Rigid Frame Foundations
Rigid Frame Foundations
(OP)
In the design of the drilled shaft to acommodate a long span rigid frame, how is the lateral force handled from the rigid frame reactions, which is substantial? Do you tie back into the slab or tie the columns together with enough tension reinforcing that the load cancels out?






RE: Rigid Frame Foundations
DaveAtkins
RE: Rigid Frame Foundations
Good luck
RE: Rigid Frame Foundations
RE: Rigid Frame Foundations
1. The hair pin solution relies on the floor slab being in place. In many cases, the metal building is erected, the roof on and in some cases the walls installed PRIOR to pouring the floors. Hence, the hair pins are not restraining the horizontal thrusts from the wind loads etc. until the floor is poured and up to strength. How do you justify this?
2. Besides using the hair pin at each column or a tie rod between columns, the footing/pier can be designed for combined loading to carry both vertical and horizontal loads. Yes, it becomes a much larger chuck of concrete, but do any of you use this option?
Just some addtional questions on what others are doing.
RE: Rigid Frame Foundations
RE: Rigid Frame Foundations
One key thing, if you use ties through the slab, make it clear on the drawings that this is a critical part of the structure design, and that removal of the slab, or cutting (say a trench) across a column line requires consultation with the engineer prior to construction. This at least would protect you from the future owner who say decides to remove the entire slab for some reason, and maybe even replaces it with asphalt paving. If this happens and there are problems with the structure down the road (perhaps not a collapse because passive pressure against the grade-beams/foundation walls may provide some level of lateral resistance), but certainly serviceability problems (a binding bridge crane for example), then you as the designer-of-record should be off the hook for problems caused by this owner, because you made your design concept clear on the drawings.