Live Load of 30 Workers?

[Yoidles1]

i need to design some brackets to support a truss and 30 boilermakers while replacing the boiler wall that supports the truss in normal service. They have installed scaffolding on top of the truss, and the superintendent will have no more than 30 people working from the scaffolding at one time.

How do i determine the live load to include for 30 people?

 

[JedClampett]

Maybe you think us structural puds have some magic boilermaker live load formulas, but what I would do is multiply their average weight (200 lb.?, maybe 250 lb. after beer and brat night at the pub) by the number of them. I get 6000 to 7500 lb.
Alternately, you could get the area of the scaffold and multiply by 100 psf.

 

[ishvaaag]

If I were to design that and no code, I would likely use someting like for roofs, say 100 kgf/m2 overall and say no less than single 150 kgf point load anywhere. If that proves too much, and again, no code ruling otherwise, you can make each worker 150 kgf (that makes for some minimal impact forces) and place at worst places. Since construction work a 1.25 to 1.35 safety factor, no less, for this load.

 

[Yoidles1]

Boilermaker live load isn't in your code book?

i just wasn't sure if typically a factor would be included to accomodate more than the static weight of the people occupying the surface.

 

[jberg]

I have done the 100 psf live load times the scaffold area, but if you have multiple levels, the total load can get excessive. This happened to me on a boiler scaffold support framing I designed last year where the scaffold only had 20 or so workers, but the scaffold was over 8 levels tall, if I remember correctly.

Simply multiplying the scaffold area by 100 psf and then taking the number of levels into account was much larger than 20 or so workers the scaffold would be subject too (I normally assume 300 lbs per worker to account for tools, misc equipment, etc).

Hope it helps,

JWB

 

[ishvaaag]

This past summer I had to design a boiler room for some colleagues. Boilers and equipment in the end were to be placed on steel plate and the rest was steel grate. We used about 750 kgf/m2 for the grates locally, above 500 kgf/m2 in general, and I think well over 5000 kgf/m2 and more (do not remember exactly the figure) to take full boiler weight, and full safety factors, 1.6 for live. Of course the high live loads in the steel grate part was not on the requirement of the weight of the workers, but on the experience that when moving mechanical equipment flimsy floorings get damaged and the thing was left at that values without any objection at that. Even so our more rational design (not a tight one, as you see) nearly halved the steel weight initially proposed by a third party.

I examine the CTE code (Spain's) and there's no explicit live load allocation for this situation. ASCE 7-05 you choose in table 4.1 and

"4.7 IMPACT LOADS
The live loads specified in Sections 4.2.1 and 4.4.2 shall be assumed to include adequate allowance for ordinary impact conditions."

I have also practiced the worker loads at the lower ranges quoted in my previous post in HVAC equipment context on laminated wood flooring. Even then we didn't just use the purportedly actual weight of the workers but I think to remember 200 kgf/m2.

 

[msquared48]

Not being fecious here, I would assume 10K for the thirty boilermakers. Serious.

However, the CG of a boilermaker is relatively low, so I would ignore any impact. I would include a 1.25 sloshing coefficient though.

Mike McCann
MMC Engineering

 

[csd72]

How much tools and equipment will they need to bring with them?