Moments Redistribution
Moments Redistribution
(OP)
Is possible to redistribute negative moments at the end of supports in a beam-frame structure?
When was the last time you drove down the highway without seeing a commercial truck hauling goods?
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RE: Moments Redistribution
14159
RE: Moments Redistribution
RE: Moments Redistribution
For parking garages, I've used a 20psf live load for determining col and endspan bm moments, then used regular 50 psf loading for the balance of the frames.
Dik
RE: Moments Redistribution
RE: Moments Redistribution
A lot of cracking resulted - no fun at all.
RE: Moments Redistribution
Dik
RE: Moments Redistribution
How do you figure that? We figured the upper side of the beam was in tension near the supports, and the concrete shrinkage during curing aggravated it.
RE: Moments Redistribution
One computer program widely used for PT design immediately reduces the moment difference either side of columns to zero when redistribution is asked for. This is completely illogical when you think about punching shear design. Redistribution should require that the moment attracted to a column remain the same no matter how much redistribution is allowed for either side of the column.
Other things that need to be checked when redistribution is allowd for are increased ductility limits for strength design and also the effects on crack control. The deemed to comply crack control rules in ACI cannot be used in this case as they underestimate the stress in the reinforcement in areas where moments have been distributed away from. Add SacreBlue's restraint stresses to this and you have real problems unless all of this is allowed for properly in design (and it is not by most designers, often due to a lack of understanding of the basis of code clauses).
RE: Moments Redistribution
Dik