Mixed Systems
Mixed Systems
(OP)
What experience does anyone have on mixing foundations around the perimeter of a building where the facade is supported on shallow foundations independent of deep foundations supporting the columns/structure? There would be movement joints between the footings and drilled shafts allowing for differential settlement (a few inches of compressible material as the footings pass over the shafts).
Similar to thread256-152238: Mixed Deep and Shallow Foundations for same building but my question involves the perimeter with precast facade and in the 4 to 6 story range.
Similar to thread256-152238: Mixed Deep and Shallow Foundations for same building but my question involves the perimeter with precast facade and in the 4 to 6 story range.





RE: Mixed Systems
RE: Mixed Systems
RE: Mixed Systems
For a precast facade, I would always support it on the structure, and at each floor.
RE: Mixed Systems
RE: Mixed Systems
Don't do it, unless you want to give Ron some forensic work in a few years. I have seen problems on single story houses that mix the two systems together.
I don't have much PCC panel experience, but does this not need to be supported by brackets at each story like Hokie said? Trying to imagine how an independent gravity system would even be possible.
RE: Mixed Systems
Fundamentally, I don't see why it can't work if the weatherproofing details account for the facade movement through the entire blg height, which is expected to be about 3/4" without remediation. I am most concerned with the differential where there is a switch from deep to shallow bearing due to long spandrels (they are hanging the panels from the columns at a couple of areas due to long spans). Again the columns go to the deep bearing.
The panel connections are all vertically slotted. But the panel horizontal joints won't line up where it switches from deep to shallow bearing. The geotech has suggested preloading to take out most all of the shallow settlement.
RE: Mixed Systems
RE: Mixed Systems