Making Effective Crane Outrigger Pad Choices
Choosing the right outrigger pads helps ensure efficiency and improve safety on jobsites. The stability they provide for cranes ensures a safer work environment for operators and crews.
However, not all pads serve the same purpose, and there are several factors to consider when making effective choices. Additionally, there are best practices to employ for maintaining pads to ensure safety and long service life.
Suppliers of crane outrigger pads are a key source of important and valuable information for operators. Recently, Eric Steiner, marketing director, Bigfoot Construction Equipment, and Kris Koberg, CEO of DICA, provided expert input on outrigger pad specification considerations and ways to properly maintain the equipment:
What do crane owners need to consider when specifying outrigger pads?
Steiner: Identifying the exact ground bearing capacity (GBC) of the jobsite based on the soil type is crucial. This will not always be easy to find, however certain soil types have established ground bearing capacities which can be used as a guideline to properly broadcast the weight.
Koberg: For the crane owner to determine the required bearing area, two key factors must be defined, including the outrigger reaction force and the allowable ground bearing pressure. Once these values are established, the minimum required bearing area can be calculated by dividing the outrigger reaction force by the allowable ground bearing pressure. The minimum bearing area to meet the allowable ground bearing pressure objectives is the result of the calculation.
What role does outrigger pad material selection play when making equipment choices?
Koberg: When selecting the appropriate supporting materials, it’s important that they meet several key requirements. First, they must be strong enough to prevent physical failure under load. Second, they must possess sufficient stiffness to effectively distribute the load and create an effective bearing area that meets the minimum requirements. Lastly, they must be stiff enough to minimize deflection to acceptable levels.
Steiner: Each material has its pros and cons. Wood pads are more rigid, so they will not deflect, but can break if overloaded. Composite pads have a natural acceptable deflection, which is what prevents them from cracking or breaking. Maintenance and replacement is a key consideration for pads as composite pads have a lifetime guarantee while wood pads do not.
Geography is the main factor, as different climates present different challenges for certain materials. For example, wood pads can last up to 10 years under typical use, but if the outrigger pad is being used in a dry climate that does not see a lot of rain it can last much longer. If the equipment will be operating in climates that can be rainy one day and then humid and muddy the next, or in snowy/icy climates, then a composite pad would be better suited for the job, which allows for fewer replacements.
There are instances when both materials can be utilized. If the ground conditions are exceptionally poor, using a combination of wood and composite pads is the safest set up because a wood pad will spread the load more effectively to the composite pad, preventing deflection and giving a wider footprint for the outrigger float.
What practices should be employed for maintaining pads to ensure safety and long service life?
Koberg: Materials should be inspected before each use, and any that no longer meet the necessary structural integrity to support equipment loads and pressures should be replaced. It’s important to use the materials only for their intended purpose, as overloading, misuse or abuse can negatively impact safety and significantly reduce their lifespan.
For wood products, including timbers, mats, or pads, life expectancy is influenced by the species of wood and its exposure to water, humidity, UV and insects. Since wood is prone to rot, especially during storage, care should be taken to separate all wood products with cribbing and avoid stacking them directly on top of one another.
Specific inspection criteria vary based on the material type. When using metal, look for bent structural components, punctures or ruptures, signs of crushing, weld damage, cracks and any evidence of corrosion, rust or pitting. Wood should be checked for cracks, checking, shakes, splits, high moisture content, chemical damage, rot, and bent, broken or missing through-bolts. Synthetics need to be inspected for cracks, fractures, permanent deformation or signs of crushing.
Steiner: Best practices to ensure long service life of pads include proper storage, correct pad sizing, proper handles and informed setup. Proper storage is especially important for wood pads. Leaving them outside makes the pads vulnerable to rain and the elements, potentially impacting their effectiveness and creating a shorter lifespan. Regardless of material, pads need to be monitored proactively, making sure there are no cracks, breaks or excessive deflection/bending every time a pad is used.
