Outrigger Bearing — Reinforced Concrete Slab
Pad pressure vs allowable bearing on reinforced concrete slab, with required mat area.
A healthy RC slab takes 400+ kPa locally — the question moves from bearing to STRUCTURE: what spans beneath? Basement slabs, podium decks and culvert roofs have punched under outriggers rated 'fine' by surface math. Below-grade voids are the first question on any urban lift plan.
Formula
Note: Rigging and crane decisions are life-safety critical. This calculator is a planning aid — the load chart, sling tags, site lift plan and a qualified lift director govern every real lift.
Pad pressure vs allowable bearing on reinforced concrete slab, with required mat area. A free crane load, wind & rigging safety tool — no sign-up, no upload, instant results in your browser.
About Outrigger Bearing — Reinforced Concrete Slab
Outrigger Bearing — Reinforced Concrete Slab computes the governing relationship P = (W_crane + W_load) × share ÷ pad area vs q_allow live as you type. A healthy RC slab takes 400+ kPa locally — the question moves from bearing to STRUCTURE: what spans beneath? Basement slabs, podium decks and culvert roofs have punched under outriggers rated 'fine' by surface math. Below-grade voids are the first question on any urban lift plan. Defaults are pre-filled with realistic values for this exact scenario, and the worked example substitutes your numbers step by step so the math is never a black box.
How to use Outrigger Bearing — Reinforced Concrete Slab
- 1Enter your values — Crane weight (with counterweight), Load + rigging, Worst-case share on one pad, Pad/mat contact area and more (sensible defaults are pre-filled).
- 2Read the live results: Pad load, Bearing pressure, Mat area needed.
- 3Check the "with your numbers" line to see P = (W_crane + W_load) × share ÷ pad area vs q_allow substituted step by step.
- 4Adjust inputs until the scenario matches yours, then copy or share the result.
Why use Outrigger Bearing — Reinforced Concrete Slab?
- ✓Instant, free and private — every calculation runs client-side in your browser; nothing is uploaded
- ✓Built on the stated formula P = (W_crane + W_load) × share ÷ pad area vs q_allow with authoritative sources cited on the page (OSHA 29 CFR 1926 Subpart CC — Cranes & derricks in construction; FEM 5.016 / Liebherr ground-pressure guidance)
- ✓A healthy RC slab takes 400+ kPa locally — the question moves from bearing to STRUCTURE: what spans beneath? Basement slabs, podium decks and culvert roofs have punched under outriggers rated 'fine' by surface math.
- ✓SI ⇄ Imperial toggle converts your inputs in place, so you can work in the units your drawings use
Frequently asked questions
What formula does the outrigger bearing — reinforced concrete slab use?+
It evaluates P = (W_crane + W_load) × share ÷ pad area vs q_allow, exactly as published. Sources: OSHA 29 CFR 1926 Subpart CC — Cranes & derricks in construction; FEM 5.016 / Liebherr ground-pressure guidance. The substituted worked example on the page lets you verify every step against the textbook.
How should I read the result — and how far can I trust it?+
A healthy RC slab takes 400+ kPa locally — the question moves from bearing to STRUCTURE: what spans beneath? Basement slabs, podium decks and culvert roofs have punched under outriggers rated 'fine' by surface math. Rigging and crane decisions are life-safety critical. This calculator is a planning aid — the load chart, sling tags, site lift plan and a qualified lift director govern every real lift.
When is this calculator the right tool for the job?+
Pad pressure vs allowable bearing on reinforced concrete slab, with required mat area. A free crane load, wind & rigging safety tool. Below-grade voids are the first question on any urban lift plan. For neighbouring scenarios, the related tools below cover the same engine with different presets.
Does it support both metric and imperial units?+
Yes — the SI ⇄ Imperial toggle converts the values already in the fields, preserving the physical quantity, so you can flip mid-calculation without re-entering anything.
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