipes. See Ground Bearing Pressure; see Soil Bearing Capacity.

A/D Director: (Assembly/Disassembly director) means an individual who meets this subpart’s requirements for an A/D director, irrespective of the person’s formal job title or whether the person is non-management or management personnel. (Source: A Glossary of Common Crane and Rigging Terms. Specialized Carriers & Rigging Foundation)

Assembly/Disassembly: Means the assembly and/or disassembly of equipment covered under this standard. With regard to tower cranes, “erecting and climbing” replaces the term “assembly” and “dismantling” replaces the term “disassembly”. Regardless of whether the crane is initially erected to its full height or is climbed in stages, the process of increasing the height of the crane is an erection process. (Source: A Glossary of Common Crane and Rigging Terms. Specialized Carriers & Rigging Foundation)

Average Ground Bearing Pressure (AGBP): Force/Area = AGBP. The average pressure exerted onto the ground under a specified area.

Bending Stress: Stress created in a load supporting member due to a bending action of that member, as oppossed to tensile or compressive action. (Source: A Glossary of Common Crane and Rigging Terms. Specialized Carriers & Rigging Foundation)

Blocking: Material used to support equipment or a component and distribute loads to the ground. It is typically used to support lattice boom sections during assembly/disassembly and under outrigger and stabilizer floats. Also called dunnage, cribbing, pads, and mats.

Bumper Outrigger: A hydraulic cylinder or manual jack located on the front bumper of a truck crane carrier to provide additional stability and extend the crane’s working range over the front of the carrier Also: Fifth Outrigger. (Source: A Glossary of Common Crane and Rigging Terms. Specialized Carriers & Rigging Foundation)

Composite: A composite material (also called a composition material or shortened to composite, which is the common name) is made from two or more constituent materials with significantly different physical or chemical properties that, when combined, produce a material with characteristics different from the individual components. The individual components remain separate and distinct within the finished structure, differentiating composites from mixtures and solid solutions. DICA’s proprietary engineered material for SafetyTech Outrigger Pads & RoadWarrior RV Jack Pads are not a composite. All FiberMax Crane Pads and Outrigger Pads are composites.

Crane Mat: An assembly of structural members arranged to distribute the loads from a crane’s tires, outriggers, or crawler tracks over a large area in order to reduce the ground bearing pressure and minimize settlement.

Crane Pad: An area of compacted or otherwise specially prepared soil, concrete, mats, steel plate or other materials designed to support a mobile crane. See DICA’s crane pads.

Cribbing: Blocking materials that are used to increase the bearing area and height. See DICA’s plastic cribbing blocks.

Critical Lift: A crane lifting operation judged to involve an exceptional level of risk, due to factors such as load weight, lifting height, procedural complications, or proximity to situational hazards. Critical lifts may be identified by conditions exceeding a specified percentage of the crane’s rated capacity; however many more complex issues may be involved. (Source: A Glossary of Common Crane and Rigging Terms. Specialized Carriers & Rigging Foundation)

Crush Rating: The allowable amount of pressure that an outrigger pad, crane outrigger pad, cribbing or crane pad is rated to carry, based on the strength of the material.

Deflection: The bending of supporting materials as downforce is applied. See Downforce.

Derrick: A lifting device consisting of a vertical mast secured at the top by guy lines or braces and utilizing hoist machinery and operating ropes. A derrick may or may not utilize a boom. (Source: A Glossary of Common Crane and Rigging Terms. Specialized Carriers & Rigging Foundation)

Derricking: Operation of changing boom angle by varying the length of the boom suspension ropes. (Source: A Glossary of Common Crane and Rigging Terms. Specialized Carriers & Rigging Foundation)

Displacement: The difference between the unloaded horizontal positions of the outrigger pad, compared with the fully loaded horizontal position of the outrigger pad.

Downforce: The force that is generated in a downward direction from the outriggers through the outrigger float and onto the outrigger pads.

Dunnage:Loose materials used to support, separate and protect equipment, parts, and accessories during storage and stabilization. 

