Does accidental limit state (ALS) concern itself with variable loads? 1

[bojoka4052]

Or is it only permanent loads I should consider? I have water pressure that can be acting on my wall, or be zero, and I was wondering if I needed to consider the water pressure when looking at the accidental limit state as it varies whether its there or not.

 

[IDS]

Assuming you have checked whichever code you are working to (including any commentary and other supporting information) and that doesn't give clear guidance, I'd say use whichever loading is the worst case.

Doug Jenkins
Interactive Design Services

http://newtonexcelbach.wordpress.com/

 

[human909]

At a certain point you need to start looking at the likelihood yourself. If your wall regularly sees high water pressure then yes you should combine that with an accident limit state. If it only sees maximum water pressure during a 1 in 100 event then you might reconsider that load combination

It is little different with more regularly used combinations. The likelihood of a 1/500 year wind event and a 1/500 year seismic event occurring at the same time becomes astronomically small. So we don't normally have load combinations that assess that. Likewise maximum factored live load and a seismic event is also extremely small for most structures.

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[HTURKAK]

Dear BOJOKA 4052, i looked to your internet country domain ( NO) .. If so, EC's are valid..

- Actions due water may be considered as permanent or variable action depending on the variation with time .
- Accidental design situation covers fire,explosion, impact ,local failure..

You may provide more info. to get better responds..

 

[ThomasH]

Hi

If you are in Norway you need to look in the Norwegian code (Eurocode). Perhaps you need to consider both situations, with and without water pressure.

Thomas

 

[bojoka4052]

- Accidental design situation covers fire,explosion, impact ,local failure..

I have considered situation without water pressure, but the water pressure will be there often enough that its worth thinking about. But if accidental situation covers "fire, explosion, impact and local failure" I dont see how water pressure comes into play here, whether its permanent or variable. Going by what you quoted I feel its more correct to not take into consideration water pressure? However, I feel water pressure is something that can happen alongside accidental load case, so probably a good idea to include it.

 

[HTURKAK]

- If water and earth pressure for retaining wall , permanent action
- If water pressure load varies with time , variable action.

The combinations shall be with and without water pressure to get the max. effects.

If this is a real question, pls post the details of the structure and water pressure conditions to get better respond.