Ground stabilization is key for safe operations
By D.Ann Shiffler07 March 2018
Beyond an experienced crane operator, the most important element of safe crane operation is proper ground stabilization. Few people will argue with this statement.
For this reason, there are many different types of ground stabilization products, all that meet specific needs, depending on the ground conditions, the crane being used and other variables.
Brewer Crane and Rigging of Lakeside, CA reports it can move DICA’s FiberMax crane pads up to 75 percent faster than heavier wood mats or steel plates.
Crane mats, pads and cribbing are also made from a variety of materials including wood, composite wood, composite plastic, composite fiberglass and metal. While there is no question that some mats and pads are stronger and longer lasting than others, most crane-owning companies have a variety of different types of mats, pads and cribbing as a part of their rigging inventories.
Among the biggest differences between crane mats and pads is price. The more engineered the product the higher the cost. However, the higher cost composite products may also be more cost effective in the long run because of their life cycle and ease of use.
American Cranes & Transport invited crane mat, pad and cribbing suppliers to submit information about the products they sell.
For 27 years, Robert Lifton has owned Lifton’s Inc., which produces outrigger pads and mats that are made from multi-layer birch plywood.
“Unlike the soft fir 4-layer lumber yard plywood, Lifton uses a high-grade birch plywood that has 13 layers per three-quarters of an inch,” said Lifton. “This creates a very strong pad able to support 40 to over 100 tons depending on thickness. The pads and mats have a long history of safety in the field.”
Lifton said his company’s typical 2 ¾-inch pad has 52 layers.
“The strength-to-cost ratio is excellent,” he said. “The plywood product has a surface that is not inclined to slide. Because they do not tend to bowl in the center, they are highly predictable and do not lose their shape. The larger pads have a strong bevel on the edges to extend the life of the plywood.”
Each Lifton pad has lag screws coming from the top and bottom, cross locking the plywood. With rope handles, (or on the large pads chain handles), attached through the pad with large eye bolts, the handles are secure, he said.
Each Lifton pad has lag screws coming from the top and bottom, cross locking the plywood. Rope or chain handles are secured through the pad with large eye bolts.
“Many customers prefer the thicker pads or mats for ease in setting up and leveling equipment,” Lifton said.
Lifton’s pads are available from 2-inches thick to more than 8-inches thick on the super mats. The super large mats are generally picked up and placed by the crane or a forklift. There are over 50 combinations of thicknesses and sizes available in Lifton’s mats.
“Because of the lower cost of the pads, they are excellent for the crane rental business,” Lifton said.
Founded by Dick and Carolyn Koberg, DICA has been producing crane mats for 30 years. In the early years the company produced outrigger pads made out of wood. But Dick Koberg realized there was a better way to assure ease of use, lighter weights, ergonomic safety and lifespan. He developed an engineered outrigger pad that would ensure proper load distribution on a range of ground conditions and provide “unbreakable strength.”
DICA is still a family business with the Koberg siblings now at the forefront of the management team. Kris Koberg is CEO of the company that produces three types of outrigger pads and cribbing, including the SafetyTech outrigger pads, FiberMax crane pads and ProStack Cribbing.
DICA’s SafetyTech outrigger pads are an engineered thermoplastic outrigger pad equipped with a patented TuffGrip handle that makes the pad easy to move around. SafetyTech pads are available in 30-plus square, round and specialty shapes and they are typically used by aerial bucket trucks, digger derricks, concrete pumpers and mobile cranes with a lifting capacity up to 100 tons. These pads can be cleated for additional ground traction and they are available in several specialty formats.
DICA’s FiberMax crane pads are manufactured with fiber-reinforced polymers (FRP). FRP is a composite material made of a vinylester polymer that is reinforced with specially designed fiberglass. The FiberMax design leverages the benefits of a strong, stiff and lightweight material and a sandwich construction with internal bi-directional shear webs. The pad distributes the load similar to steel constructed pads while minimizing operational costs, according to DICA. An external steel frame protects the mat and provides attachments points for customer-designated lifting hardware.
FiberMax crane pads have similar strength properties as steel crane pads but weigh up to 60 percent less. They are designed to distribute loads up to 375,000 pounds, which typically means mobile cranes ranging from 100 to 600 tons of lifting capacity. DICA said the FiberMax pads are longer lasting than wood or steel crane pads and will not rot or rust.
DICA also offers its ProStack cribbing, which is a combination of engineered thermoplastic blocks, a base SafetyTech Outrigger Pad and a high friction top grip pad. The outrigger pad and block components are made with interlocking pyramids that allow the pad and blocks to lock together for higher safety and performance than non-interlocking cribbing. They also feature the TuffGrip handles and are designed to support loads up to 110,000 pounds. They are generally used on boom trucks, digger derricks, aerial devices and small to medium-sized mobile cranes, DICA said.
