Building Above Ground

[CookPump]

Because our product line serves the oil industry, we are quite busy and needing to grow. As good as that sounds, because of the specifics of our facility it places us in a very interesting position. The facility we occupy was originaly built around the 1890's for manufacturing roofing tile. The entire property is riddled with brick lined tunnels. We are interested in adding a free standing metal building appxly 50' x 100' x 16' eaves. Current building design calls for a foundation with concrete column footings several feet deep. This would require a caving in and compacting procedure that would be quite complex. However, if this building could be built above ground many obstacles would instantly disappear. Would anyone be familiar with a project where a metal building was built entirely on top of the ground, or if such is even feasible? All ideas, comments, and suggestions will be greatly appreciated. K.

[philior]

Hello,
responding to your question about above-the-ground building.
Just imagine that you have a normal building with underground footing, and you decided to waterproof the foundation. What happens when you dig away all the dirt around it? Will it collapse? No. Then, you have virtually what you need - the structure on the surface. All you need is to assure its vertical stability when you design it.
Yes, it also needs a solid bed. If you have a sandy surface you may not be able to rely on it. However, if you create some protection for the ground from running, you can have a safe building. Tropical rains could be a not helpful factor.
Of course. it also depends on its height (or hight-to-base ratio) - you don't build highscrappers this way.

This is my common-sense guess. Check with specialists.
Best,
Philior

[Basri]

As a structural engineer, I see few options to place the columns on solid bearing soil:
1. Put the columns outside the footprint of the tunnel area. Since this is pretty large canopy, you may need to have long span beams/roof trusses to span between columns that are far apart
2. Map the tunnel locations and place the columns away from the tunnels. You may need to ask the geotech to do insitu testing at some of these possible column locations to ensure the soil is stable and has good capacity.

Hope this helps

[SDR]

How about a floor slab made of concrete T's of the kind used in parking structures, etc. These would presumably be able to bridge the irregular bearing condition of the site. Perhaps the anticipated live (floor) load would determine the feasibility of this approach. . .?

Building "above the ground" does not remove the necessity for a stable surface, or reliable points of bearing, to take the dead and live loads of the structure and its contents.


SDR

[nanrehvasconez]

YOUR 50 X100' BUILDING CAN BE BUILD SAFELY BY USING AS IT HAS BEEN SUGGESTED A CAISSON UNDER EVERY COLUMN, STANDARD SPACE OF THE COLUMS IS 20', BUT IT CAN EASILLY BE PLACED AT 25' CENTER TO CENTER, THEREFORE YOU WILL HAVE ONLY 10 CAISSONS AT 20', 8 CASSONS AT 25', THIS IS THE MOST ECONOMICAL FOUNDATION THERE IS. YOU MAY NEED TWO MORE CAISSONS AT THE ENDS, DEPENDING ON THE BUILDING DESIGN.

ALSO, COULD BE BUILD OVER REINFORCED CONCRETE COLUMN PADS, USUALLY 24" THICK BY 5' SQUARE, AFTER THE BUILDING IS ERECTED YOU WILL PLACE A CONCRETE SLAB FLOOR DESIGNED FOR FORK LIFT TRAFFIC, 6" THICK 3500 LSI WITH FIBRE AND REBAR REINFORCEMENT.

YOU MUST CONSULT WITH A SOILS ENGINEER TO GET THE PROPER DATA FOR THE DESIGNING OF THE CAISSONS OR THE CULUMN PADS.

THE CITY OR COUNTY WILL DEMAND THIS SOIL TEST BEFORE ISSUIN A BUILDING PERMIT.

DO NOT GO ON THE CHIP, THE BEST DESIGN WILL SAVE MONEY AND HEADACHES IN THE FUTURE.