Guardrail Suggestions 3

[dik]

One of my latest projects is a 'U' shaped guardrail (in plan) approx 20' long and 5' deep, open on one of the 20' sides. The client does not want to penetrate the roof for anchorage, and wants it restrained by gravity alone. Other than a small continuous 4 or 5" slab or the use of adhesives , I'm out of suggestions. Can anyone offer any suggestions. I cannot even anchor it to the equipment.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[Enable]

Assume this is for a roofer to do some work near edge of the roof? Instead of a guard rail fall arrest based systems with a bump rail might be the most economical.

If you have to go with a gravity guard rail then I suppose your idea might be best for access / economy. You'll have to be careful about loads though 5" of concrete can overload a roof deck quick.

Another option would be to make a 4 sided box out of W-sections to act as your gravity load and have your guards can rigidly connect to those. The box will provide quite a bit of stability and if the guard is open wind shouldn't be too much of an issue. You might need to put one tie mid-box. Not sure why the one side is desired open but if it's for material transfer surely you could just make a ramp up and over the one leg of the box to get into the work area.

But if you're doing roofing work IMHO as a contractor I'd just anchor to the roof, build a concrete boxout around them, and waterproof the darn thing. Done at the start (so water infiltration not an issue over course of the job) and easy to remove at the end without need to get the waterproofer back. Just cut the anchors and put a little ply on top of tips and done.

 

[phamENG]

Apart from going over the edge and mounting into the face of the building (assuming a suitable substrate like CMU or concrete), a big 'deadman' at the base of each post is about the only option I can think of. Could be concrete or a thick steel plate.

 

[dik]

No... permanent... I thought of a 3 sided 'box' but the main weight is at the guardrail and little contribution from the 5' 'wing' walls... also the flex of the 20' wall. I have no idea of what the capacity or the construction of the existing roof is at this point.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[Enable]

Who exactly is the client here? A permanent structure on the roof, which cannot be fastened down...if at all possible this might be one of those clients you tell to come to reality or get lost. This is a liability issue all the way. What happens when you are relying on anything for gravity (deadmans, box beams, concrete slabs, etc) and some roofer comes to move it / chip it to do some work in 5 years but doesn't replace it because they don't know it was an integral part of the guardrail system?

If this is a must go then maybe W-sections underneath the 3-walls (rigidly connected) with studs and pour concrete around to encapsulate. The concrete will aid weathering, add some mass, and not look as funky. Overloading the deck may still be an issue though. Perhaps if it was acceptable design this as an elevated area (make your guards higher to accommodate) and that way you wouldn't be stuck with a 3 sided structure but could make the bottom box 4 sides + infill beams. Top surface to be removable in case of required maintenance to roof below. Math may check out horribly though, just a spitball.

 

[JLNJ]

I think there are systems out there for ballasted guardrail made specifically for roofs.

 

[jayrod12]

skyline group has a cantilever type guard system. I believe it was installed on the roof at Sisler High in town here. Essentially they sacrifice available space on the roof by having U shaped frames every 6 or 8 feet and then run a rail between them. The u-shaped frames have weights on the interior foot, and rotation is considered about the outside foot.

 

[HTURKAK]

Instead of U shaped, can the square shaped with 20' long be an option?

In that case, you may set a square frame made up of box ( 2X6 in etc..) and may fix the pipe handrail on that and may connect frame from four corners only ..

 

[Enable]

Well, those are neat and seem great even for temp works. Thanks jayrod!

 

[dik]

Thanks Jay... I've suggested to my client that his client approach them to see if they can work. I look at my job as finding solutions, evenif I cannot do it myself. I might not subscribe to the solution, but...

Thanks to all... I think this is closed...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[Brad805]

Simplified Safety has a few ballasted roof guards as well. We have used those after a roofer point them out. Link

 

[dik]

Thanks, I've added it to my library... I have difficulty imagining how the ballast resists 225# @ 3'6... unless it ties a bunch of additional adjacent posts with it... Not sure how to analyse that without using 3D frame program...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik