Enlarging Existing Footing??
Enlarging Existing Footing??
(OP)
Has anyone enlarged an existing concrete spread footing by doweling reinforcing into the sides and pouring a larger footing around the 4 edges of the existing? (adding floors to existing building)
Not my idea, I would like to remove the existing and build a new footing. The builder suggested this to save shoring costs and minimize disruption to on-going operation at the footing level.
The Owner of course thought this was a wonderful idea!
I'm cross posting to geotech also.
Not my idea, I would like to remove the existing and build a new footing. The builder suggested this to save shoring costs and minimize disruption to on-going operation at the footing level.
The Owner of course thought this was a wonderful idea!
I'm cross posting to geotech also.






RE: Enlarging Existing Footing??
Building footings are small and usually redundant compared with major bridge footings which I have encased in new footings for seismic retrofit.
removing Bridge footings would significantly impact traffic, there are fewer of them (less redundant) and they are usually fairly large. This typically makes them good candidates for full enclosure or encapsulation.
Regards,

Qshake
Eng-Tips Forums:Real Solutions for Real Problems Really Quick.
RE: Enlarging Existing Footing??
1. proper bonding of old and new concrete surface.
2. Recalculating the pad thickness and rebars for shear and increased moments
3. Proper lap distances for dowels.
RE: Enlarging Existing Footing??
If you use a bonding agent, make sure that it is not a "reimulsifible".
RE: Enlarging Existing Footing??
RE: Enlarging Existing Footing??
DaveAtkins
RE: Enlarging Existing Footing??
I certainly agree with doweling the existing footing to the new concrete on 4 sides even though I did not mention it. Thanks!
RE: Enlarging Existing Footing??
RE: Enlarging Existing Footing??
On the other part, I would assume that the existing building is say two or three stories high and that you want to add say a couple more. An important consideration besides the footing capacity issue is to make the additional stories lighter.
From a different point of view and if you like the idea, what we have done in the past is to excavate immediately below the existing footings and pouring new footings right there and size them according to your analysis and design. We have framed with steel the new floor additions and has worked very well.
Regards