Structural Design for modern apartment complex 4

[KevinC]

Hi all. I am looking to build a modern ~20 floor apartment complex. I was talking to an architect and he mentioned something about using "cable wires for structural beams" as opposed to "traditional beams". Can anyone shed some light on what this would even look like. I can't seem to find good examples of this or a good list of pros and cons for either. Thank you

 

[hokie66]

Architects are not a good source for learning about structural design. He may be talking about post-tensioning, but that is just a guess.

 

[Tomfh]

Sounds like post tensioning

 

[dik]

I've only done one PT apartment bldg... a couple of RC ones and a whole bunch of HC slab ones... PT can be tricky if there's the potential for putting holes through it... You need more info to determine what he's talking about.

So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[Ron]

Yep. Sounds like PT. If you don't do it routinely, leave it to the specialists. Make it a delegated design to the PT guys.

 

[KevinC]

Is it possible to get a 101 run down of cost benefit between PT and RC? Thanks a ton

 

[structSU10]

PT will result in a thinner floor slab than a mild reinforced concrete building. The main thing is PT is a specialty trade and contractors in your area may not be familiar with it.

If PT is a standard construction type where you are than it can be a good way to go - at 20 stories if you can save a few inches or so at each floor level it can add up and save on facade cost, mechanical costs, etc. It is more expensive than mild reinforced concrete buildings but there may be cost savings in the other trades to offset that premium.

It would be a good idea to speak with a local structural engineer or contractor familiar with local practice who can likely help point you in the right direction.

 

[dik]

...and PT has a slightly smaller carbon footprint, too.

So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[hokie66]

Take that bulldust elsewhere, dik.

 

[Retrograde]

PT will result in a thinner floor slab than a mild reinforced concrete building.

Maybe. Often the slab thickness is driven by fire rating requirements.

 

[dik]

Like it or not Hokie, it's fact, and concrete has a high carbon footprint to start with.

So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[dik]

It's been a while since I've done a PT slab, but normally reinforced concrete has the same/similar limitations for fire resistance rating. Most apartments and offices I've done require a 2 hour fire resistance rating and this is usually achieved with a minimum 5" slab and 1" concrete cover, if memory serves (I seem to recall 3/4" cover for some circumstances... but lost in the distant past). Fire resistance rating is normally not a limitation. Perhaps one of the practicing PT guys can add/correct this.

So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[KevinC]

I appreciate all the help. I'm trying to go as "future proof" as possible, being as I'm trying to build a higher end complex. I'd rather have it also have modern and superior insides as well as outsides. A lot of people I've talked to just want to dress up the outside, so I'm trying to make sure everything else is up to snuff as well. If anyone has any (literally any) recommendations for avenues I should research for this project in terms of structural design I'd be grateful.

 

[hokie66]

Just hire a structural engineer in your area. That is where you will get the advice you need, tailored to your needs and locale, as things are different wherever you go.