Crane Outrigger Pad Size

Crane outrigger pad size is the calculated surface area and dimensions of pads placed under crane outriggers to safely transmit outrigger reaction forces to the ground without exceeding allowable ground bearing pressure or causing pad or soil failure. It is determined by dividing the maximum outrigger reaction force by the allowable ground bearing pressure, ensuring pads are of adequate size, strength, and rigidity per regulations like Alberta OHS Code s.92.2 and OSHA standards.

In shop yards, loading bays, and plant sites, outrigger pad sizing ensures safe crane operation on paved slabs or compacted ground. The process involves: 1) obtaining manufacturer outrigger reaction forces for the planned configuration; 2) determining ground bearing capacity via engineering docs or plate load tests; 3) calculating required pad area using the formula Pad area = Maximum outrigger reaction force / Allowable ground bearing pressure; 4) selecting pads with dimensions meeting or exceeding this area and verifying pad strength/rigidity to prevent excessive deflection; 5) setting up pads on uniform, prepared surfaces with outriggers fully extended. SafeDesk systems integrate these steps into pre-lift checklists and SOPs for compliance with WorkSafeBC and provincial OHS codes.

• ⚠️Using pads too small for actual outrigger loads due to generic rules of thumb instead of manufacturer data, causing ground bearing pressure exceedance and potential soil failure or crane collapse.
• ⚠️Ignoring ground bearing capacity variability, such as assuming paved ground is adequate without testing, leading to overestimation and differential settlement under outriggers.
• ⚠️Using pads with insufficient strength or rigidity, like thin timbers or deteriorated cribbing, causing pad deflection or breakage that unlevels the crane during lifts.