If you consider that 100% of crane and maximum load may be exerted on any one outrigger pad at any time you can plan for proper outrigger set-up. It is for this reason that equally dividing the load around the outrigger pads is a mistake. No rules of thumb, no wing and a prayer, no best guess, just a calculation to determine the size of cribbing/blocking required.Ī key thing to remember is that as a crane works and rotates over the various corners and quadrants, the load will shift and at any one time a greater load will be placed on one outrigger than on the others.

So how do you determine what “adequate support” is? You have to calculate it. (2) such thickness, width, and length, as to completely support the float, transmit the load to the supporting surface, and prevent shifting, toppling, or excessive settlement under load Finding “Adequate Support” (1) sufficient strength to prevent crushing, bending, or shear failure For those not in construction, ASME B30.5-3.2.1.5 (i) states:īlocking under outrigger floats, when required, shall meet the following requirements: Nowhere in OSHA does it say that you will be ok if you use the rule of thumb for cribbing, instead in 1926.1402 OSHA states: that cranes must be assembled on ground that is firm, drained and graded sufficiently, in conjunction with supporting materials, such as blocking, cribbing, pads, or mats, to provide adequate support and levelness. We hate to break it to you, but there are NO safe rules of thumb when it comes to cribbing. “I just use the pads that come with the crane, surely that is enough.” “There are no rules, I just stick whatever I have on hand underneath the pad,” “Who cares what size the float is? I go with the crane capacity divided by 5.” “I’ve always used 4x times the float… better be safe than sorry.” Hydraulic truck cranes are also used to lift killer whales like Shamu out of water tanks when places like SeaWorld ship the whales to new destinations.“Well I’ve heard it has to be 3x the outrigger float.” In a matter of minutes, these machines are able to raise multiton bridge beams on highways and heavy equipment in factories and even lift beachfront houses onto pilings. Hydraulic cranes may be simple by design but they can perform Herculean tasks that would otherwise seem impossible. After the waters receded, emergency teams brought in three large hydraulic truck cranes - one 500-ton, one 300-ton and one 175-ton - to lift the train out of the creek bed and back onto the train tracks. As you might imagine, a 412,000-pound (186,880-kilogram) locomotive is not easily lifted. Floodwaters rose so quickly in Little Sugar Creek that the underpinnings of a train trestle collapsed, bringing a diesel locomotive crashing down into the creek. Heavy rains spawned by Hurricane Danny flooded many parts of Charlotte, N.C. Hydraulic truck cranes can lift thousands of pounds using the simple concept of transmitting forces from point to point through a fluid.

Crane load charts for dummies