U.S. regulatory bodies and site owners continue to place emphasis on understanding ground conditions and using outrigger pads or crane mats to provide the necessary foundation support. This includes proper matting, cribbing and blocking.While it’s possible to determine pressures to be exerted by the crane onto the ground, for many lifts with smaller cranes, operators and crane crew members may not have that information readily available and are often left with determining the sufficiency of the ground and the current ground conditions. The most common way to solve the dilemma – and to help prevent catastrophic ground failure – is to use outrigger pads or crane pads. Accurately sized and appropriately engineered outrigger pads will increase the area of contact the crane has with the ground, thereby reducing the ground bearing pressure.
But what do you do if the ground is not level under all outriggers and you don’t have the time, equipment or materials to properly prepare the area? What if your work takes you to roadsides and ditches where the terrain is intentionally sloped? Typically, an operator’s only job site options are stacking timbers or some sort of wood that can be found on site to provide height under the equipment’s outriggers.
Wood is inexpensive and convenient, but its porous and fibrous structure has disadvantages that include unknown strength and rigidity properties. Using cribbing that is not engineered for crane outrigger use can result in cracking, breaking and splintering when exposed to outrigger pressure.
ProStack, a new cribbing product from DICA, provides an engineered solution to these challenges.
“Introduced at ConExpo 2017, attendees seeing ProStack for the first time repeatedly said they had never seen anything like this before,” said Kris Koberg, CEO. “ProStack is designed to provide height for operators in environments where there are significant changes in grade. It is designed to be used under boom trucks, digger derricks and aerial bucket trucks, or any equipment with outrigger loads that do not exceed 110,000 pounds,” he said.
DICA’s ProStack Cribbing Kit is composed of three basic parts: a base outrigger pad, interlocking cribbing blocks and a high friction top grip pad. The base ProStack Outrigger Pad is manufactured with a pyramid-shaped surface that interlocks with the cribbing blocks. On top of the base pad, operators stack layers of 6 by 12 by 24-inch cribbing blocks with the pyramid-shape surface, that lock into the base pad. Lastly, a ProStack Grip Pad is placed on top of the stack to protect the pyramid surface on the cribbing blocks and provide a high friction surface for the outrigger foot. To aid in the set-up, ProStack wedges are available to fill the gap between the ground and the outrigger pad when the conditions call for it.
As a leader in engineered ground support products since 1988, DICA continues to apply new technologies to outrigger pad and crane pad applications.
ProStack Cribbing boasts benefits that are hallmarks of DICA products, Koberg said. The product was designed to be strong and ergonomic, impervious to environmental conditions, manufactured from quality engineered materials and specifically suited to the job.Among the first customers to put ProStack Cribbing to use is a major utility company.
“The main benefit is the ability to provide cribbing to our crews that meets OSHA requirements for a stable setup,” said the transmission and substation safety coordinator.
He explained that wood cribbing breaks down over time, and to be stable, layers of wood need to be bolted together.
“But people rarely take the time to do that,” he said. “With ProStack, the interlocking design is stable, we are working with a known rating and working load limit, and it works with our existing outrigger pads so that we don’t have to carry another set of outrigger pads.”