New New Zealand timber std.... NZS/AS1720.1
New New Zealand timber std.... NZS/AS1720.1
(OP)
So it was released a few days ago with no fanfare, after a 29 year wait...
Some things from the draft retained which I thought would be gone or clarified further.
Axial load capacity got crapped on, it's like no one calculated anything to compare. Or if it was the intent no one bothered mentioning something so major... Since the rho_b and rho_c factors include the ratio of E/f and are tuned to aussie timbers, I was hoping they would realise NZ timbers have quite a different ratio which results in significantly lower axial capacity for NZ timber.
They managed to retain that deflection scaling factor (k_dt), but make it so vague that no one knows what to do anymore, referencing special studies just to design a plywood shear wall....
I was really hoping it would just go away as I think it is all bollocks, OK include it if you let us work out the seismic forces based on the actual damping but not 5%. It refers you to the wood seismic design guide, and this just refers back to the draft for the large scaling factor everyone was moaning about.
In the seminars they had a few weeks ago before it was released they mention this was probably gone. But here it is as vague as ever. Basically makes designing any wood system impossible unless you're designing for really low ductilities.and then you're designing for massive forces that timber just cannot handle...
Anyone else got some thoughts?
https://engineervsheep.com
Some things from the draft retained which I thought would be gone or clarified further.
Axial load capacity got crapped on, it's like no one calculated anything to compare. Or if it was the intent no one bothered mentioning something so major... Since the rho_b and rho_c factors include the ratio of E/f and are tuned to aussie timbers, I was hoping they would realise NZ timbers have quite a different ratio which results in significantly lower axial capacity for NZ timber.
They managed to retain that deflection scaling factor (k_dt), but make it so vague that no one knows what to do anymore, referencing special studies just to design a plywood shear wall....
I was really hoping it would just go away as I think it is all bollocks, OK include it if you let us work out the seismic forces based on the actual damping but not 5%. It refers you to the wood seismic design guide, and this just refers back to the draft for the large scaling factor everyone was moaning about.
In the seminars they had a few weeks ago before it was released they mention this was probably gone. But here it is as vague as ever. Basically makes designing any wood system impossible unless you're designing for really low ductilities.and then you're designing for massive forces that timber just cannot handle...
Anyone else got some thoughts?
https://engineervsheep.com
Talk To Other Members
RE: New New Zealand timber std.... NZS/AS1720.1
RE: New New Zealand timber std.... NZS/AS1720.1
For example we've been mindful of these massive axial capacity changes and the lower bearing capacities perp to grain in our designs for a while now. The bearing using the draft 4.5MPa almost governed everything, they backed off on this value a little in the final code, but still something that will govern a lot of the time, compared with prior 8.9MPa which never really governed.
Once you consider that NZS3604 isn't being immediately updated, the divide between SED and non SED design gets very wide, and a simple stud wall design starts looking very stupid sitting next to the NZS3604 equivalent.
https://engineervsheep.com
RE: New New Zealand timber std.... NZS/AS1720.1
Add it to the list of errors I guess....
https://engineervsheep.com