Reinforced Concrete - Finite Element Method

[MegaStructures]

I am recently interested in FEM for reinforced concrete structures. I’ve done some concrete design using code based software such as RISA, which uses plate elements with linear material models. I looked around a bit for some research that shows the difference in accuracy between these linear models and what I assume would be a more accurate non-linear model, but surprisingly I didn’t find much. There’s certainly research out there, but not quite as much as expected, or as definitive.

As a “fun” topic I wanted to know what others practical thoughts are on the differences in the analysis types. What would be the major advantage of using a non-linear material model instead of a linear one? What type of analysis would absolutely require a non-linear material model be used? In a more extreme scenario when would it ever be necessary to to take on the extremely academic approach of modeling non-linear concrete material AND physical reinforcing bar. I could imagine that a dynamic analysis might require a non-linear analysis such as a progressive collapse, or blast model, but is it ever necessary for a static load, or a quasi-static load where forcing frequency is not static, but far away from the structures natural frequency, suppose a wind load, or any live load could fall under this category.

I would be interested in research showing quantitive differences for the two methods compared to actual test results.

 

[rowingengineer]

Megastructures,
That is a very subjective question, concrete has all these fun properties like creep, shrinkage that will greatly impact you design far more that the difference in you models, as such getting these correct from testing and history is far harder to control in a model. The properties vary greatly from region to region as well so understanding whom as good wether vs poor AGG makes for differences in design thickness.

http://www.nceng.com.au/

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