1 Ton Hoist Calculation
1 Ton Hoist Calculation
(OP)
I am putting a 1 Ton hoist up. It is a 16 ft length and 15 ft high. We have a base of 32 in square 3/4 inch thick steel. The base is anchored to a poured concrete slab that is at least 8 inches thick. The 8 anchors are rated at 9000 lb in tension. The moment at the top of the beam is M=Fd= 32000 ftlbs. so how do I figure the amount of resisting moment is needed and if the 8 anchors will be enough?






RE: 1 Ton Hoist Calculation
RE: 1 Ton Hoist Calculation
Is it supported on a structural slab above grade or slab-on-grade?
If it is at grade, you need to provide a square footing with enough weight to exceed (counterbalance) the overturning moment by a factor of safety of two. You would also need to check the soil bearing pressure under the footing. Jib crane manufacturers will sometimes have a suggested footing size that you can use as a starting place or you can do it by trial and error.
You should calculate the actual tension in the anchor bolts and then make sure that it cannot pull out of the concrete or yield with an appropriate factor of safety. ACI 318-02 Appendix D can give you some guidance.
RE: 1 Ton Hoist Calculation
Thank you
RE: 1 Ton Hoist Calculation
Regards,
Jeff C.
RE: 1 Ton Hoist Calculation
Does the rail structure provide bracing in both directions, or just one? I would hope that you would want bracing in two directions.
RE: 1 Ton Hoist Calculation
RE: 1 Ton Hoist Calculation
RE: 1 Ton Hoist Calculation
RE: 1 Ton Hoist Calculation
A little caveat based on an incident that I observed a few years ago. A similar mounted jib (3 ton) crane along with a newly installed overhead crane 15 tons vs original 10 ton with supposedly completely rerated support steel came crashing down. Fortunately only feelings were hurt. In short the overhead crane was at its capacity? along with the jib? at capacity. As the overhead passed the jib something moved and overhead came down. The support columns were free standing with only X bracing. 3 columns had to replaced. I didn’t get to see how they were bent
The report on the incident wasn’t made public. There were all kinds of tales about the incident such as the new beam crane was 2" short and the had 1" spacers ready to install on the crane rail support offset brackets, there were already had 1" spacers under the brackets. Another was that the base plate bolt holes had been slotted, they were, I saw them in the scrap pile. Another was that both cranes were overloaded at the time, probably based on what was on the shop floor at the time.
To top it all off the company that done the design and supervised the redesign and installation of the new crane conducted the failure investigation.
Here is some information on Jib cranes. These people always seemed quite helpful when we used them.
http://www.caldwellinc.com/kk.htm#walljibcrane