Can my dining table hold four times its weight before tipping?

[Jonbarnes]

Hi - I'm designing a dining table, and am trying to calculate how much weight could be applied at the edge of the table (if someone were to lean or sit on it) before it would tip. If the legs are set in about one quarter of the total width of the top, can the outer edge of the table carry a weight (including the overhang) of four times the static weight of rest of the table (on the other side of the leg) before it will tip? It seems that people sit on tables round here more often than we eat at them, so I'm keen to figure this out before I go much further with the construction. Any help is greatly appreciated.

 

[edgepflow]

Determine the pivot point of the table (where the legs are). Then balance the moments of people and the table. For practical purposes, the weight of the table could be assumed to be concentrated at its center.

 

[Jonbarnes]

Thanks for the reply - given that the pivot point (leg location) is mid-way between the edge of the table and the center of the table, does this mean that a weight the same as the table itself would be sufficient to tip the table, if applied at the outside edge (unlikely in reality, I know)...what about the rest of the table that cantilevers beyond the center on the other side - is this not relevant?

 

[edgepflow]

Thanks for the reply - given that the pivot point (leg location) is mid-way between the edge of the table and the center of the table, does this mean that a weight the same as the table itself would be sufficient to tip the table, if applied at the outside edge (unlikely in reality, I know)...what about the rest of the table that cantilevers beyond the center on the other side - is this not relevant?

Yes, if the legs are half way between the center and edge. You have a few choices to improve this:

(a) Make the table the same weight as your guest sitting on it.
(b) Move the legs closer to the edge.
(c) Assume people put their rear end half way between the edge and leg.

 

[Jonbarnes]

Excellent, and thanks again. If my calculations are correct, it'd take a pretty burly guy right at the edge to make it tip. A couple of more normal physiques could perch a little further in without incident, and I can also fill the rather large leg members with sand to increase the mass of the table. Other than this, I can try to prevent excessive perching. A splayed foot would help, but I'd rather not...