footings sliding on rock
footings sliding on rock
(OP)
I only designed foundations for soil and never on rock (and don't intend to as there is no rock in my vicinity) but for foundations on rock... won't the foundation just slide on the rock during seismic activity since there is no friction between them?






RE: footings sliding on rock
Mike McCann
MMC Engineering
RE: footings sliding on rock
Do you also do it to soil? How stiff should the soil be before you consider doweling them?
RE: footings sliding on rock
RE: footings sliding on rock
For a mat foundation, do you put dowels on the rock underneath too?
For a spread footing.. We don't usually put dowels on the soils below.. just gravels before pouring the foundation concrete. Do you put dowels on all soils for all sizes of footings?
what formula do you use for the coefficient of friction?
RE: footings sliding on rock
For a mat foundation, which is usually defined as a large footing under a whole building or major portion thereof, I haven't heard of dowels being provided. Perhaps keys into rock if they are required. I don't see how dowels into soil would help.
RE: footings sliding on rock
mat foundations don't have dowels because they are resistant to sliding or because the dowels can't stop the sliding?
RE: footings sliding on rock
RE: footings sliding on rock
You could always saw cut, drill, chip,.... etc. slots or key ways into the rock, in various directions. Then you have a shear key in conc. problem/detail, and a much more effective means of transmitting lateral loads, than a few grouted dowels. Although, the grouted dowels might be needed for other reasons, in some instances.
RE: footings sliding on rock