Tying Pile Caps in Seismic regions.
Tying Pile Caps in Seismic regions.
(OP)
Hi,
Recieved some conflicting advice lately regarding whether or not is necessary to tie pile caps together when constructing in a siesmic area such as Middle East.. The Pile caps in question are not supporting the lateral framing structure, however they are supporting the gravity loaded columns that support a diaphragm between shear cores - Any comments greatly appreciated.
Cheers
Recieved some conflicting advice lately regarding whether or not is necessary to tie pile caps together when constructing in a siesmic area such as Middle East.. The Pile caps in question are not supporting the lateral framing structure, however they are supporting the gravity loaded columns that support a diaphragm between shear cores - Any comments greatly appreciated.
Cheers






RE: Tying Pile Caps in Seismic regions.
IBC Section 1808.2.23.1 states that if you are in SDC "C" or higher, then you need to interconnect the piles by using ties (or) slab on grade (or) grade beams. However, it seems like there may be an exception for "interior posts which are not subject to lateral load".
Can this be interpreted as follows? (maybe others can chime in)
Any building that has been detailed such that the column is not part of a lateral frame can be detailed such that you don't have to connect the pile caps?
RE: Tying Pile Caps in Seismic regions.
RE: Tying Pile Caps in Seismic regions.
Therefore, the energy gets applied to the foundation, not necessarily at grade, but some distance below.
Now a typical piled foundation has all different pile layouts for each pile cap and may include battered piles for lateral resisting walls from the building. The mode shape for each of these pile groups may be considerably different. The deflection att the top of the caps may be in different directions during a seismic event. This would increase the delta at the basse of a column versus the building overhead and add significantly to the P-delta effect on a column just needed for axial load.
To prevent this, the code requires us to tie the foundations together so that all the foundation elements move as one.
RE: Tying Pile Caps in Seismic regions.