Laterally tied pilecaps

[kayah]

Consider a large building separated into different components with expansion joints. The structure is supported on short piles, tied together laterally (situated in a seismic zone).
Should the pilecaps be tied together across (below) the expansion joints, or not?
Thanks for your thoughts...

 

[whymrg]

You do not need to separate pile caps or foundations, because during earthquake, ground will move together (unless you have specific soil and geotech tells you about it).
The same applies for temperature expansion joints, if your foundations are below frost line.

 

[Focht3]

Check with your geotech. Also be aware that the lateral motion occurs in waves - literally. Each element can move at a different rate - and be out of phase with each other. You will probably need to tie them together so they don't strike one another and cause damage.