Fatigue in reinforced concrete

[ThomasH]

Hi

I have a question regarding reinforced concrete and fatigue.

I am working on a structure where fatigue loading has proven to be an issue. The code I use is Eurocode but I am currently interested in a more general approach.

The original idea was to strengthen the structure for ultimate limit loads, but when fatigue proved to be an issue, the problems grew.

Does anybody anybody have any ideas how to "remove" the existing fatigue damage? Is there any option besides removing the existing concrete and cast a new structure? And that would probably be impossible for practical reasons.

Thank you

Thomas

 

[WARose]

Does anybody anybody have any ideas how to "remove" the existing fatigue damage? Is there any option besides removing the existing concrete and cast a new structure? And that would probably be impossible for practical reasons.

Reinforcing existing members and/or fiber wrapping may be options. But one thing you may want to ask yourself is: how far down the fatigue path are you? Just because a structure has seen some fatigue.....that doesn't mean it's ultimate strength has gone to zero.

And by the way, are there more (high) cycles in this thing's future?

 

[ThomasH]

WARose, Thank you for your reply.

The problem is that the fatigue strength is more or less already spent. At least that is what the calculations show. The load causing the fatigue is wind, so there is an uncertainty in the load history.

But there are more cycles in the future then has passed. At least that is the request. But to be clear, the client is listening. This issue was an unwanted surprise that has to be considered.

Thomas

 

[WARose]

Wind loading has burned up this thing's fatigue life? That's pretty unusual. (Especially in a reinforced concrete structure.) If I were in your shoes, I would question the design to start with. (Maybe your modifications will fix that.)

 

[ThomasH]

The structure is relatively slender so the number of cycles becomes high. But my suspicion is that fatigue was not originally considered in the design. One problem is that I don't see any reasonable fix for that if it is true.

Thomas