11th edition is not very good at all. I don't know what they were thinking when they printed it.
namely:
1. a lot of good charts are no longer in there (two way plate/cantilever wall charts)
2. a lot of the charts are hardly legible!! it's as though they photocopied the charts.
a poor update.
I am surprised no one has commented on this yet, but note the location of the failure - the corner.
It'd be interesting to see what wind code requirements were around for tall buildings at the time.
Clearly, the corners will receive the higher wind load due to wind vortices. I don't think it's...
Would it be fair to say that the inner envelope is analogous to the failure which is observed in the testing of cylinder strength?
i.e. splitting / shearing failure of the edges.
Typically, this leaves two 'cones' of concrete.
I'm trying to understand the reasoning in the bearing capacity calculations used in a number of concrete codes, where confinement can be taken to aid the bearing capacity (i.e. by a factor of sqrt(A2/A1), within limits).
Does anyone have any papers/tech info in regards to the testing (or...
Josh's method is basically the 'twin beam' theory presented in some texts.
However, I've only ever seen it as saying to ignore the web and simply take the torque out in the flanges.
Would be interesting to see some fancy FE comparisons.
Hokie,
No offence, but you may have missed the point. After trawling through the theory, you/we still don't know where "2%" is from. Which is the original question. And it still isn't answered.
The concept has always been the same - applying some manner of spring stiffness theory. But as...
So in summary, it appears as though someone, somewhere has determined that 2.5% of the axial load justifies a stiff enough brace to supply full restraint to the section.
The ACI code currently covers this problem quite comprehensively - a building's resistance to poltergeists is proportional to the square of a typical wall's thickness.
You simply work out the wall's Ghoul-factor (t^2*gamma*H) where t=thickness(m),gamma=density(kN/m3),H=height of wall(m).
So...
BARetired,
That is harsh, unnecessary and uninformed criticism not required in forums like this.
With 'black-box' computing probably rife in some areas of engineering these days (only due to the rediculous timeframe engineers agree to design projects now), it is better that someone asks the...
asixth,JAE,
Let's say that the crack formed directly over the support centreline (point of maximum negative moment).
The joint then acts as a pin and allows rotation - so it would then act as a simple support which has already been allowed for...
If it's a highly loaded slab I would agree...
Galambos,
Thanks for that. The info appears to cover the steel shear capacity of the mesh itself.
I'd be interested to know if there are papers on beam shear tests with mesh as reinforcement.
Cheers
Hi All,
Does anyone have experience in using mesh as shear reinforcement for beams?
The Australian code AS3600 requires the wire ends to be hooked or to have 2 of the transverse wires in the compression zone.
The main problem I am having is my compression zone is only 100mm (4") from the top...
I have had a quick flick through the comments.
What amazes me is that no one seems to mind actually being judged and stamped with a score.
A numbering system is a pathetic means for reviewing someone's performance - humans are not examination papers.
StructuralEIT,
Not familiar with the Green Book (I'm in Australia), but it would be odd if there is already a 'phi' factor (material/strength reduction factor) as well as the halving which you describe.
The only thing that would make sense is that the conc/steel force component is being...
I was referring to a plate which is fully and continuously supported along the supports - no discrete supports such as columns. Essentially, a slab spanning between continuous walls.
I didn't factor in poisson's effect.
How relevant is this effect? I guarantee 90% of design engineers would...
I have noticed when modelling a simply supported plate in an FE package, I am getting moment actions transverse to the main span. (I am just testing the software).
When the deformed shape is checked, the free edges deflect slightly more than at the midspan, which is consistent with some form of...
The basic principle of the Equivalent Frame Method (EFM) is that the floor plate is divided into panels along each column line. Each panel is then divided into column and middle strips, the total moment over the panel being distributed by a factor into each strip.
FE Packages now provide tools...