Wall Penetration Reinforcement
Wall Penetration Reinforcement
(OP)
Hello,
I am working on a 16in thick CIP concrete firewall for a transformer and need to account for a roughly 10' wide by 2' tall penetration about halfway up the 40' wall. Obviously I am concerned with losing 10' of vertical reinforcement and I need to make a force pathway to either side of the opening. I understand the basic premise of providing extra reinforcement as well as corner bars to form a 'force arch' around the penetration.
Previous projects seem to have used software models to determine the reinforcement, however I always like to have a hand calc to go with that as a sanity check. I can take a stab at producing a calc, however I would love to see if you have any recommendations. Can anyone point me to a reference that deals with this situation, or how you have dealt with proof that your penetration reinforcement was sufficient?
Thanks for your time.
I am working on a 16in thick CIP concrete firewall for a transformer and need to account for a roughly 10' wide by 2' tall penetration about halfway up the 40' wall. Obviously I am concerned with losing 10' of vertical reinforcement and I need to make a force pathway to either side of the opening. I understand the basic premise of providing extra reinforcement as well as corner bars to form a 'force arch' around the penetration.
Previous projects seem to have used software models to determine the reinforcement, however I always like to have a hand calc to go with that as a sanity check. I can take a stab at producing a calc, however I would love to see if you have any recommendations. Can anyone point me to a reference that deals with this situation, or how you have dealt with proof that your penetration reinforcement was sufficient?
Thanks for your time.






RE: Wall Penetration Reinforcement
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Wall Penetration Reinforcement
RE: Wall Penetration Reinforcement
jike, that's the go to for the people around me as well, and I likely will do this - just wondering if anyone has approached this without a model as I know it's been done. Thanks!
RE: Wall Penetration Reinforcement
Do a similar thing for the horizontal span.
The FEM model is the simplest and most accurate.
RE: Wall Penetration Reinforcement
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Wall Penetration Reinforcement
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RE: Wall Penetration Reinforcement
KootK - I hadn't thought of that. However as windload is governing, I would still need a lot of vertical reinforcement so I'm not sure if that would help. I could be misunderstanding your point.
Slide - You nailed it, it's a main xfmr firewall subject to environmental loadings. wind governs
RE: Wall Penetration Reinforcement
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Wall Penetration Reinforcement
RE: Wall Penetration Reinforcement
Using some FEM program to design this wall would solve nothing...you already know there will be stress risers at the corners of the opening.
RE: Wall Penetration Reinforcement
1) above the opening, treat as two 10' wide wall piers with all loads on the wall segments between spanning out to them.
2) below the opening, you've got enough meat that the load can probably spread back towards the middle. This could be handy as you'd essenntislly be back to a full section in flexure,
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Wall Penetration Reinforcement
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Wall Penetration Reinforcement
KootK - thanks for the sketch and your input. Very helpful
RE: Wall Penetration Reinforcement
1. Transformers of this size (several hundred megavolt-amperes) are incredibly efficient, typically over 99.6% efficient. Still, energy loss of 0.4% creates a lot of heat. The transformers are oil cooled, but the oil has to be cooled by fans blowing through transformer-mounted heat exchangers. To maximize heat dispersal, minimal structure near the transformer is essential.
2. The transformer should sit on a concrete pedestal inside a stone-filled concrete pit, top of both the pedestal and pit wall at ground level. The space between the stones provides environmental containment of transformer oil in the event of a leak or failure. The size and location of the pit could make bracing a wall more complicated.
3. The main transformer is a critical point for power generation - there is only one main transformer per generating unit. Transformer failure is rare, but a utility wants quick, uncluttered, and straight forward access to the transformer if a replacement has to be put in service. This point is so important to our company that we purchased a spare main transformer for our largest station. It sits onsite, about 100 yards from the transformer yard, unused but maintained, over it's own dedicated oil containment pit.
The photo below shows a typical main transformer surrounded by the containment pit:
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RE: Wall Penetration Reinforcement
RE: Wall Penetration Reinforcement
www.SlideRuleEra.net
www.VacuumTubeEra.net
RE: Wall Penetration Reinforcement