Crane Lift Chart and Tipping

M_{tip} = W_{crane} x_{C G} \geq FS \times W_{load} r, chart governs

The manufacturer’s load chart (radius, boom length, configuration) governs — not a back-of-envelope tip moment, except conceptual FS against tipping (~75% of tip as a crude check). Outriggers fully extended. Never exceed chart.

$r$: Operating radius
$W$: Lifted load (with rigging)

Step-by-step solved example

Chart allows 12 kip at 40 ft. Load 9 kip + 0.5 kip rigging. OK? Next chart cell 8 kip at 45 ft — can you boom out?

Crane boom as a cantilever: capacity drops as radius grows.

1. At 40 ft
9.5 < 12, OK.
2. At 45 ft
9.5 > 8, NOT permitted.

Answer: OK at 40 ft; not OK at 45 ft

10 practice questions

0/10 correct

1.Gross load includes

2.Increasing radius generally

3.On outriggers vs on rubber

4.A 75% of tipping-load rule of thumb is

5.Wind, tag lines, and a swinging load

6.If the chart says 0 at that radius, the lift is

7.Boom length vs radius: capacity is read at

8.Power lines: OSHA requires

9.Pick-and-carry on rubber is

10.9 kip load, 3 kip block+rigging: chart must allow ≥