Effective Bearing Area: The area in full contact that is effective in distributing the applied load to the underlying surface.

Flex Modulus (Bending Stiffness): The ratio of stress to strain that determines the tendency of a material to bend.

Float: The rigid pan-like structural component that attaches to the outer end of a mobile crane’s outrigger to provide some load spreading of the outrigger load to the supporting surface. The floats are provided by the crane manufacturer. Also commonly called outrigger float, outrigger pad, outrigger pan, foot, or pad.

Ground Bearing Pressure (GBP): The pressure, typically expressed in pounds per square foot (psf) or Pascals (Pa), that a crane imposed on the supporting surface.  See Allowable Ground Bearing Pressure.

Ground Bearing Capacity (GBC): The strength of the ground, or its ability to support a pressure.

Ground Conditions: The ability of the ground to support the equipment (including slope, compaction, and firmness) (29 CFR 1926.1402)

Grounding Mat: Grounding device used when a crane will be working in a relatively fixed location which is near electrial hazards. Equipment is placed on that mat and bonded to it. The grounding mat area is usually enclosed with a fence to prevent personnel from stepping on and off the mat during operation of the machine. (Source: A Glossary of Common Crane and Rigging Terms. Specialized Carriers & Rigging Foundation)

Grounding Rod: Grounding device used when a crane will be working in a relatively fixed location which is near electrial hazards. The ground lead is connected to the rod and to the machine, with the rod placed as close to the machine as possible. (Source: A Glossary of Common Crane and Rigging Terms. Specialized Carriers & Rigging Foundation)

Jack: A mechanical or hydraulic device for lifting heavy weights short distances. RELATED: Outrigger Jack.(Source: A Glossary of Common Crane and Rigging Terms. Specialized Carriers & Rigging Foundation)

Lift Director: Directly oversees the work being performed by a crane and the associated rigging crew. (Source: A Glossary of Common Crane and Rigging Terms. Specialized Carriers & Rigging Foundation)

Lifting Capacity: The maximum gross load weight that a crane manufacturer has determined a crane can safely handle under specified conditions of counterweight, level, outrigger position, boom length, radius, etc. Lifting capacities are published in tables known as capacity charts. The lifting capacity is NOT the maximum load that a crane can lift before it beings tipping or collapses. (Source: A Glossary of Common Crane and Rigging Terms. Specialized Carriers & Rigging Foundation)

Mat: Individual timbers fastended together into units, steel plates, or woven wires placed under crawler tracks, wheels, or outrigger pads to prevent sinking by increasing the bearing area contacting the ground thereby reducing bearing pressures. (Source: A Glossary of Common Crane and Rigging Terms. Specialized Carriers & Rigging Foundation)

Maximum Load: The heaviest load that a crane’s capacity chart shows it is capable of lifting in a given configuration. (Source: A Glossary of Common Crane and Rigging Terms. Specialized Carriers & Rigging Foundation)

Maximum Load Radius Limit: The longest distance from the crane’s centerline of rotation (radius) at which a crane with a given boom length can lift any load. (Source: A Glossary of Common Crane and Rigging Terms. Specialized Carriers & Rigging Foundation)

Maximum Outrigger Reaction Force: The maximum amount of weight that the equipment can exert through its outriggers.

Maximum Radius: The longest distance from the crane’s centerline of rotation (radius) where a maximum load can be lifted within the crane’s rated capacity. (Source: A Glossary of Common Crane and Rigging Terms. Specialized Carriers & Rigging Foundation) See Maximum outrigger load.

