typical values for vertical load for each storey

[killswitchengage]

Hello my question is simple as the title state it , for obvious reasons related to modeling off buildings for geotechnical engineering , i am looking for typical values per storey be it for RC or Steel structures
thanks

 

[JAE]

There are no typical values as each building has a variety of ranges of dead, live, snow, wind, etc. loads.

Also exterior walls/skin can vary greatly....think glass box vs. block and brick veneer.

Ranges are pretty wide -
Dead Load - perhaps 15 psf to 85 psf for floors
Live Load - 40 psf to 250 psf (code values for different occupancies)
Snow Load - 0 to perhaps 100 psf (usually in the range of 20psf to 40 psf in most parts of the USA)
Seismic/Wind Loads - can have very wide variations for footings depending on the lateral resisting system.





Check out Eng-Tips Forum's Policies here:
faq731-376

 

[thaidavid40]

I agree with JAE's assessment. If you really want to have a "rule-of-thumb" value to go to, you really need a set of values. It would make sense to have a few defined types of structures, with typical loads, to use as background data. That is assuming that these are all going to be in the same general locale. IF the locales will vary widely, then the set of data points just got larger.
Dave

Thaidavid

 

[dhengr]

Killswitchengage:
That’s the kind of question that kinda puts the cart before the horse. As mentioned above, for a given building, materials used for construction, etc. we can tell you what the approx. DL’s per sq.ft. will be and we can tell you what the various LL’s, and snow, and lateral loads will be in a given location. But then, as Structural Engineers, we need you to come into the picture to tell us what the foundation loads can be, with due consideration for max. bearing capacity, long term settlement, soil/found. EQ considerations, etc., because these inputs from you will help us set our max. column spacing, load bearing spacings as we look at our framing system, and thus, the magical loads you are asking for. It takes us Structural and GeoTech guys working together, in unison, to make the final determination. If you want this magic number for your own use, you would be better off taking the last thousand buildings you have done the GeoTech work on, and categorizing them by story height, building type, material of construction, etc., and using that as some guidance for your needs.

 

[killswitchengage]

Its difficult to get experience when you are not a structural engineer. Anyway, the building i am thinking of "may" be an RC structure with 13 storeys , walls made off bricks , with no snow to be foreseen in the region and a raft mat foundation may be chosen . But i am just speculating , prob is we face old and usually small building that we need to bare in mind when conducting geotech computations especially for slope stability.

So i get that the 1 ton / m² / storey is not true !

I must also ask about the effect of long term settelement on the design of the structure, does it effect the design of beams and columns ?

 

[JAE]

Only if the settlement isn't uniform across the building. If the whole building settles the same on its entire footprint then the beams and columns don't "know" that they are closer to the center of the earth.

Check out Eng-Tips Forum's Policies here:
faq731-376

 

[thaidavid40]

In this neck of the woods, the structural engineer will give the geotechnical engineer some presumptive footing and foundation or pile loads so he can estimate the load effects on the soil (or rock) strata. In the right kind of world, you really shouldn't have to be asking this question anyway. Are you having to come up with this type of project information without any preliminary input from the SER?
Dave

Thaidavid

 

[Retrograde]

I find that 10kPa/floor (working load) is a reasonable rule of thumb for a residential building of flat slabs supported by columns (which is the same as your 1 ton / m2 / storey).

 

[killswitchengage]

thank you all
so lets say i have 100 m² the surface area of the building , so it will be something like 100 tons / storey right ?
@thaidavid40 who will ever guess the load per unit area of any building around you knowing that they were not made with any studies ?

 

[msquared48]

You are only valuing the load at a little over 16 psf for that size building - about 12,000 square feet. That is way too small... you are barely accounting just for the dead load.

As an absolute minimum, I would use more in the range of 60 to 80 psf, depending on the useage. The lower figure of 60 yields 360 tons per story.

Mind you, that figure is just conjecture and as JAE stated, will vary enormously...

If you are looking for just the weight of the building, use 25 to 30 psf - floors, roof and walls. That guestimate will get you closer.

Mike McCann, PE, SE (WA)

 

[Okiryu]

killswitchengage, perhaps a bit late, but found this paper from Poulos. See page 6 for high rise steel building weights based on number of stories. Besides that graph, it is a interesting paper for geotechnical engineers.