Plumbing pipe in structural Beam

[Trirdsavani]

Hi,

I am involved in construction Water reservoir and Treatment plant in Alberta, Canada, as an Engineer. As per drawing, all Floor drain plumbing,3" PVC Pipe, should be place in Hunching under the suspended slab. As per contractor request, Project Team allows to place 3" PVC pipe in the beams and eliminate Hunching. Beam length is 7mt and pipe place 1.5mt form on end. Both end of beam seats on walls.
Beam 750 deep and 800mm wide. My?- Does 3" PVC pipe allow to parallel longitudinal? if yes what criteria governs to decide that. I have done beam crossing before but never place pipe n beam. Thanks for your time and really appreciate if you can share your valuable information or expertises.

 

[Ron]

Placing plumbing inside a structural member, particularly longitudinally, is a bad idea in my opinion. What happens when the plumbing leaks? What is the impact on both the plumbing and the beam? If the plumbing is placed anywhere other than the neutral axis, it will be subject to the same load influence as the beam, to it be in more tension, shear, or compression than the plastic can take (and most likely will be).

Find another way.

 

[oneintheeye]

am I reading this right, placed in beam running along the length of the beam?

 

[rowingengineer]

I would cast a larger sized steel pipe (5”?) in the beam and install the PVC into the steel pipe.

An expert is a man who has made all the mistakes which can be made in a very narrow field

 

[Trirdsavani]

Hi All,
Thanks for all replies,
herewegothen - PVC pipe place in beam in long direction. and it is slope too, so its varies in elevation in beam to meet pumping code requirements.

rowwingengineer-i like this idea. 3" pipe easily go through in 5" pipe but would it be complicated at fittings?

Thanks

 

[rowingengineer]

I don't know more information would be required will depend on your layout and depth in the beam ect. This is a question for the plumber or hydraulic engineer on the project. Normally the steel pipe option only works if there are no bends required.

An expert is a man who has made all the mistakes which can be made in a very narrow field

 

[hokie66]

Drainage piping in concrete beams is not wise. The piping has to slope, so it will most likely impact the reinforcement in some way. Just not good practice. The specifications require it to be under the slab, and that is where it should run. By the way, what is "hunching"?

 

[jropert]

Cutting through or otherwise placing "non-structural" items in beams is unfortunately too common in construction (even if the documents state to do no such thing)! I agree with Ron on this one...It is NOT a good idea to run the pipe in the beam as stresses common in the beam may very well not be able to be "matched" by that of the pipe. Installing a larger steel pipe would not be a good idea to try to solve this. Furthermore, the strength of the beam is compromised as you would be replacing concrete with a pipe and not to mention interfere with reinforcing (even if it were to be placed along the neutral axis, which it won't be as you had stated..for sloping).

By the way, just curious, but is this beam to be precast, cast-in-place? I would suggest really getting your structural engineer's input on this as he needs to be aware of such potential decreases in strength that he probably didn't design for.

 

[Trirdsavani]

Hi,

Thanks again, I believe in your inputs.
“Hunching” refer as concrete cover around Pipe. Water treatment plant all plumbing bring it down to under the slab and cast-in place at time of slab pour, which have some reinforcement like U bars and Horizontal bars. It also make easier for plumber to U Traps for Floor Drains in the slab. I can send you photos if you want to see.
Thanks,

 

[hokie66]

Why not just hang the pipe under the slab? That way, you can access it for repair/replacement.