Pier type footing stability

[Ogrork1]

I'm designing a carport type of structure in California using 4 10 foot deep piers supporting columns that support a roof. In the IBC section 1808.2.5, piers are required to have lateral stability by connecting at least 3 piers. Wouldn't the soil surrounding the piers provide lateral stability for them? Am I misunderstanding something from this code?

 

[VAD]

I am not very familiar with your code, but would this connection have something to do with lateral stability of your overall structure in the light of seismic design considerations.

 

[Ogrork1]

I don't think that's the case VAD. It almost seems like they're treating the pier as a pile, which probably should have some form of lateral stability.

 

[LeoSC]

I believe VAD is correct. In the case of an earthquake the soil around the structure may not provide sufficient support to the pier, as it could move independently of the piers. Consequently, the pier would not have lateral support. Therefore, it is necessary to tie them together to ensure lateral stability.

Leo Sanchez

http://www.sanchezengineering.ca

 

[msquared48]

Not only that, but liquefaction or sand boils could significantly reduce or eliminate the lateral resistance seen by the pile, plus lower the point of curvature of the pile, creating instability.

The addition of grade beams between the pile would add mass and stiffness at the ground level to alter the response of the total system during such an event.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask