Foundation Ties for Shallow Foundation per ASCE 7-16

[LockeBT]

Section 12.13.9.2.1.1 of ASCE 7-16 requires individual footings to be interconnected by ties.

Are there any exceptions for residential construction of 1-story or 2-story dwelling?

Also it seems the new ASCE7 wants you to have geotechnical investigation for literally everything. Unless I missed it where does it say you can use presumptive soil values (bearing strength and sliding resistance) from the IBC?

 

[SJBombero]

12.13.9 Specifies the requirements for liquefiable soils. If that is what you are working with then I would expect you to already have a soils report.

Technically, you need a soils report to build a doghouse, but in practice the AHJ in CA at least are not requiring them for minor residential additions. As long as the new foundation matches the existing, and the existing is not suffering from soil failure you are pretty safe. The trick however is that unless you have the original design documents, you are stuck with the presumed soil values.

 

[dauwerda]

Remember, it is typically the IBC that gets adopted (often with some amendments) by local jurisdictions as the building code. The IBC often references other codes and standards (such as ASCE 7), but it will sometimes make some changes and amendments to these references (some more stringent and some more lax). In this case, if your building code is the IBC and it allows you to use presumptive soil values, you can - it supersedes anything that might be different in ASCE 7.

Also, residential construction is usually designed per the IRC (which is very prescriptive), the IBC would only come into play for situations that aren't covered by the IRC.