The Customer’s Business
Connelly Crane Rental Corp., Detroit Mich., is a 75-year-old regional crane rental company serving Michigan, Indiana, and Ohio. Its fleet includes boom trucks, RT cranes, AT and truck cranes, and crawler cranes. For years the company has used timber mats and steel plates for ground support under their larger cranes.
“It is important that cranes with outriggers be set up on some type of pads,” said Joe Estep, Operations Manager. “When it comes to crane accessories, outrigger pads are fundamental.”
The Need for a Solution
When the company purchased a 265-ton Liebherr LTM 1220-5.2 all-terrain crane, Operations Manager Joe Estep, considered his options for ground support materials. For cranes the size of Connelly’s new Liebherr, previously the company had used timber mats with steel plate. However, there are certain disadvantages to these materials.
Wood is a natural material that can crack, break, or splinter when put in use:
- Once in the field, wood experiences stress from equipment loads, varying soil conditions, and exposure to the elements.
- Wet or arid conditions, hot or cold temperatures cause wood to degrade quickly.
- As wood absorbs moisture, it correspondingly increases in weight.
- Wood outrigger pads last for as little as one use up to a couple of years. On a ten year timeline, typically a wood outrigger pad will need to be replaced up to five times.
- Wood and timber cribbing is increasingly being limited by site managers on job sites.
- OSHA is paying closer attention to crane setup. OSHA has said that cranes must be setup on firm ground that’s been sufficiently drained and graded, while also using supporting gear like blocking, pads, and crane mats. For more, see OSHA 1926.1402. Using an engineered outrigger pad with known properties, although not required, makes communication with compliance officers much easier.
While steel is proven to have high strength properties, its primary drawbacks are weight and corrosion:
- Increased weight means increased transportation and labor costs.
- Internal welds on steel crane pads are susceptible to corrosion and fatigue and are not easily inspectable. In addition, steel can bend and suffer permanent deformation.
The Decision Process
Estep says contractors are becoming increasingly aware of the importance of proper crane setup.
“They may not fully understand the dynamics behind it, and often request solid matting, when blocking or cribbing would suffice. However, there seems to be a trend that customers prefer to see solid mats under the outriggers,” he said.
Estep performed a cost-benefit analysis between FiberMax® crane pads and timber mats. Because of wood degradation caused by moisture, stress under load, and other environmental conditions, Estep typically replaces the timber mats every two to three years at a cost of $3000 to $4000 each set. In the last 15 years, he has replaced the timber mats used with the company’s larger 360-ton Liebherr at least seven times.
“That’s $25,000 to $30,000 just on wood mats, not considering the labor to configure them,” he said. “Over a 15 to 16 year span, I figured I would spend the same amount on replacing timber mats as I would on investing in the FiberMax crane pads. Plus I will save on labor and transportation costs since the FM8x5x10 Mega Duty crane pads only weigh 1,285 pounds each, about 60% less than what we had been using previously.”
DICA team proposed two solutions using the data supplied by Estep, which included the LTM 1220-5.1’s maximum outrigger forces of 265,264 pounds, outrigger float dimensions of 24 in. square, and maximum outrigger pressure of 460 psi.
“Based on the maximum outrigger reaction force for the crane, a 10” FiberMax pad was needed to provide the rigidity and strength necessary to support the potential 265,000 lb. force. To determine the outer dimensions of the pad (the pad area) we reviewed Connelly Crane’s typical operating environment. Ultimately, Connelly Crane selected the 8’x5’x10” crane pad. This ensured that their average Ground Bearing Capacity (GBC) would not exceed 5,000 psf when outrigger reaction forces stayed under 200,000 lbs.,” explained Joshua Ford, DICA Fitting Specialist.
Benefits of FiberMax over Timber and Steel:
- Engineered: Made of engineered materials, FiberMax will not rot, delaminate or degrade.
- Life Span: FiberMax has a 20+ year lifespan. “Over a 15 to 16-year span, I figured I would spend the same amount on replacing timber mats as I would on investing in the FiberMax crane pads,” said Estep.
- Strength: FiberMax is as strong as steel. Bi-directional internal I-beam design of FiberMax was originally developed for vehicle and pedestrian bridges. This design is what allows FiberMax pads to distribute concentrated loads over large areas to effectively reduce ground bearing pressures.
- Transport: FiberMax weighs up to 70 percent less than steel, resulting in significant transportation savings. Users of FiberMax crane pads consistently report being able to eliminate 1 truck, trailer and employee per job. On jobs 50 miles or less, that’s typically a $500 savings each way. For jobs that extend thousands of miles away, users have reported saving $5,000 each way.
- Labor: Equipped with specialized lifting hardware, up to four FiberMax pads can be lifted into place at once, reducing setup and tear-down time.
- Professional: Standard features include float placement target, hi-visibility non-slip surfaces, high-contrast steel frames, safety striping, and serial numbers with personalized rating plates, which presents a professional message to site managers and customers.
The new crane outfitted with the FiberMax pads has completed several jobs within the first month of delivery. One of those was lifting a 150,000-pound piece of machinery out of a steel factory in Dearborn, Mich. “The operator and crew couldn’t be happier,” said Estep, primarily because the FiberMax crane pads are easier to handle—they weigh half as much as wood and steel plate, which makes them easier to set-up. The crew also said they have confidence in their setup and like that the crane pads look professional.
Based on the performance and cost savings of the FiberMax product, “This was the first set of FiberMax crane pads we’ve purchased, but they won’t the last,” said Estep.