BCA vs AS1170.0 Table F2 Exceedence Intervals

[asixth]

Hi guys,

I have been using the latest Earthquake loading code AS1170.4-2007 that requires a kp value based on the annual probability of exceedence that is referenced from either the BCA or AS1170.0 Table F, found in Admt 2-2003 and later revised in Admt 4-2005.

Now, the BCA has two values, for Importance Category (IC) 1,2 and 3 buildings an exceedence interval of 500 years is used and for IC4 buildings an exceedence interval of 800 years.

Conversly AS1170.0 further sub-divides the IC with design lifes and the exceedence intervals vary from 25 years for an IC1 building with a design life of 6 months, to 2500 years for a IC4 building with a design life of 50 years.

How have others been deriving there kp values when using AS1170.4-2007, are you using the exceedence intervals set-out in the BCA or AS1170.0 and why is there such a variation between the two documents.

 

[sdz]

Now you have a reply
But sorry I can't help you

 

[asixth]

I guess we just don't give much coonsideration to seismic loading in Australia. Not just because of the lack of response to this thread but I can't seem to get an answer from anybody in my network either. I would like to hear how others out there are designing for Earthquake, are you:

1. Performing a simplified analysis where a lateral static force is applied at each mass/diaphragm/slab? If so, what proportion of total weight are you applying laterally?

2. Performing a dynamic analysis?

3. Using the non-codified displacement based approach?

 

[asixth]

Disregard,

The 2008 BCA has annual exceedence intervals that correlate with AS1170.0 Appendix F for a design life of 25-50 years. The BCA must have been revised in conjuction with the new Earthquake Code because the values do significantly differ from the values set out in the 2007 BCA.