Post tension slabs in Mixed Use... 2

[KevinChez]

I recently moved to California and see many mixed use buildings (less than 5 stories) that are parking garages underground, retail on the ground and apartments/condos on top. The construction appears to be concrete columns on the lower levels and then wood framing for the residential.

What's a good way to learn how to design one of these? I am a PE with my own small firm so I would like to be available to design one of these but am not sure where to start. And what would be the professional way to get started? I would not put my stamp on my first design. I would probably have a peer review and pay a seasoned engineer to guide me along?

Thank you,

Kevin

 

[phamENG]

For the wood portion, this document is a pretty good place to start: Link

When you say small, how small do you mean? If it's just you...maybe go get a job with a firm designing these for a bit. Or make some contacts at larger firms with too much work and see if they'll sub some of it to you. That'll be a hard sell without prior experience, though. If you have a firm of a few engineers, or it's just you and you want to expand, try hiring somebody with extensive knowledge in it.

You'll be hard pressed to find somebody who will teach you how to compete with them. Subbing a post tension slab is one thing, but getting a how-to on an entire building type is probably stretching it.

 

[driftLimiter]

We have a practice where we do alot of light-frame and steel design. When we have podiums with PT slab we outsource the PT slab design then we design the concrete vertical elements, and the light-frame building above. As with any building type there are certain dos & don'ts for podium buildings especially the details. For example ([link]https://www.structuremag.org/?p=20682[/url]), many designers have been using Rigid diaphragm approaches to shed load away from the exterior walls (lots of windows) and into the interior corridor walls. There are also shrinkage concerns with the PT slab that need be addressed with good detailing. Congestion of reinforcement for the PT deck may cause some headaches with the light-frame hold down anchors. We had a pretty good discussion going about dual stage analysis and the drawbacks on here a while ago [link]

https://www.eng-tips.com/viewthread.cfm?qid=493817

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[KevinChez]

@phamENG...by small it is just me.

Thanks for the info.

@driftLimiter...it's the details and the "do's and don'ts" that concern me. Thanks!

 

[driftLimiter]

Well @KevinChez The first podium I had to do, we designed the PT slab as well. And I hadn't done any PT work in the past so I spent alot of time in webinars and scouring eng-tips to feed my brain. Truthfully though without a past project's drawings and details I would have probably missed the more nuanced detailing.

There is a lot of info on eng-tips and throughout the literature in our field on these types of buildings as they are becoming very common. Maybe you could find someone else locally to team up with on your first one, particularly if they have past experience and drawings/details you could reflect on.