Is External stress additive over time

[alex trent]

A bit of this is theory, butlso has some practical value.

Say I  have a house and once a week I get a 80 mph wind for 2 hours from the same direction each time.

House stands up to it fine for 10 times.

Assume no physical changes to house or foundation or surrounding soil.

Does this mean that in the next 20 or 100 times what stands up in those first winds, will stand up to the rest of the storms, or in some way is the effect additive, so at some point, the 57th 80 mph wind is not withstood as the first ones were.

[bayview]

Assuming there was no physical damage.

It would continue to withstand future winds.

But, I would assume strong winds would loosen nails, etc over time.   Possibly causing a failure.

/.

[UK4X4]

How to remove a pole out of the ground - wiggle it backwards and forwards multiple times !

How to remove a nail from two bits of wood - stress the joint repeatedly- !


The problem with stress movement is that it would start very small, not noticable to the human eye

if the stress is within the design rating the movement within the joint should be non additive

once you get out of that range then the issue becomes additive.

If I was worried about a structure I would take some very accurate measurements on diagonals and note them down

Then 6 monthly or yearly depending on visual inspections measure again

On concrete structures with cracks - you'll often seen glass plates expoxied across cracks- in other locations mirrors or measurement points epoxied in place.

Even as far as installing fiber optic brag gratings - which measure minute changes in distance

Soil distribution and support arround posts will change after each rain unless deep enough and compacted- or thoroughy drained away from the post.

Every thing on the planet moves- to some extent- most buildings stay in one piece and move together- some however fail catastrophically.

I have worries about my house moving- my foundation in theory should stay in one piece

so If it moves -the issue is what do I measure it against ? ie I need a reference point

With a post and beam construction things will probably move diferently - diagonals will be your friend

Making it as accurate and repeatable as possible will give you the best results- if you see movement - even small you can then look at remdial work before the effects are too bad

ie once you get to here- your done !

[MountainDon]

Repetitive tresses themselves are not generally the problem. Problems develop when stress exceeds the design. That can be said for anything; house, car, aircraft, blender, etc.  External, unforeseen factors can contribute to the failure of a design; the ground that UK4X4 owns for example.

So in short, IMO, if the design was proper for the expected conditions, and if the quality of construction matched the design, then the frequency should not matter. At the same time it is probably not wise to do everything to the minimum requirements.

[MountainDon]

Looks like his repair is to do much the same as the original, only in concrete this time/ Not sure it will be any better.