Lateral Support for Piles (UBC 97)

[MJPeterson]

I am presently working on the foundation design for a piperack. The project is located in a Zone 1 seismic area (UBC 97). UBC Sec 1807.2 states that "Individual piles caps and caissons of every structure subjected to seismic forces shall be interconnecetd by ties." The pipe rack is a standard 2 layer pipe racks 25' wide by 40' tall by 200' long. The columns are spaced at about 25 feet on center. The code seems to imply that I will need to run a grade beam (tie) between each and every pile cap of the pipe rack. Is this the correct way to interpret the code? Is there a more cost effective way to meet the code requirements? Analysis alone does not require these ties.

 

[Kramer]

The exception to UBC 1807.2 allows for "other approved methods" if "equivalent restraint can be provided." If the soils near the surface are stiff/strong enough to provide lateral restraint (based on lateral passive resistance) for the top of the pier, this is often used as an "other approved method".