What is the relationship between Z and PGA?

[tmgczb]

As the title, are both the values measured at site?
Is the following data possible or not, Z=0.075 but PGA=0.4g.

 

[human909]

As I understand it UBC97 is an older and simpler US seismic design approach. Zone 1 would make sense if the site is actually 0.04g and that is a mistake. If the site's PGA is actually 0.4g then it is absolutely not Zone 1 and is a VERY seismic prone area.

EDIT: Given it says middle eastern part of Iraq this seems to be an extremely seismically active so the Zone 1 classification seems incorrect.

It uses the following zones:
Zone Z Peak Ground Acceleration
0 0 0
1 0.075 0.075g
2A 0.15 0.15g
2B 0.2 0.2g
3 0.3 0.3g
4 0.4 0.4g

 

[tmgczb]

UBC97 is an older and simpler US seismic design approach

In this way, Z in UBC is of the same value with PGA, or PGA is Z times of gravity acceleration g.

 

[TLHS]

FYI, it looks like there's 2017 Iraqi Seismic Code that uses the later ASCE methodology with Ss and S1 rather than zones, and there was potentially a further seismic map update in 2019.

 

[tmgczb]

FYI, it looks like there's 2017 Iraqi Seismic Code that uses the later ASCE methodology with Ss and S1 rather than zones, and there was potentially a further seismic map update in 2019.

We use this map in other projects.