Hi all,
I see that reductions are set for masses in Section 12.7.2, ASCE 7-16 (Effective seismic weight), that's fine, it's related to the likelyhood to have those loads during earthquakes.
It's the combinations in Sections 2.3.6 that are not fully clear to me. If I am requested to consider, for example, a vertical dead load design value equal to 1.2*dead_load (combination 6) I would say I have to consider the 1.2 amplification also in the dead seismic weight (mass from dead loads) because if I have that dead load, well the earthquake will shake all of it. I see there is no custom to do that around me, nor I find in the code any further explanation.
So, in lack of an explicit statement, I would go with a more physically meaningful interpretation (hence if dead vertical times 1.2, then also dead mass times 1.2 to be used in the seismic analysis).
If, otherwise, it is stated somewhere not to apply the 1.2 amplification to the seismic weight, ok, it's all just a design convention in the end, that's also fine. But it should be stated.
Have a good one.
I see that reductions are set for masses in Section 12.7.2, ASCE 7-16 (Effective seismic weight), that's fine, it's related to the likelyhood to have those loads during earthquakes.
It's the combinations in Sections 2.3.6 that are not fully clear to me. If I am requested to consider, for example, a vertical dead load design value equal to 1.2*dead_load (combination 6) I would say I have to consider the 1.2 amplification also in the dead seismic weight (mass from dead loads) because if I have that dead load, well the earthquake will shake all of it. I see there is no custom to do that around me, nor I find in the code any further explanation.
So, in lack of an explicit statement, I would go with a more physically meaningful interpretation (hence if dead vertical times 1.2, then also dead mass times 1.2 to be used in the seismic analysis).
If, otherwise, it is stated somewhere not to apply the 1.2 amplification to the seismic weight, ok, it's all just a design convention in the end, that's also fine. But it should be stated.
Have a good one.