Minimum Radius: The shortest distance from the crane’s centerline of rotation (radius) at which a crane with a given boom length can lift any load. (Source: A Glossary of Common Crane and Rigging Terms. Specialized Carriers & Rigging Foundation)

On Outriggers: (1) The condition where a crane operates with all outriggers fully extended and set to level the crane body with its tires or crawlers free of the ground. (2) Rated capacities for a crane which are applicable when the crane is operating with all outriggers fully extended and set to level the crane body with its tires or crawlers free of the ground. Related: On Rubber. (Source: A Glossary of Common Crane and Rigging Terms. Specialized Carriers & Rigging Foundation)

On Rubber: (1) The condition where a crane operates with any of its tires in contact with the ground. (2) Rated capacities for a crane which are applicable when the crane is operating with any of its tires in contact with the ground. Also: On tires. Related: On Outriggers. (Source: A Glossary of Common Crane and Rigging Terms. Specialized Carriers & Rigging Foundation)

Outrigger: A beam which extends from the lower works of a crane to increase the crane’s stability. The beams may be either extendible/retractible or fixed length and typically utilize some type of pad to distribute loads to the ground surface. (Source: A Glossary of Common Crane and Rigging Terms. Specialized Carriers & Rigging Foundation)

Outrigger Beam: The part of an outrigger system which extends horizontally from  the outrigger box to support the vertical outrigger jack. (Source: A Glossary of Common Crane and Rigging Terms. Specialized Carriers & Rigging Foundation)

Outrigger Jack: The hydraulic cylinder on the outrigger beam which extends vertically to raise and lower the crane. (Source: A Glossary of Common Crane and Rigging Terms. Specialized Carriers & Rigging Foundation)

Outrigger Pad/Float/Foot: The metal pan structure supplied by the equipment manufacturer that distributes the total load from the outrigger to the underlying blocking and ground surface. Typical shapes are round, square, rectangular or octagonal. SEE: Float.

Outrigger Pad: A wood, metal, or synthetic structural element that is placed on the supporting surface and on which bears the crane’s float that is used to distribute the outrigger load over a larger area. See DICA’s outrigger pads.

Outrigger Pin System: A hydraulic system available to facilitate outrigger box removal by means of hydraulic cylinders used in place of the standard outrigger box mounting pins. (Source: A Glossary of Common Crane and Rigging Terms. Specialized Carriers & Rigging Foundation)

Pad: Compacted soil , concrete, wooden timbers or mats, or steel plates assembled into a system for supporting a crane with minimal settlement. (Source: A Glossary of Common Crane and Rigging Terms. Specialized Carriers & Rigging Foundation)

Pontoon: (1) A pan type structure which attaches to the bottom of vertical outrigger jack to distribute loads over the supporting surface. SEE: Float. (2.) Large steel pads usually fabricated to support crane tire or outrigger loads on soft soil. Pontoons are the steel equivalent of wooden crane mats. (Source: A Glossary of Common Crane and Rigging Terms. Specialized Carriers & Rigging Foundation)

Proof Test: A nondestructive test which applies a proof load to a sytem or component. (Source: A Glossary of Common Crane and Rigging Terms. Specialized Carriers & Rigging Foundation)

Rated Capacity: The maximum working load on a crane or rigging component permitted by the manufacturer under specified working conditions. ALSO: Working Load Limit. (Source: A Glossary of Common Crane and Rigging Terms. Specialized Carriers & Rigging Foundation)

Screw Jack: Threaded vertical support cylinder typically used on outrigger or ring-type attachments to provide leveling adjustment. RELATED: Jack.

Screw Jack Pad: Pan type structure attached to the bottom of a screw jack to distribute loads to the ground, similar to an outrigger pad. (Source: A Glossary of Common Crane and Rigging Terms. Specialized Carriers & Rigging Foundation)

Site Supervisor: Exercises supervisory control over the worksite on which a crane is being used and over the work that is being performed on that site. (Source: A Glossary of Common Crane and Rigging Terms. Specialized Carriers & Rigging Foundation)

Stablizer: An extendable or fixed members(s) attached to the mounting base to increase the stability of the crane, but which may not have the capability of relieving all of the weight from wheels of tracks. (Source: ASME B30.5 &B30.22)

Supporting Materials:  OSHA 1926.1402(a)(2) “Supporting materials” means blocking, mats, cribbing, marsh buggies (in marshes/wetlands), or similar supporting materials or devices.

Yield: The point at which material begins to deform, bend or break. Once yield occurs, materials will not return to their original shape and material properties are permanently altered.

Outrigger Pads