Designing a high-rise building. 2

[FrustEng]

I’d like to hear especially from those who have experience in designing high-rise buildings. We are going to design a 26-story high building. It is our first of this size. What are the most significant considerations that we have to keep in mind? We have not decided yet the type of lateral resistant system that we will use. How difficult is such a project for the first time, if any?…etc.

Thanks

 

[14159]

You're going to have to provide other details before you can expect intelligent responses. Some obvious questions are:

1. What is the occupancy? Condo? Office?
2. Is there a strong preference to concrete or steel?
3. Will the building be in an area with high spectral accelerations?
4. Will the building be in an area with high winds?
5. Are you in an area of poor or good soil/rock?

DBD

 

[AggieYank]

FrustEng, the obvious things I can come up with off the top of my head to think about are:

1) inter-story and total drift.
2) overturning uplift force on base connections.
3) base shear (due to wind / earthquake).
4) Small planes.

 

[STR04]

Are you going to have a wind tunnel study done? This procedure can save an owner a lot of money for cladding.

 

[SacreBleu]

I would hire a part-time consultant to give you guidance.

 

[14159]

It's probably good that laypersons don't read these forums!!

I definitely don't intend disrespect to the original poster (because I've been there...) but I can't help but wonder if surgical message boards contain analogous questions like: "I've performed minor surgery for 10 years and just landed a brain surgery that I have to perform soon. Any advice?"

Kinda puts the whole structural engineer vs surgeon payscales into perspective. I won't be complaining about that any more!

I like the idea of hiring a consultant to help you with this project. Somebody could get you going pretty quickly and check your work. I think you owe it to the public.

DBD

 

[FrustEng]

Ouch.. this last response really ...stings.

Well, Engineers and brain surgeons are incomparable. That is why a 10-year experienced engineer is paid only a fraction of what a new graduate brain surgeon is paid.
Four thousand years ago Man built pyramids, towers, bridges, and all kinds of structures relying on basic engineering concepts and principles. Those structures are sometimes of complexity more than a 26-story building.
In the thirties of the last century, engineers built skyscrapers without having computers, sophisticated software, absolutely no wind tunnels, and not even calculators. They basically relied on the principles and basic concepts of engineering.
As to our 26-brain surgery, I mean storey building , we are intending to hire a consultant to get help.

 

[14159]

Sorry!

I didn't mean it to sting, really. I was trying to make a general comment about the way things are done, not slam you or your firm. I should've thought more about how it would affect you personally and not typed it.

Again. I am sorry that it came off in a hurtful way. I thought it would be interesting but it wasn't worth it.

DBD

 

[STR04]

It's better to ask than be negligent. That is the purpose of the forum, right?

 

[JAE]

A pyramid is more complex than a modern 26 story building which must meet building codes, ASCE7 wind and seismic, multiple load combinations, a myriad of ASTM requirements for materials, zoning restrictions, energy codes, fire marshall reviews, vibration analysis, electrical systems tied into computer control systems tied into the HVAC system, security issues, tie-ins to sewers, phones, cable TV, etc. etc. etc.

...I think a pile of rocks (i.e. the pyramid) is a lot safer and in addition, pharoah could simply kill any lawyer that got in his way.

 

[pba]

When does a building become high rise?

26 storeys probably is, but we looked at a 15 storey building and the specialists we consulted did not class that as high rise.

 

[flamby]

Depends upon locale. 26 is quite a high rise in New Delhi and we call them sky scrapers of Delhi!

Ciao.

 

[LPPE]

From what I've heard, about 20 stories is the limits for conventional steel shape columns. Now you may have to get in to some sort of hybrid or custom system with 26 stories.

 

[HgTX]

Arguments from antiquity are not valid in today's context. Engineering back in the day was done by making things really, really huge to take anything that might be thrown at them. That's why the Brooklyn Bridge is still functional under modern traffic loads (or so I am given to understand). "Throw a lot of stone/steel/concrete at it" is no longer an acceptable (economically viable) engineering technique.

In FrustEng's defense, there's a big difference between "I've been designing sheds for 10 years and just landed this 26-story high-rise" and "I've been designing 10-story buildings for 10 years and just landed this 26-story high-rise".

Hg

Eng-Tips guidelines: faq731-376

 

[pba]

HgTX,

For the sake of argument - I'm not sure I agree. Throw a lot of stone/steel/concrete at it may not be the best approach but I still see this kind of designing on a regular basis. I may even admit to following that ethos myself on occasion...

Sometimes clients wnat so much flexibility that the more typical rational analysis process breaks down.

I don't see it very often of the larger projects and would agree that it would be an especially inappropriate technique for this high rise.

Best regards
PBA