Another Site Seismic Site Classification Question...

[garrettk]

The IBC requires classification of the upper 100 feet of the soil profile for seismic site classification.

This makes perfect sense for traditional, shallow foundations. However, if your project requires the use of deep foundations (piles) shouldn't the soil profile which is classified begin from the tip of the piles and extend 100 feet? The structure at the ground surface will no longer feel the effects of amplification if the upper 40 feet of soils are soft or loose, but will feel the effects of the denser material the piles are founded on or in.

Is there a reason the code is not specific regarding this scenerio?

 

[eric1037]

In seismic events, there are significant lateral forces, which do affect deep foundations, and therefore, the structure.

 

[peek]

Hello Fellow Engineers:

I would greatly appreciate if anyone can shed some light on the following.

1. Is 40-ft timber pile extraction possible? Any reference such as projects (particularly in NYC area)where such piles were successfully extracted and the methods used, will be useful.

2. Unit price for cast-in-place steel pipe piles (12 in, 14in, 16in, and 18 in) in NYC area.

Thanks in advance.