Is it possible to build a building with 3 levels, with the 2nd and 3rd levels having areas with clear spans (no columns) of 130 ft length and 85 feet width? There can be columns outside of this clear span area and on the first (ground) level.
3 Answers
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Yes, it is possible by using trusses, 2D or 3D. Or special configuration on adjacent span beams such that those beams can cantilever into the clear space by say 25' from each side thus reducing the effective span to 80' by 40' while using high strength concrete and post strees cable or some other expensive complex mixture of these.
One has to consider the very negative impact of wide spans with the top-heavy structure on seismic resistance of the building and extra height of the building to accommodate the depth of 12'-15' deep trusses.
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Auditoriums and arenas have much larger clear spans ; It just takes large steel beams or trusses . The beam sizes will be strongly affected by the loads you plan for the upper floors.
answered Oct 12, 2019 at 19:00
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The answer to this is that, engineers have to come out with different idea / creative solution to increase the span of the slab.
I believe there are many other solutions in other places that not mentioned in the following: 1.) Cold-form steel trusses
2.) Post/Pre-tensioning concrete structure
3.) Arc shape structures support with tensioning rod.
All which to depends on the architectural requirement and technology availability.
