Hi there,
I'm hoping this will upload correctly, if so please find related model attached, with which I have a couple of questions.
1. My first question is in regards to large reinforcement it places directly adjacent to the inner triangle of walls. There are cores that actually exist in the centre of the slab where there is a large void. Initially I got huge reo (say 200 N16 bars) around the inner perimeter. For the most part it was due to clause 9.4.2 and some was concerning 8.1.5. (both these clauses seem to be the popular reason for reo).
Conceptually I thought this was due to the slab being restricted free "sliding" movement by the inner perimeter walls. I hadn't yet correctly unticked the shear wall box in wall properties to allow the slab above to slide. So I unticked the box to have compression only wall (ie conceptually a roller support?).
However this did not have the effect I intuitively thought. It actually increased the reo outputted around the inner perimeter of walls? The solution to getting rid of the error reo in the end involved decreasing the number of strands in the tendons around the inner perimeter walls?
Why would turning it into a compression only wall do this?
2. The second question relates to clause 8.1.6.1 "minimum strength requirements". It is currently the cause for a lot of the remaining reo in my model which I need to get rid of (it is expected that I only have reo around the perimeters and edges, none running the same span as the tendons, which I have a little of at the moment).
It reads Muo.min = 1.2[Z(fct.f + Pe / Ag) + Pe] and says the ultimate strength in bending shall not be less than Muo.min.
And Muo = prestress tensile force x depth prestress + steel tensile force x tension steel depth - concrete compressive force x depth concrete - steel compressive force x compression steel depth
So keeping Z, fct.f, Ag and e (not changing tendon profile) constant, but changing number of strands per tendon, say increase;
increasing strands increases Muomin but also Muo. Obviously at different rates. My question is for the most part, is clause 8.1.6.1 an indicator of not enough strands/tendons?
3.Final question is whether you'd have any general comments about the model. Trimming wasn't a big issue due to the plate nature of the slab but I'm curious to get expert opinions on the general style of it.
thanks a lot in advance