Coring through concrete beam
Coring through concrete beam
(OP)
Hi guys,
I have a situation where an existing 600 x 190 beam (24" x 8") needs to be cored so services can pass through. My thoughts are that I should try to do this in a low shear region because the beam is not going to be scanned to determine the location of the shear ligs.
And I should core approximatley within the middle third of the depth, this way I will avoid any tensile steel and the compressive stress block should not be affected depending on the depth of the neutral axis.
What do others think of this logic.
I have a situation where an existing 600 x 190 beam (24" x 8") needs to be cored so services can pass through. My thoughts are that I should try to do this in a low shear region because the beam is not going to be scanned to determine the location of the shear ligs.
And I should core approximatley within the middle third of the depth, this way I will avoid any tensile steel and the compressive stress block should not be affected depending on the depth of the neutral axis.
What do others think of this logic.






RE: Coring through concrete beam
Dik
RE: Coring through concrete beam
Otherwise, the use of a regular percussion drill for the outer 50mm would minimise the chances of coring through reo. Percussion drills dont tend to cut reo.
As per your question, yes I would think it reasonable to located the hole in the middle third, in the middle third of the beams span.
RE: Coring through concrete beam
Mike McCann
MMC Engineering
RE: Coring through concrete beam
RE: Coring through concrete beam
You should be able to locate the stirrups with a cover meter.
RE: Coring through concrete beam
Mike McCann
MMC Engineering
RE: Coring through concrete beam
Hey Mike; Great tip! Love it when someone includes the precise product name. My Zircon is the little black jobby without a screen; Do you happen to know if the new Videoscanner (5.5 is the currently available model) works as well as your 5.0? Just worried they might have reduced the strength, or improved the software for timber which might have limited the general application. Thought I'd ask on the off chance you know...
Cheers,
YS
B.Eng (Carleton)
Working in New Zealand, thinking of my snow covered home...
RE: Coring through concrete beam
Mike McCann
MMC Engineering
RE: Coring through concrete beam
Were the videoscanners bought by your company or did you purchase one for your own personal use?
RE: Coring through concrete beam
A cover meter should be standard equipment in a structural engineering office.
RE: Coring through concrete beam
http://www.wallscanner.de/en/start/index.htm
RE: Coring through concrete beam
Thanks mate, I put it to my company today to purchase a cover meter but they didn't like the idea. So I think I might have to buy a cover meter myself. I might go down the hardware store and see if they sell any down there.
BTW, I have attached a picture of the beam that they want to core through, I have done some numbers on the beam and it looks like it is in a low-shear zone however, I want to try and avoid the shear ligs if possible.
RE: Coring through concrete beam
I wouldnt go out and buy one yourself as they are not cheap, and it is really up to the contractor to do. These can be hired if necessary.
The 'beam' that you show on the picture looks like a ventilation duct to me. There is no chamfer in the corner and on the right hand side appears to be a few creases in the metal. Also it looks nothing like the beam beyond it.
RE: Coring through concrete beam
RE: Coring through concrete beam
RE: Coring through concrete beam
RE: Coring through concrete beam
Sorry, must have been a senior moment. I get you x-guys confused.
RE: Coring through concrete beam
The beam the duct passes through is 600 x 290, the transverse beams that frame through this beam are 450 x 190 at 1450 c/c, and they span to beams that are 900 x 290 and are at 8500 c/c.
Slab over is 100 deep.
This wasn't the best picture to psot so I will post another.
RE: Coring through concrete beam
Steer clear of the edge of the duct penetration as this will have extra shear reinf either end. Also there will be an extra row of horizontal bears at the top and bot of that penetration that you need to miss.
RE: Coring through concrete beam
Based on your photograph, I would guess that the section of concrete you are planning to core through is not a beam at all, but just a dropped soffit to receive the head for a movable partition. I think the joists at 1450 centres span the 8500 between the 900 deep beams.
RE: Coring through concrete beam
Maybe, it appears like what you have described when looking over the existing structural drawings, that the 450 deep beams span to the 900 deep beams with then span onto the columns.
I will post the drawings on tuesday when I get back to work.
RE: Coring through concrete beam
It sounds like someone needs to review the plan to determine the function of the member. With a hole the size of the duct, I doubt there is any flexural load on this member.
RE: Coring through concrete beam
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RE: Coring through concrete beam
RE: Coring through concrete beam
I ran a quick model to determine what magnitude of forces are going through that member and there is significant positive moment due to the curvature of the floor system. Saying that, the shear isn't of significant magnitude.
I don't think there should be a problem with coring through this beam provided I stay away from the tension steel and the neutral axis. And I have the slab x-rayed to map the exact locations of the steel.
RE: Coring through concrete beam
RE: Coring through concrete beam