Factored load or un-factored load in deflection calcs?
Factored load or un-factored load in deflection calcs?
(OP)
I would like to double check with you guys, that in deflection calculation we should use un-factored load no matter it is a concrete beam or a steel beam, am I right?
Thanks a lot!
Thanks a lot!






RE: Factored load or un-factored load in deflection calcs?
RE: Factored load or un-factored load in deflection calcs?
RE: Factored load or un-factored load in deflection calcs?
RE: Factored load or un-factored load in deflection calcs?
Also, remember that if this is a concrete beam then you should take into account some level of cracking. That applies even when you look at servicability deflections.
RE: Factored load or un-factored load in deflection calcs?
Creep effects in concrete and timber are dealt with by factoring the load in my experience.
RE: Factored load or un-factored load in deflection calcs?
A star for your post, apsix.
That said, it is NEARLY always unfactored for SLS, factored (check what factors, etc) for ULS.
Cheers,
YS
B.Eng (Carleton)
Working in New Zealand, thinking of my snow covered home...
RE: Factored load or un-factored load in deflection calcs?
RE: Factored load or un-factored load in deflection calcs?
RE: Factored load or un-factored load in deflection calcs?
What code deals with concrete creep effects by factoring loads? ACI deals with it by factoring the service deflection by a TIME-dependent factor, not by factoring the loads. That makes more sense since deflections are a serviceability consideration. If you use factored loads then you're also including additional cracking in the calculations. Maybe the procedure has been normalized to account for this, but the idea, in principal, doesn't seem intuitive.
RE: Factored load or un-factored load in deflection calcs?
we normally use factored loads for concrete
2.4G + 1.26Q
RE: Factored load or un-factored load in deflection calcs?
RE: Factored load or un-factored load in deflection calcs?
If in AUS and US during am hours of the summer solstice, the deflection load factors are < 1.0. However, if in UK and CAN during pm hours of the winter solstice, the deflection load factors are > 1.0.
just kidding.
RE: Factored load or un-factored load in deflection calcs?
RE: Factored load or un-factored load in deflection calcs?
hows the work in new zealand.
I always thought it would be need to do a year there.
RE: Factored load or un-factored load in deflection calcs?
All the negative economy stuff aside, I love living here. Professionally it has been very good, given that the focus in Structural Engineering here and in Canada are so different. This has meant training with a focus on timber and steel, with vibration and snow being major concentrations while I worked in Canada, and practicing in predominantly concrete and cold formed steel with earthquakes as the (typically) governing seismic case. I feel it has made me a stronger, much more well rounded engineer.
Back to the topic at hand: In NZ practice we use a weighted live load to dead load balanced load check to simulate long term deflection under NZS 3101, and it is surprisingly accurate. I'll scan and post the appropriate section.
Cheers,
YS
B.Eng (Carleton)
Working in New Zealand, thinking of my snow covered home...