Range of Products
DICA EcoMax crane pads combine alternating solid composite timbers and steel I-beams connected with through-bolts for maximum load distribution. The I-beam flanges create a connection with the composite timbers. This, and the strategic placement of the through-bolts ensures maximum load distribution and minimizes ground bearing pressures.
EcoMax crane pads were developed as a lower cost option to steel and the company’s FiberMax crane pads. They are designed for use with mobile and self-erecting tower cranes. The pads are available in sizes ranging from 20 to 40 square feet with maximum rated capacities of 175,000 pounds to 325,000 pounds, respectively.
DICA FiberMax crane pads provide similar strength and stiffness characteristics as steel crane mats but weigh up to 60% less for lower transportation costs and faster setup and tear down times. The pads, designed to support and stabilize mobile cranes up to 500 tons, have crush ratings up to 1,000 PSI and 400,000-pound rated capacities.
Made from Fiber Reinforced Polymer (FRP), FiberMax composite crane pads are not affected by fluids, chemicals or UV, and will not rust, rot or degrade in extreme hot, cold or maritime environments.
DICA EcoMax and FiberMax crane pads are nonabsorbent, easy to clean and eliminate site to site contamination.
New from DICA for cranes and boom trucks is the company’s LevelRight solution that allows users to adjust the overall angle from 0-10 degrees and in two planes up to 5 degrees. The 24-inch diameter LevelRight will accept up to a 20-inch square or 24-inch round outrigger float and has a rated capacity of 350,000 pounds.
LevelRight is made of SafetyTech material with DICA SafetyTexturing on the top and bottom surfaces. It also has a built-in bubble level to provide operators with confirmation when they have a level surface under their equipment’s outriggers. In situations where cribbing blocks are needed for extra height, LevelRight can be used as the base under DICA ProStack cribbing blocks to ensure the blocking is on a level surface.
Bigfoot Construction Equipment offers both custom composite and water sealed wood outrigger pads in a variety of sizes and colors as well as steel crane mats, known as American Armor. Bigfoot’s outrigger pads range up to 60- by 60-inch pads rated to 200 tons for cranes, with thicknesses depending on the application ranging from one to four inches. In order to address heavier equipment up to 500 tons, Bigfoot offers American Armor steel crane mats.
Custom composite outrigger pads from Bigfoot come in both stock and custom sizes and can be modified to include an A-frame bevel around the edges that prevent 45-degree outriggers from sliding off the pad. Bigfoot also offers a slide pad option, allowing the outriggers to go up and down with the outrigger pads attached, commonly used for spyder cranes.
Bigfoot’s customizable pad options include a range of handles such as standard nylon rope and internal pad handles, safety chain handles for heavy-duty pad sizes that are rated at 3,100 pounds, wire rope/steel choker handles for larger pads being used in extreme conditions such as mud, ice or snow and stainless steel metal handles.
Industry Guide
SC&RA, the Specialized Carrier & Rigging Association, has unveiled a new resource — A Guide to Outrigger Pad Materials, Selection and Usage. The guide provides information and best practices on the types and selection of supporting materials, such as pads, dunnage, etc., to minimize the outrigger bearing loads imposed on supporting surfaces during load handling activities.
The resource promotes awareness of existing standards and regulations, lift planning preparation, supporting materials and types and jobsite requirements. Controlling entities, lift directors, site supervisors or others who have responsibilities by standards or regulations for lift planning will find this guide helpful.
The document was developed by members of the Outrigger Task Force, including Christian Coronel Armijos, Bragg Companies; Pat Clark, Patrick Clark Consulting; Dan Durrett, Maxim Crane Works, L.P.; Tyler Elliff, Precision Crane Service; Kris Koberg, DICA; Jeremy Landry, Deep South Crane and Rigging, LLC; Kevin O’Neill, Bay Crane Service; Jonathan Parnell, ITI – Industrial Training International; Ingo Schiller, Path Finder Consulting Group LLC; Bill Smith, NBIS; Jeff Steiner, Bigfoot Construction Equipment; Mark Wade, Capital City Group, Inc.; and Michael Walsh, Dearborn Companies.
