Influence of footing
Influence of footing
(OP)
There is a box culvert over which I am designing a one-way slab to take pedestrian loading (85 psf). I am also designing strip footings to support the slab. However, I'd like to take the footings to the bottom of the box culvert so that the footings do not impart any loads to the box culvert. Am I doing this right?






RE: Influence of footing
If the footings are shallower such that they influence the culvert walls, it may still work, you just need to check the additional load on the walls.
RE: Influence of footing
RE: Influence of footing
RE: Influence of footing
RE: Influence of footing
If it is not too deep then take a 45 degree line of influence either side and design the footing to span between these lines of influence. Check the bearing at each end.
Other option is to put a pile/pier/caisson either side of the box culvert and design the footing to span between these and cantilever out to the line of influence.
As jike has mentioned, there may be other criteria (such as clearances) that are required by the local authority and these should be available in a design guide.
You may also need to design the floor to span over as well.
RE: Influence of footing
If you are just talking about a slab, the box must have been designed for some fill and live loads above it, so perhaps slab on grade is not unreasonable, but a bit of inquiring into what the box design was based on might be helpful.