Two education sessions at the May General Assembly meeting of the Association of Crane & Rigging Professionals (ACRP) in Kansas City, Mo., focused on the importance of understanding ground conditions for safe crane set up. The presentations by Ron Kohner, P.E., President of Landmark Engineering Services, and Michael Walsh, President of Dearborn Companies, were a reflection of current industry standards and the regulatory environment.
OSHA and ASME standards continue to place importance on ground conditions and proper setup for safe operation. In OSHA’s Compliance Directive for Cranes and Derricks in Construction, issued in October 2014, Item No. 1 on the agency’s site inspection checklist is to determine the adequacy of ground conditions beneath the equipment set-up area such as the support/foundation, matting, cribbing, blocking, etc. This sets the context for just how important an issue this is for crane operations.
Likewise, proper setup using outrigger pads or crane mats is addressed in ASME B30.5-2011. The standard also has placed increased responsibility on crane owners and lift directors for crane set up, holding these individuals accountable for site planning and prep.
Mr. Walsh explained that the newest OSHA 1926.1402 addresses the controlling entity’s repsonsiblity for ensuring ground conditions are adequate. While there has been a shift away from the crane company and crane operator having sole responsibility for this, they are still ultimately responsible for safe crane operation.
During his presentation, Mr. Kohner discussed that the allowable bearing capacity of the soil is the limiting factor in crane set up. Determining how much crane mat width is necessary to effectively distribute the load to the soil depends on what is underneath the mat.
But how do you know what the soil’s bearing capacity is? Walsh identified some red flags—crane placement near excavated areas, changing weather conditions, such as rain, underground utility structures or tunnels, and surcharges on utilities. Ultimately, however, it takes ground condition surveys using observational tools, geophysical tools, and samples of subsurface data to really know what you are dealing with.
Both Kohner and Walsh also identified the role crane mats and outrigger pads play in dealing with inadequate ground conditions.
To meet this need, DICA introduced FiberMax® crane pads in 2014. They distribute concentrated loads over large areas in order to safely reduce ground-bearing pressure. Made of fiber reinforced polymers, FiberMax crane mats are strong and rigid like steel and weigh up to 60% less than steel mats. FiberMax crane mats have crush ratings up to 1,000 psi and rated capacities up to 900,000 lbs.
In comparison to wood or steel crane mats, FiberMax crane mats provide better strength, durability and transportation cost savings. Unlike wood crane mats, FiberMax crane mats are also impervious to water absorption and rot. Once exposed to environmental factors and load stress, wood will splinter, crack and break over time. Internal welds on steel crane mats are susceptible to corrosion and fatigue and are not easily inspectable. In addition, steel can bend and suffer permanent deformation.
As Mr. Walsh noted in his presentation there are many options for dealing with inadequate ground conditions, including grading the soil, using geofabrics, and compacting the soil, but better distribution of the ground pressures through the use of crane mats will always be part of the equation.
DICA, Guthrie Center, Iowa, has been specializing in building a better outrigger pad since 1988. By creating engineered solutions for improving equipment stability and ergonomic safety, DICA has led the way in product innovation that outperforms wood and steel alternatives.
DICA outrigger pads, crane pads, and crane mats are used in a wide number of markets around the world, including construction, electrical utility, oil and gas and tree care as well as local, state and federal government agencies.