Strong and durable
Bigfoot is a multi-generation American family manufacturer of outrigger pads. The family started out as an end-user of large equipment, according to Jeff Steiner, president, Bigfoot Outrigger Pads. His father, known as “Bigfoot Bill,” started building wood outrigger pads while he was a concrete pump operator. One of his sons worked as a tree trimmer and a lineman working with 40-ton cranes.
“Nobody understands the end-user point of view or field conditions more than this American family manufacturer of outrigger pads,” said Steiner. “With the experience working with and building outrigger pads, Bigfoot has designed and tested materials with the best compressive load ratings.”
The Bigfoot Big Grip Pad was designed for field usage and can be placed face up or down so that the teeth bite into the surface area of contact.
Bigfoot uses a composite ultra-high molecular weight (UHMW) plastic for one line of outrigger pads, and it also produces wooden pads made of Baltic Birch and plywood that is laminated and bolted together.
For cranes, Bigfoot mats range in sizes and thickness for up to 120-ton capacity cranes.
Bigfoot’s composite outrigger pad material has comparable load ratings to high grade steel at one-seventh of the weight, Steiner said. This material will last a life time and hold up to extreme conditions and weather.
Bigfoot’s PSI value, compressive load and sheer strength has been formulated to achieve the highest level of safety in the field, Steiner said.
Other products include Bigfoot’s Stop Bar, which is built to make sure the outrigger stays on the outrigger pad. Bigfoot installs anywhere from one to four stop bars based on customer request.
Bigfoot’s Slide Pad was built to address customer demand for the smaller and more mobile equipment in the field. This outrigger pad has a removable stop bar that stays on the equipment after the stop bar is re-installed and allows the operators to set up several times at one job location without picking up and setting up each time.
Bigfoot’s new Boot Pad is built for larger equipment and is designed based on the customer’s outrigger size. The open nose style allows material that would build up to escape; it also allows the operator to see that the outrigger is properly deployed on the outrigger pad. The boot is made out of Bigfoot’s UHMW composite material.
The Bigfoot Big Grip Pad was designed for field usage. The pad is placed face down and the teeth bite into the surface area of contact, which works well in icy or muddy conditions. When the Big Grip Pad is used face up the teeth bite into the cribbing or dunnage or another Big Grip pad that is placed faced down to reach the height needed to level the crane or equipment.
Bigfoot uses a Baltic Birch for its wooden outrigger pads. This wood is lighter and stronger than American hardwoods and has found exceptional success in extreme field conditions, Steiner said. While wood will break down over time, it will give visual indictors that replacement is needed. Baltic Birch has a typical field use of 10 years, Steiner said.
Mabey Inc. is a leader in providing and installing temporary roadway and work pad matting systems. Mabey’s Dura-Base composite mats are a solution for soft or delicate grounds needing protection or stability. The Dura-Base mat features an interlocking system to form a temporary roadway allowing cranes to have access to challenging or remote worksites.
Dura-Base mats are made of 100 percent of high density polyethylene (HDPE) material, engineered and manufactured in the U.S. The mats are 8 by 14 feet and weigh 1,000 pounds per mat.
The quality control in manufacturing provides consistent strength properties capable of supporting up to 600 pounds per square inch, according to Mabey. They feature a locking pin system to securely fasten each mat to adjacent ones and to layer mats as needed depending on conditions. This system creates a temporary road or work pad that is secure, strong and stable, the company said.
Composite mats have numerous advantages over other alternative ground protection solutions, according to Mabey. The non-porous surface does not absorb water and cleans easily, eliminating cross contamination. They weigh less than wood mats and allow for more mats per truck load, reducing trips and cost. Matting minimizes surface-bearing pressure reducing impact on soils and vegetation, improving restoration efforts after removal.
Mabey mats support loads up to 600 psi, are durable in extreme climates and have a lifespan in excess of 12 years for Dura-Base mats. Mat design and characteristics have buoyancy to keep crews and equipment safe and drier. The non-skid surface on both sides of the mat reduces safety hazards of slips and trips, Mabey said.
Strong and stable
Lampson International offers steel crane foundation mats for lease or sale individually or as part of an equipment rental package.
Standard 4 by 16 foot steel crane mats are constructed of fully welded 8-foot by 12 inch steel tubing and are fabricated with internal forklift pockets for ease of unloading and placement, according to Kate Lampson, director of public relations and communications.
“These steel mats allow for better ground-bearing enhancement as well as resistance to moisture and rot commonly seen in wooden mats,” she said. “‘Mudboats’ are constructed of 14 by 159-pound wide flange I-beams welded together with integral moment pin connections at each end, allowing the mats to be structurally linked together for a continuous load transferring surface.”
Lampson’s mats can be fitted with transition ramps to allow usage as loading and unloading ramp systems, for shore-to-barge operations or other situations. They can also be used for conventional and ringer crane foundations as well as jacking operation foundations.