live load definition
live load definition
(OP)
Hi all,
I am working with an OSHA specc on ladders that requires that the rungs be able to hold a 200 pound live load. No acceleration level specified. Can some one explain what is the meaning of live load in this case?
Thanks,
Bob
I am working with an OSHA specc on ladders that requires that the rungs be able to hold a 200 pound live load. No acceleration level specified. Can some one explain what is the meaning of live load in this case?
Thanks,
Bob





RE: live load definition
Absent that, the actual peak load due to a live load is usually taken as double. The theory is that if you suddenly apply a load to an elastic system you would double the strain on it, hence causing double the load.
RE: live load definition
In general it is the varying load, in your case, the heaviest bearing intensity the ladder as an overall structure is capable of sustaining. In buildings, dynamic load usually refers to the maximum number of people the floor can withstand to bring it equal to your design factor of safety.
I would take the fattest possible worker, 250 lbf, and the maximum possible lift capability buddy can handle safely on the ladder, say half his weight. Build your ladder to suit 375 lbf dynamic load, factor of safety of two or three.
Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada
RE: live load definition
RE: live load definition
OSHA ladder regs are based on old ANSI standards, and looking at a less-old ANSI standard, I find it gives AISC-ASD for the allowable stresses for steel ladders.
I seem to recall that the minimum rung size, 3/4" diameter by 16" long, calculates out to be somewhat marginal using A36 steel, but in reality works fine.
You can ask OSHA for an official interpretation, but be prepared to wait months for an answer. I'm still waiting on some ladder questions sent in on February 9th.