There are structural limits and there are structural limits. In aircraft, operating limits for G-loading are set to be low enough so that the structure will remain safe to use for its entire designed service life. Exceeding these limits will result to metal fatigue and will shorten the lifetime of the aircraft. And typically makes the mechanics very unhappy, since they now have to do an extended inspection.
Then there is the ultimate structural limit, which is typically rated to be 150% of the normal operating limit. Exceeding that will result a failure of one or more of the components (crack on a wing spar or an engine mount, fuselage bending), but still it doesn't necessarily have to be catastrophic damage.
Of course both limits are calculated for an ideal, unstressed structure. Material defects and actual operation will define the actual limits. You can overstress an aircraft up to and even beyond the ultimate limit and still be fine, but you won't do it ever again with the same plane.
This. 100% this.
Unless, you know, the mechanic is Scottish.
