Transcript The Effects of Wind on Crane and Their Loads, Matt Gardiner, Haag

Houston Business Roundtable – Feb. 12, 2013
THE EFFECTS OF WIND ON
CRANES AND THEIR LOADS
Matt Gardiner, P.E.
Houston Business Roundtable
PRESENTATION OVERVIEW
1.
2.
3.
4.
5.
Wind Effects
Standards & Regulations
Wind Related Accidents
Lift Planning Considerations
Questions
1
Wind Effects
1
WIND EFFECTS
About wind…
• Wind speeds are measured at 33 feet above
ground
• Wind speed increases with height
• Gusts can be a bigger problem than sustained
winds
• Look for obstructions to wind
• Look for potential areas that funnel or redirect
wind
1
WIND EFFECTS
How does wind affect a lift?
• Wind applies forces directly to the load (sail effect)
• Wind applies forces directly to the crane
• Drift can cause tip-overs or side-loading
• Drift can eliminate clearances with boom or other
obstructions
• Drift (inward) can cause backward instability
• Wind on load can cause load control issues
2
Standards & Regulations
2
STANDARDS & REGULATIONS
OSHA Regulations
• Crane manufacturers, OSHA and ASME provide wind
requirements
• §1926 Subpart CC
– §1926.1403(h)(12) and §1926.1435(b)(4)(iii): Wind effects must be
considered during A/D ops for mobile and tower cranes
– §1926.1410(c)(1): Power line drift from wind when working inside Table A
distances
– §1926.1417(h): Equipment securement requirements from storm warnings
– §1926.1417(n): Capacity adjustment requirements due to wind
– §1926.1431(k)(8)(i): Personnel hoisting requirements – 20 mph at the
platform?
– §1926.1435(e)(6)(v) and §1926.1437(e)(3): Wind indicators required on tower
cranes and cranes on barges
– §1926.1437(m)(1)(ii): Load charts must consider 40 mph winds for cranes on
barges
– §1926.1437(n)(1)(i): Rated capacity reduction requirements (as applicable)
due to wind for cranes on barges
2
STANDARDS & REGULATIONS
ASME Standards
• ASME B30.5 - 2011
– 5-3.1.3.2.1(h)(2): Site Supervisor responsible to ensure potential effect of
wind is addressed
– 5-3.2.1.5(b)(5): The effect of wind on the load and crane has to be noted and
considered
– 5-3.4.5.4(g): For operations within a FULLY ERECTED/EXTENDED BOOM
LENGTH of Table 5-3.4.5.1-1 (same as OSHA Table A), horizontal and
vertical power line drift due to wind shall be added to the minimum clearance
distance in the Table
• Also requires consultation with utility owner to get specific clearances
4
LIFT PLANNING
CONSIDERATIONS
4
LIFT PLANNING CONSIDERATIONS
What does the manufacturer
say?
• Most manufacturers recommend capacity reductions above 20
mph
• Most manufacturers set maximum allowable wind speeds for
operations
• Always consult the operations manual for instructions
4
LIFT PLANNING CONSIDERATIONS
What is the wind forecast?
• Check with reliable sources (NWS, NOAA, official stations)
• Look for peak projected sustained and gust speeds AND wind
direction(s)
• Speeds tell you how much force can be applied
• Direction tells you how the crane and load will be loaded by wind
• Remember that wind forecasts are at a height of 33 feet and your
cranes and loads may be much higher
4
LIFT PLANNING CONSIDERATIONS
Food for thought
• Will the wind generate enough force to significantly move the
load?
• Will the wind generate enough force on the crane’s boom to
jeopardize stability?
• Can the wind cause load control problems?
• Are there nearby buildings that can funnel or redirect wind flow?
• Has the Operations Manual been consulted for limitations?
• Is there anything nearby that can be affected by wind that could
interfere with the lift?
• Are there any on-site weather stations or anemometers?
4
LIFT PLANNING CONSIDERATIONS
References
• OSHA Regulations
• ASME Standards
• Crane
Manufacturer
(Operations
Manual)
• Cranes and
Derricks, by
Howard Shapiro
5
QUESTIONS?